Withania somnifera root extract inhibits MGO-induced skin fibroblast cells dysfunction via ECM-integrin interaction

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal, known as Ashwagandha, has long been used in traditional medicine in Ayurveda, India, a representative adaptogen. The main active constituents of W. somnifera are withanolides, and the root is often used as a medicine with a wide range of pharmacological activities, which can be used to treat insomnia, neurasthenia, diabetes mellitus and skin cancer.

AIM OF THE STUDY

Whole-component qualitative and quantitative analyses were performed on W. somnifera. We explored the ameliorative effect of the adaptogen representative plant W. somnifera on the senescence events of MGO-injured fibroblasts and its action mechanism and verified the hypotheses that WS can inhibit the accumulation of AGEs and regulate the dynamic balance among the components of the ECM by modulating the expression of integrin β1 receptor; as a result, WS maintains cellular behavioural and biological functions in a normal range and retards the aging of skin from the cellular level.

MATERIALS AND METHODS

In this study, the components of WS were first qualitatively and quantitatively analysed by HPLC fingerprinting and LC-MS detection. Second, a model of MGO-induced injury of CML-overexpressing fibroblasts was established. ELISA was used to detect CML expression and the synthesis of key extracellular matrix ECM protein components COL1, FN1, LM5 and TNC synthesis; CCK-8 was used to detect cell viability; EDU was used to detect cell proliferation capacity; fluorescence was used to detect cell adhesion capacity; and migration assay were used to detect cell migration capacity; qRT-PCR was used to detect the regulatory pathway TGF-β1 and MMP-2, MMP-9 in ECMs; immunofluorescence was used to detect the expression of ITGB1; and WB was used to detect the expression of COL1, FN1, LM5, Tnc, TGF-β1, MMP-2, MMP-9 and ITGB1.

RESULTS

In total, 27 active ingredients were analysed from WS, which mainly consisted of withanolide components, such as withaferin A and withanolide A. Based on the model of MGO-induced fibroblast senescence injury, WS significantly inhibited CML synthesis. By up-regulating the expression of integrin β1, it upregulated the expression of the TGF-β1 gene, which is closely related to the generation of ECMs, downregulated the expression of the MMP-2 and MMP-9 genes, which are closely related to the degradation of ECMs, maintained the dynamic balance of the four types of ECMs, and improved cell viability as well as proliferation, migration and adhesion abilities.

CONCLUSIONS

WS can prevent cellular behavioural dysfunction and delay skin ageing by reducing the accumulation of CML, upregulating the expression of the ITGB1 receptor, maintaining the normal function of ECM-integrin receptor interaction and preventing an imbalance between the production and degradation of protein components of ECMs. The findings reported in this study suggest that WS as a CML inhibitor can modulate ECM-integrin homeostasis and has great potential in the field of aging retardation.

Enhanced production of withaferin A from the hairy root culture of Withania somnifera via synergistic effect of Methyl jasmonate and β-cyclodextrin

Due to low amounts of withanolides produced in some plants and high demand for various applications, their biotechnological production is widely researched. The effects of two explant types (i.e., leaf and stem from the in vitro seedlings of three genotypes of Withania somnifera) and four Rhizobium strains (i.e., LBA 9402, A4, ATCC 15834, and C58C1) to improve hairy root formation efficiency was studied. Furthermore, the combined effects of β-cyclodextrin (β-CD) and methyl jasmonate (MeJA) on withaferin A production after 48 h exposure time was examined. Four hairy roots having the maximum percentage of induced roots and mean number of induced roots to analyze their growth kinetics and identified G3/ATCC/LEAF culture having the maximum specific growth rate (μ = 0.036 day-1) and growth index (GI = 9.18), and the shortest doubling time (Td = 18.82 day) were selected. After 48 h exposure of G3/ATCC/LEAF culture to different elicitation conditions, maximum amounts of withaferin A were produced in samples co-treated with 0.5 mM β-CD + 100 μM MeJA (9.57 mg/g DW) and 5.0 mM β-CD + 100 μM MeJA (17.45 mg/g DW). These outcomes represented a 6.8-fold and 12.5-fold increase, respectively, compared to the control. Similarly, combined β-CD/MeJA elicitation increased gene expression levels of HMGR, SQS, SMT-1, and SDS/CYP710A involved in withanolides biosynthetic pathway, of which just SMT-1 had significant correlation with withaferin A production. These results demonstrated the superiority of G1-leaf explant and ATCC 15834 for hairy root induction, and revealed synergistic effect of MeJA and β-CD on withaferin A production.

Differential regulation of key triterpene synthase gene under abiotic stress in Withania somnifera L. Dunal and its co-relation to sterols and withanolides

Withania somnifera (Ashwagandha), is one of the most reputed Indian medicinal plants, having immense pharmacological activities due to the occurrence of withanolides. The withanolides are biosynthesized through triterpenoid biosynthetic pathway with the involvement of WsCAS leading to cyclization of 2, 3 oxidosqualene, which is a key metabolite to further diversify to a myriad of phytochemicals. In contrast to the available reports on the studies of WsCAS in withanolide biosynthesis, its involvement in phytosterol biosynthesis needs investigation. Present work deals with the understanding of role of WsCAS triterpenoid synthase gene in the regulation of biosynthesis of phytosterols & withanolides. Docking studies of WsCAS protein revealed Conserved amino acids, DCATE motif, and QW motif which are involved in efficient substrate binding, structure stabilization, and catalytic activity. Overexpression/silencing of WsCAS leading to increment/decline of phytosterols confers its stringent regulation in phytosterols biosynthesis. Differential regulation of WsCAS on the metabolic flux towards phytosterols and withanolide biosynthesis was observed under abiotic stress conditions. The preferential channelization of 2, 3 oxidosqualene towards withanolides and/or phytosterols occurred under heat/salt stress and cold/water stress, respectively. Stigmasterol and β-sitosterol showed major contribution in high/low temperature and salt stress, and campesterol in water stress management. Overexpression of WsCAS in Arabidopsis thaliana led to the increment in phytosterols in general. Thus, the WsCAS plays important regulatory role in the biosynthetic pathway of phytosterols and withanolides under abiotic stress conditions.

Dietary restriction-induced alterations on estrogen receptor alpha expression in regulating fertility in male Coturnix coturnix japonica: Relevance of Withania somnifera in modulation of inflammation and oxidative stress in testis

PROBLEM

Reproductive performance of animals gets affected by nutritional restrictions which act as potential stressors leading to hormonal imbalance and testicular inflammation, the major causes of infertility. Withania somnifera (WS), well-known traditional medicinal plant, has been used as antistress and infertility treatment. Therefore, the present study looks into the ameliorative effects of WS on the reproductive and immune system of male Coturnix coturnix japonica in stressed conditions like water and food restriction focussing on the modulation in estrogen receptor alpha (ERα).

METHOD OF STUDY

Biochemical estimations for oxidative stress, histological alterations, immuno-fluorescent localization of ERα, interleukin (IL)-1β, IL-4, and interferon gamma (IFN-γ) in testicular cells were performed.

RESULTS

Nutritional restriction declines endogenous estradiol, ERα in testicular cells while it elevates corticosterone leading to oxidative stress in testis thereby reducing fertility by decrease in sperm. Results indicate significant reversal in all the parameters after the administration of WS by improving testicular cell morphology, increased superoxide and catalase activity thus reducing oxidative stress. WS increases spermatogenesis and enhances expression of ERα in testicular cells in quail. Further, WS increases IL-4, decreases IL-1β and IFN-γ expression in testis, thereby improving immune profile contrary to stressed conditions.

CONCLUSION

WS stimulates HPG-axis even after stress resulting in increased endogenous estradiol which stimulates the expression of ERα in testis; increases sperm count and immunity thereby improving the reproductive performance. WS may be the best therapy against nutritional-restriction stress induced reproductive toxicity by reducing oxidative stress mediated inflammatory response via increased testicular expression of ERα in quail.

Withania somnifera ameliorates sexual arousal and impotence in stressed sexually sluggish male rats by modulating neurotransmitters and NO/cGMP/PDE5α pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Psychological stress is a growing global threat to male sexual potency and erection efficiency. Withania somnifera (L.) Dunal (WS), also known as Ashwagandha, is a well-known Ayurvedic herb. The roots of Withania somnifera improve the body's ability to handle stress, strengthen the immune system, promote healthy ageing, and have aphrodisiac properties with male sexual stimulation effects. Despite its widespread acceptance as an Ayurvedic stress-relieving drug with beneficial effects on male reproductive health, Withania somnifera has yet to be studied for its potential role in improving the sexual arousal and erectile dysfunction of psychologically stressed sexually sluggish males.

AIM OF THE STUDY

To investigate the therapeutic effects of purified root powder of Withania somnifera on sexual behaviour and erectile efficiency in stressed sexually sluggish male rats.

MATERIALS AND METHODS

Sexually sluggish male rats were screened by premating tests after being exposed to a psychological stressor, restraint stress, 3 h/day for 30 days. Subsequently, these rats were treated with purified root powder of WS (150 or 300 mg/kg/day-PO) or sildenafil (5 mg/kg/day-PO) for 30 days. The rats were sacrificed after 24 h of the last treatment, and the effects on various factors related to sexual behaviour, penile histomorphology, serum hormones, and neurotransmitters associated with sexual arousal and penile erection were examined.

RESULTS

WS treatment improves prosexual and sexual behaviour in psychologically stressed sexually sluggish male rats by increasing non-contact erections and mounts, intromission, and ejaculation frequencies, while decreasing sexual exhaustion by decreasing post-ejaculation intervals and latencies. WS also modulates neurotransmitters and hormones associated with sexual desire and stress, including dopamine, serotonin, corticosterone, and prolactin. Additionally, there was also a dose-dependent increase in serum LH, FSH, and testosterone levels. The administration of WS to sexually sluggish rats resulted in significant improvements in penile histomorphology, specifically by increasing the ratio of smooth muscle (SM) to collagen. Furthermore, in sexually sluggish rats, WS treatment increased the expression of markers associated with penile erection facilitation, such as nNOS, eNOS, p-Akt, nitric oxide, acetylcholine, and cGMP. Notably, WS treatment decreased the expression of penile PDE5α in these rats in a dose-dependent manner. Remarkably, the therapeutic effects of WS are comparable to those of sildenafil.

CONCLUSIONS

Purified root powder of Withania somnifera was found to improve sexual arousal and erection efficiency in stressed, sexually sluggish male rats. This improvement was achieved by modulating the HPG and HPA axes as well as the NO/cGMP/PDE5α pathway involved in penile erection. Thus, our findings strongly support the potent therapeutic potential of purified root powder of WS in improving the sexual health of stressed sexually sluggish rats.

Study of Drug Targets Associated With Oncogenesis and Cancer Cell Survival and the Therapeutic Activity of Engineered Ashwagandha Extract Having Differential Withanolide Constitutions

Ashwagandha (Withania somnifera) has gained worldwide popularity for a multitude of health benefits inclusive of cancer-preventive and curative effects. Despite numerous research data supporting the benefits of this wonder herb, the actual use of ashwagandha for cancer treatment in clinics is limited. The primary reason for this is the inconsistent therapeutic outcome due to highly variable composition and constitution of active ingredients in the plant extract impacting ashwagandha's pharmacology. We investigate here an engineered yield: an ashwagandha extract (Oncowithanib) that has a unique and fixed portion of active ingredients to achieve consistent and effective therapeutic activity. Using the MCF7 cell line, Oncowithanib was studied for its anti-neoplastic efficacy and drug targets associated with cell cycle regulation, translation machinery, and cell survival and apoptosis. Results demonstrate a dose-dependent decline in Oncowithanib-treated MCF7 cell viability and reduced colony-forming ability. Treated cells showed increased cell death as evidenced by enhancement of Caspase 3 enzyme activity and decreased expressions of cell proliferation markers such as Ki67 and Aurora Kinase A. Oncowithanib treatment was also found to be associated with expressional suppression of key cellular kinases such as RSK1, Akt1, and mTOR in MCF7 cells. Our findings indicate that Oncowithanib decreases MCF7 cell survival and propagation, and sheds light on common drug targets that might be good candidates for the development of cancer therapeutics. Further in-depth investigations are required to fully explore the potency and pharmacology of this novel extract. This study also highlights the importance of the standardization of herbal extracts to get consistent therapeutic activity for the disease indication.

Survival tactics of an endangered species Withania coagulans (Stocks) Dunal to arid environments

Withania coagulans is a valuable medicinal plant with high demand, but its wild growth and local usage pose a threat to its natural habitat. This study aims to understand the plant's growth, anatomy, and physiology in different environmental conditions to aid in conservation and re-vegetation efforts. Fifteen differently adapted populations of Withania coagulans were collected from diverse ecological regions, viz., (i) along the roadside, (ii) hilly areas, (iii) barren land, and (iv) wasteland to unravel the adaptive mechanisms that are responsible for their ecological success across heterogenic environments of Punjab, Pakistan. The roadside populations had high values of photosynthetic pigments, total soluble proteins, root endodermis thickness, stem and leaf cortical thickness, and its cell area. The populations growing in hilly areas showed better growth performance such as vigorous growth and biomass production. Additionally, there was enhanced accumulation of organic osmolytes (glycine betaine and proline), chlorophyll content (chl a/b), and enlarged epidermal cells, cortical cells, vascular bundles, metaxylem vessels, and phloem region in roots. In case of stem area, epidermal thickness, cortical thickness, vascular bundle, and pith area showed improved growth. However, the barren land population showed significant increase in carotenoid contents, vascular bundle area, and metaxylem area in roots, and xylem vessels and phloem area in stems and leaves. The wasteland population surpassed the rest of the populations in having greater root dry weight, higher shoot ionic contents, increased root area, thick cortical, and vascular bundle area in roots. Likewise, cortical thickness and its cell area, and pith area in stems, whereas large vascular bundles, phloem region, and high stomatal density were recorded in leaves. Subsequently, natural populations showed the utmost behavior related to tissue organization and physiology in response to varied environmental conditions that would increase the distribution and survival of species.

A critical assessment of the whole plant-based phytotherapeutics from Withania somnifera (L.) Dunal with respect to safety and efficacy vis-a-vis leaf or root extract-based formulation

Withania somnifera (L.) Dunal, popularly known as Ashwagandha or Indian ginseng, is well acclaimed for its health-enhancing effects, including its potent immunomodulatory, anti-inflammatory, neuroprotective, and anti-tumorigenic properties. The prime biological effectors of these attributes are a diverse group of ergostane-based steroidal lactones termed withanolides. Withanones and withanosides are distributed differentially across the plant body, whereas withanolides and withanones are known to be more abundant in leaves, while withanosides are found exclusively in the roots of the plants. Standardized W. somnifera extract is Generally Recognized as Safe (GRAS)-affirmed, however, moderate to severe toxic manifestations may occur at high dosages. Withaferin A, which also happens to be the primary bioactive ingredient for the effectiveness of this plant. There have been contrasting reports regarding the distribution of withaferin A in W. somnifera. While most reports state that the roots of the plant have the highest concentrations of this phytochemical, several others have indicated that leaves can accumulate withaferin A in proportionately higher amounts. A comprehensive survey of the available reports suggests that the biological effects of Ashwagandha are grossly synergistic in nature, with many withanolides together mediating the desired physiological effect. In addition, an assorted formulation of withanolides can also neutralize the toxic effects (if any) associated with withaferin A. This mini-review presents a fresh take on the recent developments regarding the safety and toxicity of the plant, along with a critical assessment of the use of roots against leaves as well as whole plants to develop therapeutic formulations. Going by the currently available scientific evidence, it is safe to infer that the use of whole plant formulations instead of exclusively root or leaf recipes may present the best possible option for further exploration of therapeutic benefits from this novel medicinal plant.HighlightsTherapeutic potential of withanolides owes to the presence of α,β unsaturated ketone which binds to amines, alcohols, and esters and 5β, 6β epoxy group which react with side chain thiols of proteins.At concentrations above NOAEL (no observed adverse effect level), the same mechanisms contribute towards toxicity of the molecule.Although withanosides are found exclusively in roots, whole plants have higher contents of withanones and withanolides.Whole plant-based formulations have other metabolites which can nullify the toxicity associated with roots.Extracts made from whole plants, therefore can holistically impart all therapeutic benefits as well as mitigate toxicity.

Withania somnifera inhibits photorefractoriness which triggers neuronal apoptosis in both pre-optic and paraventricular hypothalamic area of Coturnix coturnix japonica: involvement of oxidative stress induced p53 dependent Caspase-3 mediated low immunoreactivity of estrogen receptor alpha

Light has a very important function in the regulation of the normal physiology including the neuroendocrine system, biological rhythms, cognitive behavior, etc. The variation in photoperiod acts as a stressor due to imbalance in endogenous hormones. Estrogen and its receptors ER alpha and beta play a vital role in the control of stress response in birds. The study investigates the estrogenic effects of a well-known medicinal plant Withania somnifera (WS), mediated by estrogen receptor alpha (ERα) in the hypothalamic pre-optic area (POA) and paraventricular nuclei (PVN). Further the study elucidates its anti-oxidants and anti-apoptotic activities in the brain of Japanese quail. To validate this hypothesis, mature male quails were exposed to long day length for 3 months and then transferred to intermediate day length to become photorefractory (PR) while controls were still continued under long daylength. Supplementation of WS root extract in PR quail increases plasma estrogen and lowers corticosterone. Further, in PR quail the variation in light downregulates immunoreactivity of ERα, oxidative stress and antioxidant enzyme activities i.e. superoxide dismutase and catalase in the brain. Neuronal apoptosis was observed in the POA and PVN of PR quail as indicated by the abundant expression of Caspase-3 and p53 which reduces after the administration of WS root extract. The neuronal population also found to decrease in PR although it increased in WS administered quails. Further, the study concluded that change in photoperiod from 3 months exposure of 16L: 8D to 13.5L: 10.5D directly activates neuronal apoptosis via expression of Caspase3 and p53 expression in the brain and increases neuronal and gonadal oxidative stress while WS root extract reverses them via enhanced estrogen and its receptor ERα expression in the hypothalamic pre-optic and PVN area of Japanese quail.

Three-Way Cell-Based Screening of Antistress Compounds: Identification, Validation, and Relevance to Old-Age-Related Pathologies

A variety of environmental stress stimuli have been linked to poor quality of life, tissue dysfunctions, and ailments including metabolic disorders, cognitive impairment, and accelerated aging. Oxidative, metal, and hypoxia stresses are largely associated with these phenotypes. Whereas drug development and disease therapeutics have advanced remarkably in last 3 decades, there are still limited options for stress management. Because the latter can effectively decrease the disease burden, we performed cell-based screening of antistress compounds by recruiting 3 chemical models of oxidative (paraquat), metal (cadmium nitrate), or hypoxia (cobalt chloride) stresses. The screening of 70 compounds for their ability to offer protection against oxidative, metal, and hypoxia stresses resulted in the selection of 5 compounds: Withaferin-A (Wi-A), methoxy Withaferin-A (mWi-A), Withanone (Wi-N), triethylene glycol (TEG), and Ashwagandha (Withania somnifera) leaf M2-DMSO extract (M2DM). Molecular assays revealed that whereas stress caused increase in (a) apoptosis, (b) reactive oxygen species accumulation coupled with mitochondrial depolarization, (c) DNA double-strand breaks, and (d) protein aggregation, low nontoxic doses of the selected compounds caused considerable protection. Furthermore, Wi-N, TEG, and their mixture-treated normal human fibroblasts (at young, mature, and senescent stages representing progressively increasing accumulation of stress) showed increase in proliferation. Taken together, these results suggested 3-way (oxidative, metal, and hypoxia) antistress potential of Wi-N and TEG that may be useful for management of environmental and old-age-related pathologies.

Withania somnifera extracts induced attenuation of HIV-1: a mechanistic approach to restrict viral infection

BACKGROUND

Several anti-retroviral drugs are available against Human immunodeficiency virus type-1, but have multiple adverse side effects. Hence, there is an incessant compulsion for effectual anti-retroviral agents with minimal or no intricacy. Traditionally, natural products have been the most successful source for the development of new medications. Withania somnifera, also known as Ashwagandha, is the utmost treasured medicinal plant used in Ayurveda, which holds the potential to give adaptogenic, immunomodulatory, and antiviral effects. However, its effect on HIV-1 replication at the cellular level has never been explored. Herein, we focused on the anti-HIV-1 activity and the probable mechanism of action of hydroalcoholic and aqueous extracts of Withania somnifera roots and its phytomolecules.

METHODS

The cytotoxicity of the extracts was determined through MTT assay, while the in vitro anti-HIV-1 activity was assessed in TZM-bl cells against the HIV-1 strains of X4 and R5 subtypes. Results were confirmed in peripheral blood mononuclear cells, using the HIV-1 p24 antigen assay. Additionally, the mechanism of action was determined through the Time of Addition assay, which was further validated through the series of enzymatic assays, i.e. HIV-1 Integrase, Reverse transcriptase, and Protease assays. To explore the role of the identified active metabolites of Withania somnifera in antiretroviral activity, molecular docking analyses were performed against these key HIV-1 replication enzymes.

RESULTS

The hydroalcoholic and aqueous extracts of Withania somnifera roots were found to be safer at the sub-cytotoxic concentrations and exhibited their ability to inhibit replication of two primary isolates of HIV-1 through cell-associated and cell-free assays, in dose-dependent kinetics. Several active phytomolecules found in Withania somnifera successfully established hydrogens bonds in the active binding pocket site residues responsible for the catalytic activity of HIV replication and therefore, signifying their role in the attenuation of HIV-1 infection as implied through the in silico molecular docking studies.

CONCLUSIONS

Our research identified both the hydroalcoholic and aqueous extracts of Withania somnifera roots as potent inhibitors of HIV-1 infection. The in silico analyses also indicated the key components of Withania somnifera with the highest binding affinity against the HIV-1 Integrase by 12-Deoxywithastramonolide and 27-Hydroxywithanone, HIV-1 Protease by Ashwagandhanolide and Withacoagin, and HIV-1 Reverse transcriptase by Ashwagandhanolide and Withanolide B, thereby showing possible mechanisms of HIV-1 extenuation. Overall, this study classified the role of Withania somnifera extracts and their active compounds as potential agents against HIV-1 infection.

The growth performance, antioxidant and immune responses, and disease resistance of Litopenaeus vannamei fed on diets supplemented with Indian ginseng (Withania somnifera)

In the current study, white-leg shrimp (Litopenaeus vannamei) were fed on diets containing varying doses of Withania somnifera aqueous extract (WSAE) at a rate of 0 (control), 0.5, 1.0, and 2.0 g/kg feed for 56 days. After the feeding trial, shrimps in all groups were challenged with the exposure to Vibrio harveyi for ten days during which animals' mortality was observed. It is noted that the dietary WSAE linearly and quadratically stimulated shrimp's growth indices particularly at the treatment of 2.0 g/kg feed. Compared to the control group, the WSAE-fed L. vannamei had significantly higher villi length, villi width, and absorption area particularly in the treatment of 2.0 g/kg feed. Furthermore, L. vannamei fed on WSAE-enriched diets consumed more feed and exhibited higher total proteolytic activity, lipase, and α-amylase activities as compared with the control group. The dietary WSAE at escalating levels linearly and quadratically enhanced the antioxidant activity (serum superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), total antioxidant capacity, and reduced glutathione) and the immune response (total hemocyte counts, total protein, lysozyme, and phagocytic activity). Similarly, the mRNA expression levels of cMn-SOD, CAT, and GPx genes were linearly and quadratically upregulated in the hepatopancreas of L. vannamei fed on WSAE-enriched diets (especially in the 2.0 g/kg feed treatment), while their lowest levels were significantly observed in the control group. On the other hand, malondialdehyde levels were significantly decreased in WSAE-supplemented shrimp groups, and its highest levels were observed in animals fed on the control diet. After the bacterial exposure, the survival rates of L. vannamei fed on 1.0 and 2.0 g WSAE/kg feed (61.3% and 66.7%, respectively) were higher than those in the control animals. Taken together, the results obtained herein indicate that inclusion of WSAE in diets of L. vannamei effectively enhanced the growth, antioxidant biomarkers, immune response, and resistance to the V. harveyi infection, particularly at the treatment of 2.0 g/kg feed.

Withanolides from Withania somnifera Ameliorate Neutrophil Infiltration in Endotoxin-Induced Peritonitis by Regulating Oxidative Stress and Inflammatory Cytokines

Identification of novel anti-inflammatory strategies are needed to avoid the side effects associated with the currently available therapies. Use of anti-inflammatory herbal remedies is gaining attention. The purpose of the present investigation was to evaluate the pharmacological potential of the withanolide-rich root extracts of the medical plant Withania somnifera (L.) Dunal using in vivo and in vitro models of endotoxin-induced inflammation and oxidative stress. The pharmacological effects of W. somnifera root extracts were evaluated using a mouse model of endotoxin (lipopolysaccharide)-induced peritonitis and various relevant human cell lines. HPLC analysis of the W. somnifera root extracts identified the presence of various bioactive withanolides. In vivo challenge of mice with endotoxin resulted in the infiltration of various leukocytes, specifically neutrophils, along with monocytes and lymphocytes into the peritoneal cavity. Importantly, prophylactic treatment with W. somnifera inhibited the migration of neutrophils, lymphocytes, and monocytes and decreased the release of interleukin-1β, TNF-α, and interleukin-6 cytokines into the peritoneal cavity as identified by ELISA. Liver (glutathione peroxidase, glutathione, glutathione disulfide, superoxide dismutase, malondialdehyde, myeloperoxidase) and peritoneal fluid (nitrite) biochemical analysis revealed the antioxidant profile of W. somnifera. Similarly, in human HepG2 cells, W. somnifera significantly modulated the antioxidant levels. In THP-1 cells, W. somnifera decreased the secretion of interleukin-6 and TNF-α. In HEK-Blue reporter cells, W. somnifera inhibited TNF-α-induced nuclear factor-κB/activator protein 1 transcriptional activity. Our findings suggest the pharmacological effects of root extracts of W. somnifera rich in withanolides inhibit neutrophil infiltration, oxidative hepatic damage, and cytokine secretion via modulating the nuclear factor-κB/activator protein 1 pathway.

Role of Withaferin A and Its Derivatives in the Management of Alzheimer's Disease: Recent Trends and Future Perspectives

Globally, Alzheimer's disease (AD) is one of the most prevalent age-related neurodegenerative disorders associated with cognitive decline and memory deficits due to beta-amyloid deposition (Aβ) and tau protein hyperphosphorylation. To date, approximately 47 million people worldwide have AD. This figure will rise to an estimated 75.6 million by 2030 and 135.5 million by 2050. According to the literature, the efficacy of conventional medications for AD is statistically substantial, but clinical relevance is restricted to disease slowing rather than reversal. Withaferin A (WA) is a steroidal lactone glycowithanolides, a secondary metabolite with comprehensive biological effects. Biosynthetically, it is derived from Withania somnifera (Ashwagandha) and Acnistus breviflorus (Gallinero) through the mevalonate and non-mevalonate pathways. Mounting evidence shows that WA possesses inhibitory activities against developing a pathological marker of Alzheimer's diseases. Several cellular and animal models' particulates to AD have been conducted to assess the underlying protective effect of WA. In AD, the neuroprotective potential of WA is mediated by reduction of beta-amyloid plaque aggregation, tau protein accumulation, regulation of heat shock proteins, and inhibition of oxidative and inflammatory constituents. Despite the various preclinical studies on WA's therapeutic potentiality, less is known regarding its definite efficacy in humans for AD. Accordingly, the present study focuses on the biosynthesis of WA, the epidemiology and pathophysiology of AD, and finally the therapeutic potential of WA for the treatment and prevention of AD, highlighting the research and augmentation of new therapeutic approaches. Further clinical trials are necessary for evaluating the safety profile and confirming WA's neuroprotective potency against AD.

Ashwagandha: Advances in plant biotechnological approaches for propagation and production of bioactive compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera is one of the most extensively delved Ayurvedic medicine. Apart from rejuvenation and increasing longevity, it has several other properties such as immunomodulation, anti-cancer, anti-stress and neuroprotection. Because of its prevailing use and increasing demand, it becomes prudent to scientifically evaluate and document both its propagation and production of desired phytoconstituents.

AIM OF THE STUDY

This review aims to highlight the research progress achieved on various biotechnological and tissue culture aspects of Withania somnifera and to cover up-to-date information regarding in-vitro propagation and production of withanolides.

MATERIALS AND METHODS

Significant published studies were identified for the years 2000-2018 using Elsevier-Science Direct, Pubmed and Google scholar and several research studies in our laboratory. Following keywords such as "plant extracts", "in vitro cultures", "callus and suspension culture", "micropropagation", "hairy root cultures" were used. Further, "Withania somnifera", "secondary metabolites specially withanolides", "molecular techniques" and "in vitro conservation" were used to cross-reference the keywords.

RESULTS

Ashwagandha comprises a broad spectrum of phytochemicals with a wide range of pharmacological properties. W. somnifera seeds have reduced viability and germination rates; thus, its regular cultivation method fails to achieve commercial demands mainly for the production of desired phytoconstituents. Cultivation of plant cells/tissues under in vitro conditions and development of various biotechnological strategies will help to build an attractive alternative to provide adequate quality and quantity raw materials. Recently, a large number of in vitro protocols has developed for W. somnifera not only for its propagation but for the production of secondary metabolites as well. Present work highlights a variety of biotechnological strategies both for prompt propagation and production of different bioactive secondary metabolites.

CONCLUSION

The present review focuses on the development and opportunities in various biotechnological approaches to accomplish the global demand of W. somnifera and its secondary metabolites. This review underlines the advances in plant biotechnological approaches for the propagation of W. somnifera and production of its bioactive compounds.

Metabolomics of Withania somnifera (L.) Dunal: Advances and applications

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera L. (Solanaceae), commonly known as Ashwagandha or Indian ginseng, is used in Ayurveda (Indian system of traditional medicine) for vitality, cardio-protection and treating other ailments, such as neurological disorders, gout, and skin diseases.

AIM OF THE REVIEW

We present a critical overview of the information on the metabolomics of W. somnifera and highlight the significance of the technique for use in quality control of medicinal products. We have also pointed out the use of metabolomics to distinguish varieties and to identify best methods of cultivation, collection, as well as extraction.

MATERIAL AND METHODS

The relevant information on medicinal value, phytochemical studies, metabolomics of W. somnifera, and their applications were collected from a rigorous electronic search through scientific databases, including Scopus, PubMed, Web of Science and Google Scholar. Structures of selected metabolites were from the PubChem.

RESULTS

The pharmacological activities of W. somnifera were well documented. Roots are the most important parts of the plant used in Ayurvedic preparations. Stem and leaves also have a rich content of bioactive phytochemicals like steroidal lactones, alkaloids, and phenolic acids. Metabolomic studies revealed that metabolite profiles of W. somnifera depended on plant parts collected and the developmental stage of the plant, besides the season of sample collection and geographical location. The levels of withanolides were variable, depending on the morpho/chemotypes within the species of W. somnifera. Although studies on W. somnifera were initiated several years ago, the complexity of secondary metabolites was not realized due to the lack of adequate and fool-proof technology for phytochemical fingerprinting. Sophistications in chromatography coupled to mass spectrometry facilitated the discovery of several new metabolites. Mutually complementary techniques like LC-MS, GC-MS, HPTLC, and NMR were employed to obtain a comprehensive metabolomic profile. Subsequent data analyses and searches against spectral databases enabled the annotation of signals and dereplication of metabolites in several numbers without isolating them individually.

CONCLUSIONS

The present review provides a critical update of metabolomic data and the diverse application of the technique. The identification of parameters for standardization and quality control of herbal products is essential to facilitate mandatory checks for the purity of formulation. Such studies would enable us to identify the best geographical location of plants and the time of collection. We recommend the use of metabolomic analysis of herbal products based on W. somnifera for quality control as well as the discovery of novel bioactive compounds.

Impact of green synthesized WcAgNPs on in-vitro plant regeneration and withanolides production by inducing key biosynthetic genes in Withania coagulans

Withania coagulans (L.) Dunal bio-synthesized silver nanoparticles (WcAgNPs) worked as an abiotic elicitor or auto-catalyst that enhanced root regeneration and withanolides production in in-vitro regenerated W. coagulans. Rapid development in the production / consumption of silver nanoparticles (AgNPs) raised serious concern over its effects on the growth of natural plant community. The knowledge related to impact of AgNPs on plant growth and biocompatibility is increasing day by day, but comprehensive mechanism and gaps regarding their impacts on plant health have yet to be addressed. In the present study, we investigated the impact of Withania coagulans biosynthesized AgNPs (WcAgNPs) on in-vitro plant growth and withanolides production. Obtained results showed that the low concentrations of WcAgNPs significantly induced the plant growth by regulating oxidative stress via anti-oxidative defense system. Physiological, morphology and anatomical features also reflected healthy plant growth under low WcAgNPs exposure. While higher concentrations of WcAgNPs have a negative impact on W. coagulans plant growth due to induced lipid peroxidation, ROS accumulation, and root cell death. At lower concentrations, WcAgNPs have shown a positive effect on in-planta withanolides biosynthesis stimulating withanolide A and withaferin A up to 11.15-22.8-fold, respectively. Furthermore, the expression of withanolides biosynthetic genes were also quantified upon WcAgNPs exposure and terpenes biosynthetic genes showed over-expression. Thus, the present study concludes that the lower concentrations of WcAgNPs positively induced plant growth via improved root organogenesis and also have potential to act as an elicitor for withanolides production.

Evaluation of Matcha (Camellia sinensis) and Ashwagandha (Withania somnifera) Efficacy Against Utero-Ovarian Injury in Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Female infertility and reproductive problems have increased worldwide. Medical treatment of such conditions has high costs with various side effects. Alternative medicine, essentially herbal plants, has been projecting to improve female infertility and reproductive health. This study was aimed to evaluate the efficacy of single or combined administration of matcha and ashwagandha teas against H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;-induced Utero-ovarian oxidative injury and cell death in female rats. &lt;b&gt;Materials and Methods:&lt;/b&gt; Fifty adult female rats were used. Ten rats were kept healthy while in others Utero-ovarian oxidative injury was induced by drinking 1% H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; water &lt;i&gt;ad libitum&lt;/i&gt;. Injured rats were divided into 4 groups (10 rats/each), one group set as injured control and the other 3 groups the doses of supplemented teas were 200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt. and 100 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt. from each or both teas, respectively. &lt;b&gt;Results:&lt;/b&gt; The results displayed that both teas contain active components including flavonoids, polyphenols and possess antioxidant activity. Drinking 1% H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; water significantly (p&lt;u&gt;<&lt;/u&gt;0.01)decreased the estrous cycle time, body, ovary and uterus weights, serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone and estrogen (E2) levels, uterine and ovarian superoxide dismutase (SOD) activity and reduced glutathione (GSH) level while caused a substantial increase (p&lt;u&gt;<&lt;/u&gt;0.01) in uterine and ovarian malondialdehyde (MDA) level, DNA fragmentation percent, caspase-3 (Casp-3), 8-hydroxydeoxyguanosine (8-OHdG), tumour necrosis factor-α (TNF-α), prostaglandin E2 (PGE2) levels as well as cyclooxygenase-2 (COX-2) activity. Moreover, microscopic observations of uterine and ovarian tissues were consistent with the biochemical results. &lt;b&gt;Conclusion:&lt;/b&gt; Oral administration of tested teas improved and ameliorated all the biochemical and microscopic observations by restricting cellular DNA damage and protecting uterine and ovarian tissues from oxidative injury and cell death. The best improvement was observed in the matcha administered group.

Production of pharmaceutical active recombinant globular adiponectin as a secretory protein in Withania Somnifera hairy root culture

Among various in vitro plant culture systems, hairy root systems seem to be one of the most appealing methods of recombinant protein production due to their advantages in combining both whole-plant cultivation and suspension cell culture platform. This is a report on production and secretion of a recombinant pharmaceutically active protein from hairy roots cultures of Withania somnifera to improve the economic potential of this plant for the production pharmaceutical compounds. In this study, we selected and synthesized a codon-optimized globular adiponectin (gAd) gene with a calreticulin signal peptide and cloned the sequence into a plant expression binary vector containing a nptII gene as a selectable marker gene. The transgenic hairy roots were produced by Agrobacterium rhizogenes-mediated transformation protocol developed by our group. Among ten established nptII positive hairy roots lines, six colons significantly accumulated gAd protein in the biomass and extracellular medium. The presence of gAd was confirmed by western blot analysis of root extracts. The maximum level of hairy root biomass, growth rate (GR), intra- and extracellular gAd expressions were obtained after 25-26 days of culture on MS medium. The maximum level of intra- and extracellular gAd proteins were found to be 15.19 μg/gFW and 215.7 μg/L, respectively, which resulted in a significant decrease in the amount of intra- and extracellular withanolide A and withaferin A production. The addition of PVP, KNO3 and NaCl significantly increased the level of extracellular gAd by approximately 13 folds. This improvement could significantly increase the amount of intra- and extracellular withanolide A and withaferin A production, too. The recombinant gAd produced from W. somnifera is functional as proved by induction the phosphorylation of ACC in C2C12 muscle cells, as its functional amount was 5.1-fold more than gAd produced from E. coli and 45 % lower than CHO cells.

WRKY1-mediated regulation of tryptophan decarboxylase in tryptamine generation for withanamide production in Withania somnifera (Ashwagandha)

WsWRKY1-mediated transcriptional modulation of Withania somnifera tryptophan decarboxylase gene (WsTDC) helps to regulate fruit-specific tryptamine generation for production of withanamides. Withania somnifera is a highly valued medicinal plant. Recent demonstration of novel indolyl metabolites called withanamides in its fruits (berries) prompted us to investigate its tryptophan decarboxylase (TDC), as tryptophan is invariably a precursor for indole moiety. TDC catalyzes conversion of tryptophan into tryptamine, and the catalytic reaction constitutes a committed metabolic step for synthesis of an array of indolyl metabolites. The TDC gene (WsTDC) was cloned from berries of the plant and expressed in E. coli. The recombinant enzyme was purified and characterized for its catalytic attributes. Catalytic and structural aspects of the enzyme indicated its regulatory/rate-limiting significance in generation of the indolyl metabolites. Novel tissue-wise and developmentally differential abundance of WsTDC transcripts reflected its preeminent role in withanamide biogenesis in the fruits. Transgenic lines overexpressing WsTDC gene showed accumulation of tryptamine at significantly higher levels, while lines silenced for WsTDC exhibited considerably depleted levels of tryptamine. Cloning and sequence analysis of promoter of WsTDC revealed the presence of W-box in it. Follow-up studies on isolation of WsWRKY1 transcription factor and its overexpression in W. somnifera revealed that WsTDC expression was substantially induced by WsWRKY1 resulting in overproduction of tryptamine. The study invokes a key role of TDC in regulating the indolyl secondary metabolites through enabling elevated flux/supply of tryptamine at multiple levels from gene expression to catalytic attributes overall coordinated by WsWRKY1. This is the first biochemical, molecular, structural, physiological and regulatory description of a fruit-functional TDC.

Berry transcriptome: insights into a novel resource to understand development dependent secondary metabolism in Withania somnifera (Ashwagandha)

Withania somnifera (Ashwagandha) is considered as Rasayana in Indian systems of medicine. This study reports a novel transcriptome of W. somnifera berries, with high depth, quality and coverage. Assembled and annotated transcripts for nearly all genes related with the withanolide biosynthetic pathway were obtained. Tissue-wide gene expression analysis reflected almost similar definitions for the terpenoid pathway in leaf, root and berry tissues with relatively higher abundance of transcripts linked to steroid, phenylpropanoid metabolism as well as flavonoid metabolism in berries. The metabolome map generated from the data embodied transcripts from 143 metabolic pathways connected together and mediated collectively by about 1792 unique enzyme functions specific to berry, leaf and root tissues, respectively. Transcripts specific to cytochrome p450 (CYP450), methyltransferases and glycosyltransferases were distinctively located in a tissue specific manner and exhibited a complex network. Significant distribution of transcription factor genes such as MYB, early light inducible protein (ELI), minichromosome maintenance1, agamous, deficiens and serum response factor (MADS) and WRKY etc. was observed, as the major transcriptional regulators of secondary metabolism. Validation of the assembly was ascertained by cloning WsELI, which has a light dependent regulatory role in development. Quantitative expression of WsELI was observed to be considerably modulated upon exposure to abiotic stress and elicitors. Co-relation of over-expression of WsELI, may provide new aspects for the functional role of ELI proteins in plants linked to secondary metabolism. The study offers the first comprehensive and comparative evaluation of W. somnifera transcriptome data between the three tissues and across other members of Solanaceae (Nicotiana, Solanum and Capsicum) with respect to major pathways and their metabolome regulation.

Virus-Induced Gene Silencing for Functional Genomics in Withania somnifera, an Important Indian Medicinal Plant

Virus-induced gene silencing (VIGS) has emerged as a fast and efficient reverse and forward genetics tool to study gene function in model plants as well as in agriculturally important plants. In addition, VIGS approach has been successfully used to provide insights into the role of several genes and regulators involved in plant secondary metabolism. Ashwagandha (Withania somnifera) is an important Indian medicinal plant that accumulates pharmacologically important triterpenoid steroidal lactones, which are collectively termed as withanolides. W. somnifera being a highly recalcitrant plant for genetic transformation, Tobacco rattle virus (TRV)-mediated VIGS was established by our group to facilitate understanding of withanolides' pathway. Here, we describe a detailed procedure to carry out VIGS for gene function studies in W. somnifera.

Neuroprotective Effect of CR-777, a Glutathione Derivative of Withaferin A, Obtained through the Bioconversion of Withania somnifera (L.) Dunal Extract by the Fungus Beauveria bassiana

The bioconversion of Withania somnifera extract by the fungus Beauveria bassiana leads to cysteine and glutathione derivatives of withaferin A at the C-6 position. The compounds were purified and fully characterized by 1D-NMR, 2D-NMR, and HRMS analysis. The glutathione derivative CR-777 was evaluated as a neuroprotective agent from damage caused by different neurotoxins mimicking molecular symptoms in Parkinson´s disease (PD), including 1-methyl-4-phenylpyridinium (MPP+), 6-hydroxydopamine (6-OHDA), and α-synuclein (α-Syn). CR-777, at nanomolar concentrations, protected dopaminergic and cortical neurons. In 6-OHDA-treated neurons, CR-777 increased cell survival and neurite network and decreased the expression of α-Syn. Using specific inhibitors of cell toxicity signaling pathways and specific staining experiments, the observed role of CR-777 seemed to involve the PI3K/mTOR pathway. CR-777 could be considered as a protective agent against a large panel of neuronal stressors and was engaged in further therapeutic development steps.

Jasmonate responsive transcription factor WsMYC2 regulates the biosynthesis of triterpenoid withanolides and phytosterol via key pathway genes in Withania somnifera (L.) Dunal

Functional characterization of WsMYC2 via artificial microRNA mediated silencing and transient over-expression displayed significant regulatory role vis-à-vis withanolides and stigmasterol biosyntheses in Withania somnifera. Further, metabolic intensification corroborated well with higher expression levels of putative pathway genes. Additionally, copious expression of WsMYC2 in response to exogenous elicitors resulted in enhanced withanolides production. Withania somnifera, a high value multipurpose medicinal plant, is a rich reservoir of structurally diverse and biologically active triterpenoids known as withanolides. W. somnifera has been extensively pursued vis-à-vis pharmacological and chemical studies. Nonetheless, there exists fragmentary knowledge regarding the metabolic pathway and the regulatory aspects of withanolides biosynthesis. Against this backdrop, a jasmonate-responsive MYC2 transcription factor was identified and functionally characterized from W. somnifera. In planta transient over-expression of WsMYC2 showed significant enhancement of mRNA transcript levels which corroborated well with the enhanced content of withanolides and stigmasterol. Further, a comparative analysis of expression levels of some of the genes of triterpenoid pathway viz. WsCAS, WsCYP85A, WsCYP90B and WsCYP710A in corroboration with the over-expression and silencing of WsMYC2 suggested its positive influence on their regulation. These corroboratory approaches suggest that WsMYC2 has cascading effect on over-expression of multiple pathway genes leading to the increased triterpenoid biosynthesis in infiltered plants. Further, the functional validation of WsMYC2 was carried out by artificial micro-RNA mediated silencing. It resulted in significant reduction of withanolides and stigmasterol levels, indicative of crucial role of WsMYC2 in the regulation of their biosyntheses. Taken together, these non-complementary approaches provided unambiguous understanding of the regulatory role of WsMYC2 in context to withanolides and stigmasterol biosyntheses. Furthermore, the upstream promoter of WsMYC2 presented several cis-regulatory elements primarily related to phytohormone responsiveness. WsMYC2 displayed inducible nature in response to MeJA. It had substantial influence on the higher expression of WsMYC2 which was in consonance with enhanced accumulation of withanolides.

ROS management is mediated by ascorbate-glutathione-α-tocopherol triad in co-ordination with secondary metabolic pathway under cadmium stress in Withania somnifera

Being static, plants are frequently exposed to various essential and non-essential heavy metals from the surroundings. This exposure results in considerable ROS generation leading to oxidative stress, the primary response of the plants under heavy metal stress. Withania somnifera is a reputed Indian medicinal plant in Ayurveda, having various pharmacological activities due to the presence of withanolides. The present study deals with the understanding endurance of oxidative stress caused by heavy metal exposure and its management through antioxidant partners in synchronization with secondary metabolites in W. somnifera. The quantitative assessment of enzymatic/non-enzymatic antioxidants revealed significant participation of ascorbate-glutathione-α-tocopherol triad in ROS management. Higher activities of glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) resulted in glutathione and ascorbate accumulation. In addition, superoxide dismutase (SOD), glutathione peroxidase (GPX) and peroxidase (POD) were contributed considerably in ROS homeostasis maintenance. In-situ localization and assays related to ROS generation/scavenging revealed key management of ROS status under Cd stress. Higher antioxidative and reducing power activity attributed to the tolerance capability to the plant. Increased expression of withanolide biosynthetic pathway genes such as WsHMGR, WsDXS, WsDXR and WsCAS correlated with enhanced withanolides. The present study indicated the crucial role of the ascorbate-glutathione-α-tocopherol triad in co-ordination with withanolide biosynthesis in affording the oxidative stress, possibly through a cross-talk between the antioxidant machinery and secondary metabolite biosynthesis. The knowledge may be useful in providing the guidelines for developing abiotic stress resistance in plants using conventional and molecular approaches.

RNAi of Sterol Methyl Transferase1 Reveals its Direct Role in Diverting Intermediates Towards Withanolide/Phytosterol Biosynthesis in Withania somnifera

The medicinal properties of Ashwagandha (Withania somnifera) are accredited to a group of compounds called withanolides. 24-Methylene cholesterol is the intermediate for sterol biosynthesis and a proposed precursor of withanolide biogenesis. However, conversion of 24-methylene cholesterol to withaferin A and other withanolides has not yet been biochemically dissected. Hence, in an effort to fill this gap, an important gene, encoding S-adenosyl l-methionine-dependent sterol-C24-methyltransferase type 1 (SMT1), involved in the first committed step of sterol biosynthesis, from W. somnifera was targeted in the present study. Though SMT1 has been characterized in model plants such as Nicotiana tabacum and Arabidopsis thaliana, its functional role in phytosterol and withanolide biosynthesis was demonstrated for the first time in W. somnifera. Since SMT1 acts at many steps preceding the withanolide precursor, the impact of this gene in channeling of metabolites for withanolide biosynthesis and its regulatory nature was illustrated by suppressing the gene in W. somnifera via the RNA interference (RNAi) approach. Interestingly, down-regulation of SMT1 in W. somnifera led to reduced levels of campesterol, sitosterol and stigmasterol, with an increase of cholesterol content in the transgenic RNAi lines. In contrast, SMT1 overexpression in transgenic N. tabacum enhanced the level of all phytosterols except cholesterol, which was not affected. The results established that SMT1 plays a crucial role in W. somnifera withanolide biosynthesis predominantly through the campesterol and stigmasterol routes.

Elucidating the active interaction mechanism of phytochemicals withanolide and withanoside derivatives with human serum albumin

Withania somnifera (Ashwagandha) is an efficient medicinal plant known in Ayurveda and Chinese medicine since ancient times, whose extracts are consumed orally as food supplement or as a health tonic owing to its several restorative properties for various CNS disorders, inflammation, tumour, stress, rheumatism etc. In this study, we have analyzed the binding interaction of four derivatives of Withania somnifera (Withanolide A, Withanolide B, Withanoside IV and Withanoside V) with HSA because of their important pharmacological properties. To unravel the binding between derivatives of Withania somnifera and HSA, fluorescence spectroscopy was used. Binding studies were further studied by molecular docking and dynamics and results confirmed greater stability upon binding of derivatives with HSA. Circular dichroism data illustrated change in the secondary structure of protein upon interaction with these derivatives, particularly the helical structure was increased and β-sheets and random coils were decreased. Furthermore, morphological and topological changes were observed using AFM and TEM upon binding of ligands with HSA indicating that HSA-withnoside/withanolide complexes were formed. All the results cumulatively demonstrate strong binding of withanosides and withanolides derivatives with serum albumin, which should further be explored to study the pharmacokinetics and pharmacodynamics of these derivatives.

Modulations in primary and secondary metabolic pathways and adjustment in physiological behaviour of Withania somnifera under drought stress

In general medicinal plants grown under water limiting conditions show much higher concentrations of secondary metabolites in comparison to control plants. In the present study, Withania somnifera plants were subjected to water stress and data related to drought tolerance phenomenon was collected and a putative mechanistic concept considering growth responses, physiological behaviour, and metabolite content and gene expression aspects is presented. Drought induced metabolic and physiological responses as well as drastic decrease in CO₂ uptake due to stomatal limitations. As a result, the consumption of reduction equivalents (NADPH²⁺) for CO₂ assimilation via the calvin cycle declines significantly resulting in the generation of a large oxidative stress and an oversupply of antioxidant enzymes. Drought also results in the shifting of metabolic processes towards biosynthetic activities that consume reduction equivalents. Thus, biosynthesis of reduced compounds (isoprenoids, phenols and alkaloids) is enhanced. The dynamics of various metabolites have been discussed in the light of gene expression analysis of control and drought treated leaves. Gene encoding enzymes of pathways leading to glucose, fructose and fructan production, conversion of triose phosphates to hexoses and hexose phosphorylation were up-regulated in the drought stressed leaves. The down-regulated Calvin cycle genes were co-ordinately regulated with the down-regulation of chloroplast triosephosphate/phosphate translocator, cytoplasmic fructose-1,6-bisphosphate aldolase and fructose bisphosphatase. Expression of gene encoding Squalene Synthase (SQS) was highly upregulated under drought stress which is responsible for the diversion of carbon flux towards withanolides biosynthesis from isoprenoid pathway.

Organic cultivation of Ashwagandha with improved biomass and high content of active Withanolides: Use of Vermicompost

Withania somnifera (Ashwagandha) has recently been studied extensively for its health-supplementing and therapeutic activities against a variety of ailments. Several independent studies have experimentally demonstrated pharmaceutical potential of its active Withanolides, Withaferin A (Wi-A), Withanone (Wi-N) and Withanolide A (Wil-A). However, to promote its use in herbal industry, an environmentally sustainable cultivation and high yield are warranted. In modern agriculture strategies, there has been indiscriminate use of chemical fertilizers to boost the crop-yield, however the practice largely ignored its adverse effect on the quality of soil and the environment. In view of these, we attempted to recruit Vermicompost (Vcom, 20-100%) as an organic fertilizer of choice during the sowing and growing phases of Ashwagandha plants. We report that (i) pre-soaking of seeds for 12 h in Vermicompost leachate (Vcom-L) and Vermicompost tea (Vcom-T) led to higher germination, (ii) binary combination of pre-soaking of seeds and cultivation in Vcom (up to 80%) resulted in further improvement both in germination and seedling growth, (iii) cultivated plants in the presence of Vcom+Vcom-L showed higher leaf and root mass, earlier onset of flowering and fruiting and (iv) leaves from the Vcom+Vcom-L cultivated plants showed higher level of active Withanolides, Withanone (Wi-N), Withanolide A (Wil-A) and Withaferin A (Wi-A) and showed anticancer activities in cell culture assays. Taken together, we report a simple and inexpensive method for improving the yield and pharmaceutical components of Ashwagandha leaves.

HMG-CoA reductase from Camphor Tulsi (Ocimum kilimandscharicum) regulated MVA dependent biosynthesis of diverse terpenoids in homologous and heterologous plant systems

Ocimum kilimandscharicum is unique in possessing terpenoids whereas other Ocimum species are renowned for phenylpropanoids as major constituents of essential oil. The key enzyme of MVA/terpenoid metabolic pathway viz 3-hydroxy-3-methylglutaryl Co-A reductase (OkHMGR) of 1.7-Kb ORF encoding ~60-kDa protein was cloned from O. kilimandscharicum and its kinetic characteristics revealed the availability of HMG-CoA as a control point of MVA-pathway. Transcript profiling of the OkHMGR elucidated tissue-specific functions of the gene in flower and leaf tissues in accumulation of terpenoidal essential oil. OkHMGR was differentially regulated in response to exposure to methyl-jasmonate, salicylic-acid, and stress conditions such-as salt and temperature stress, demonstrating its key role in managing signaling and stress-responses. To elucidate its functional role, OkHMGR was transiently over-expressed in homologous and heterologous plants such as O. sanctum, O. basilicum, O. gratissimum, Withania somnifera and Artemisia annua. The over-expression and inhibition dual strategy revealed that the additional OkHMGR in-planta could afford endogenous flow of isoprenoid units towards synthesis of terpenoids. The present study provides in-depth insight of OkHMGR in regulation of biosynthesis of non-plastidal isoprenoids. This is first report on any gene of MVA/isoprenoid pathway from under-explored Camphor Tulsi belonging to genus Ocimum. Studies also suggested that OkHMGR could be a potential tool for attempting metabolic engineering for enhancing medicinally important terpenoidal metabolites in plants.

Transcription factor repertoire in Ashwagandha (Withania somnifera) through analytics of transcriptomic resources: Insights into regulation of development and withanolide metabolism

Transcription factors (TFs) are important regulators of cellular and metabolic functions including secondary metabolism. Deep and intensive RNA-seq analysis of Withania somnifera using transcriptomic databases provided 3532 annotated transcripts of transcription factors in leaf and root tissues, belonging to 90 different families with major abundance for WD-repeat (174 and 165 transcripts) and WRKY (93 and 80 transcripts) in root and leaf tissues respectively, followed by that of MYB, BHLH and AP2-ERF. Their detailed comparative analysis with Arabidopsis thaliana, Capsicum annum, Nicotiana tabacum and Solanum lycopersicum counterparts together gave interesting patterns. However, no homologs for WsWDR representatives, LWD1 and WUSCHEL, were observed in other Solanaceae species. The data extracted from the sequence read archives (SRA) in public domain databases were subjected to re-annotation, re-mining, re-analysis and validation for dominant occurrence of WRKY and WD-repeat (WDR) gene families. Expression of recombinant LWD1 and WUSCHEL proteins in homologous system led to enhancements in withanolide content indicating their regulatory role in planta in the biosynthesis. Contrasting expression profiles of WsLWD1 and WsWUSCHEL provided tissue-specific insights for their participation in the regulation of developmental processes. The in-depth analysis provided first full-spectrum and comparative characteristics of TF-transcripts across plant species, in the perspective of integrated tissue-specific regulation of metabolic processes including specialized metabolism.

Exogenous application of IAA alleviates effects of supplemental ultraviolet-B radiation in the medicinal plant Withania somnifera Dunal

Supplemental (s)-UV-B radiation has adverse effects on the majority of plants. The present study was conducted to evaluate the effects of exogenous application of the growth hormone indole acetic acid (IAA) on various morphological, physiological and biochemical characteristics of Withania somnifera, an indigenous medicinal plant, subjected to s-UV-B. The s-UV-B-treated plants received ambient + 3.6 kJm^-2 ·day^-1 biologically effective UV-B, and IAA was applied at two doses (200 and 400 ppm) to s-UV-B-exposed plants. The plant was forced to compromise its growth, development and photosynthetic patterns to survive under s-UV-B by increasing concentrations of secondary metabolites and antioxidants (thiol, proline, ascorbic acid, α-tocopherol, ascorbate peroxidase, catalase, glutathione reductase, peroxidase, polyphenol oxidase, superoxide dismutase) to counteract oxidative stress. Increases in secondary metabolites were evidenced as increased activity of phenylpropanoid pathway enzymes: phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, 4-coumarate CoA ligase, chalcone isomerase and dihydroflavonol reductase. Application of different IAA doses reversed the detrimental effects of s-UV-B on W. somnifera by improving growth and photosynthesis and reducing concentrations of secondary metabolites and non-enzymatic antioxidants. Antioxidant enzymes, however, had a synergistic effect on s-UV-B treatment and IAA application. The effects of s-UV-B on W. somnifera are ameliorated to varying degrees upon exogenous IAA application, and synergistic enhancement of antioxidant enzymes under s-UV-B+IAA treatment might be responsible for the partial recuperation of growth and plant protein content, as a UV-B-exposed plant is forced to allocate most of its photosynthate towards production of enzymes related to antioxidant defence.

A WRKY transcription factor from Withania somnifera regulates triterpenoid withanolide accumulation and biotic stress tolerance through modulation of phytosterol and defense pathways

Withania somnifera produces pharmacologically important triterpenoid withanolides that are derived via phytosterol pathway; however, their biosynthesis and regulation remain to be elucidated. A jasmonate- and salicin-inducible WRKY transcription factor from W. somnifera (WsWRKY1) exhibiting correlation with withaferin A accumulation was functionally characterized employing virus-induced gene silencing and overexpression studies combined with transcript and metabolite analyses, and chromatin immunoprecipitation assay. WsWRKY1 silencing resulted in stunted plant growth, reduced transcripts of phytosterol pathway genes with corresponding reduction in phytosterols and withanolides in W. somnifera. Its overexpression elevated the biosynthesis of triterpenoids in W. somnifera (phytosterols and withanolides), as well as tobacco and tomato (phytosterols). Moreover, WsWRKY1 binds to W-box sequences in promoters of W. somnifera genes encoding squalene synthase and squalene epoxidase, indicating its direct regulation of triterpenoid pathway. Furthermore, while WsWRKY1 silencing in W. somnifera compromised the tolerance to bacterial growth, fungal infection, and insect feeding, its overexpression in tobacco led to improved biotic stress tolerance. Together these findings demonstrate that WsWRKY1 has a positive regulatory role on phytosterol and withanolides biosynthesis, and defense against biotic stress, highlighting its importance as a metabolic engineering tool for simultaneous improvement of triterpenoid biosynthesis and plant defense.

Sterol glycosyltransferases required for adaptation of Withania somnifera at high temperature

Heat is a major environmental stress factor that confines growth, productivity, and metabolism of plants. Plants respond to such unfavorable conditions through changes in their physiological, biochemical and developmental processes. Withania somnifera, an important medicinal plant, grows in hot and dry conditions, however, molecular mechanisms related to such adaptive properties are not known. Here, we elucidated that members of the sterol glycosyltransferases (SGT) gene family play important roles in the survival of W. somnifera under adverse conditions through maintaining the integrity of the membrane. SGTs are enzymes involved in sterol modifications and participate in metabolic flexibility during stress. Silencing of WsSGT members, for instance WsSGTL1, WsSGTL2 and WsSGTL4, was inimical for important physiological parameters, such as electron transport rate, photochemical quantum yield, acceptor side limitation, non-photochemical quenching (NPQ), Fv/Fm and net photosynthetic rate, whereas stomatal conductance, transpiration rate and dark respiration rates (Rds) were increased. Decreased NPQ and increased Rds helped to generate significant amount of ROS in the Wsamisgt lines. After heat stress, H₂ O₂ , lipid peroxidation and nitric oxide production increased in the Wsamisgt lines due to high ROS generation. The expression of HSPs in Wsamisgt lines might be involved in regulation of physiological processes during stress. We have also observed increased proline accumulation which might be involved in restricting water loss in the Wsamisgt lines. Taken together, our observations revealed that SGTL enzyme activity is required to maintain the internal damages of the cell against high temperature by maintaining the sterol vs sterol glycosides ratio in the membranes of W. somnifera.

Comparative study of withanolide production and the related transcriptional responses of biosynthetic genes in fungi elicited cell suspension culture of Withania somnifera in shake flask and bioreactor

Ashwagandha (Withania somnifera) is one of the most reputed medicinal plants in the traditional medicinal system. In this study, cell suspension culture of W. somnifera was elicited with cell homogenates of fungi (A. alternata, F. solani, V. dahliae and P. indica) in shake flask and the major withanolides like withanolide A, withaferin A and withanone were analysed. Simultaneously expression levels of key pathway genes from withanolides biosynthetic pathways were also checked via quantitative PCR in shake flask as well as in bioreactor. The results show that highest gene expression of 10.8, 5.8, 4.9, and 3.3 folds were observed with HMGR among all the expressed genes in cell suspension cultures with cell homogenates of 3% P. indica, 5% V. dahliae, 3% A. alternata and 3% F. solani, respectively, in comparison to the control in shake flask. Optimized concentration of cell homogenate of P. indica (3% v/v) was added to the growing culture in 5.0-l bioreactor under optimized up-scaling conditions and harvested after 22 days. The genes of MVA, MEP and withanolides biosynthetic pathways like HMGR, SS, SE, CAS, FPPS, DXR and DXS were up-regulated by 12.5, 4.9, 2.18, 4.65, 2.34, 1.89 and 1.4 folds, respectively in bioreactor. The enhancement of biomass (1.13 fold) and withanolides [withanolide A (1.7), withaferin A (1.5), and withanone (1.5) folds] in bioreactor in comparison to shake flask was also found to be in line with the up-regulation of genes of withanolide biosynthetic pathways.

Metabolite Profiling in Withania somnifera Roots Hydroalcoholic Extract Using LC/MS, GC/MS and NMR Spectroscopy

Ashwagandha (Withania somnifera) is a very well-known herbal medicine and it was well studied for its active metabolites throughout the World. Although, nearly 40 withanolides were isolated from W. somnifera root extract, still there is remaining unidentified metabolites due to very low abundance and geographical variation. Advanced separation technology with online identification by mass and nuclear magnetic resonance (NMR) are nowadays used to find out the new compounds in the crude herbal extract. This article described the metabolite profiling of ashwagandha root hydroalcoholic extract using ultra-performance liquid chromatography coupled with a positive ion electrospray ionization tandem mass spectrometry through gas chromatography mass spectrometry (GC/MS) and NMR spectroscopy. A total of 43 possible withanolides was identified and proposed their structures based on the mass of molecular and fragment ions. GC/MS and NMR analysis indicated the presence of several known withanolides including withaferin A, withanolide D, withanoside IV or VI, withanolide sulfoxide, etc. To the best of our knowledge, dihydrowithanolide D at m/z 473 (t_R 7.86 min) and ixocarpalactone A at m/z 505 (t_R 8.43 min) were first time identified in the ashwagandha root hydroalcoholic extract. The current study that described the identification of withanolides with summarized literature review might be helpful for designing the experiment to identify of the new chemical constituents in Withania species.

Virus-induced gene silencing of Withania somnifera squalene synthase negatively regulates sterol and defence-related genes resulting in reduced withanolides and biotic stress tolerance

Withania somnifera (L.) Dunal is an important Indian medicinal plant that produces withanolides, which are triterpenoid steroidal lactones having diverse biological activities. To enable fast and efficient functional characterization of genes in this slow-growing and difficult-to-transform plant, a virus-induced gene silencing (VIGS) was established by silencing phytoene desaturase (PDS) and squalene synthase (SQS). VIGS of the gene encoding SQS, which provides precursors for triterpenoids, resulted in significant reduction of squalene and withanolides, demonstrating its application in studying withanolides biosynthesis in W. somnifera leaves. A comprehensive analysis of gene expression and sterol pathway intermediates in WsSQS-vigs plants revealed transcriptional modulation with positive feedback regulation of mevalonate pathway genes, and negative feed-forward regulation of downstream sterol pathway genes including DWF1 (delta-24-sterol reductase) and CYP710A1 (C-22-sterol desaturase), resulting in significant reduction of sitosterol, campesterol and stigmasterol. However, there was little effect of SQS silencing on cholesterol, indicating the contribution of sitosterol, campesterol and stigmasterol, but not of cholesterol, towards withanolides formation. Branch-point oxidosqualene synthases in WsSQS-vigs plants exhibited differential regulation with reduced CAS (cycloartenol synthase) and cycloartenol, and induced BAS (β-amyrin synthase) and β-amyrin. Moreover, SQS silencing also led to the down-regulation of brassinosteroid-6-oxidase-2 (BR6OX2), pathogenesis-related (PR) and nonexpressor of PR (NPR) genes, resulting in reduced tolerance to bacterial and fungal infection as well as to insect feeding. Taken together, SQS silencing negatively regulated sterol and defence-related genes leading to reduced phytosterols, withanolides and biotic stress tolerance, thus implicating the application of VIGS for functional analysis of genes related to withanolides formation in W. somnifera leaves.

Micromorphology, histochemistry and ultrastructure of the foliar trichomes of Withania somnifera (L.) Dunal (Solanaceae)

The leaves of Withania somnifera contained four morphologically distinct trichome types: glandular capitate, non-glandular dendritic (branched), non-glandular bicellular and non-glandular multicellular trichomes. Major phytochemical compounds present within glandular and non-glandular trichomes were alkaloids and phenolic compounds. The aim of this study was to characterize the micromorphology of the foliar trichomes of Withania somnifera as well as to elucidate the location and composition of the secretory products. Trichome density and length was also determined in three developmental stages of the leaves. Light microscopy and scanning electron microscopy showed the presence of four morphologically distinct trichome types: glandular capitate, non-glandular dendritic, non-glandular bicellular and non-glandular multicellular. The dendritic trichomes exhibited cuticular warts which are involved in the "Lotus-Effect". Glandular capitate and non-glandular dendritic trichomes were aggregated on the mid-vein of young and mature leaves, possibly to protect underlying vasculature. Histochemical staining also revealed the presence of two major classes of phytochemical compounds that are of medicinal importance, i.e. alkaloids and phenolic compounds. These compounds are used to treat a wide variety of ailments and also act as chemical deterrents in plants. The results of this study explain possible roles of four morphologically distinct trichome types based on their morphology, foliar distribution and content.

Withaferin A attenuates lipopolysaccharide-induced acute lung injury in neonatal rats

Withaferin A (WFA) is an active compound from Withania somnifera and has been reported to exhibit a variety of pharmacological activities such as anti&mdash;inflammatory, immunomodulatory and anti&mdash;tumor properties. In the present study, we investigated the potential protective role of WFA on acute lung injury in neonatal rats induced by lipopolysaccharide (LPS). We found that WFA significantly attenuated the pathological changes of lungs induced by LPS injection. Administration with WFA obviously decreased pulmonary neutrophil infiltration accompanied with decreased MPO concentrations. WFA also reduced the expression of pro&mdash;inflammatory cytokines including MIP&mdash;2, TNF&mdash;&#945;, IL&mdash;1&#946; and IL&mdash;6. Meanwhile, the expression levels of anti&mdash;inflammatory mediators such as TGF&mdash;&#946;1 and IL&mdash;10 were significantly increased following WFA administration. Moreover, WFA protected LPS&mdash;treated rats from oxidative damage via up&mdash;regulation of TBARS and H2O2 concentrations and down&mdash;regulation of ROS contents. Taken together, the present study demonstrated that WFA administration attenuated LPS&mdash;induced lung injury through inhibition of inflammatory responses and oxidative stress.

Metabolic shift from withasteroid formation to phenylpropanoid accumulation in cryptogein-cotransformed hairy roots of Withania somnifera (L.) Dunal

Cotransformed hairy roots containing a gene that encodes a fungal elicitor protein, β-cryptogein, were established in Withania somnifera, a medicinal plant widely used in Indian systems of medicine. To find out whether β-cryptogein protein endogenously elicits the pathway of withasteroid biosynthesis, withaferin A and withanolide A contents along with transcript accumulation of farnesyl pyrophosphate (FPP) synthase, 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), and sterol glycosyltransferase (SGT) were analyzed in both cryptogein-cotransformed and normal hairy roots of W. somnifera. It was observed that the withaferin A and withanolide A contents were drastically higher in normal hairy roots than cryptogein-cotransformed ones. Similar trends were also observed on the levels of transcript accumulation. Subsequently, the enzyme activity of phenylalanine ammonia lyase (PAL), one of the key enzymes of phenylpropanoid pathway, was measured in both cryptogein-cotransformed and normal hairy roots of W. somnifera along with the levels of PAL transcript accumulation. Upliftment of PAL activity was observed in cryptogein-cotransformed hairy roots as compared to the normal ones, and the PAL expression also reflected a similar trend, i.e., enhanced expression in the cryptogein-cotransformed lines. Upliftment of wall-bound ferulic acid accumulation was also observed in the cryptogein-cotransformed lines, as compared to normal hairy root lines. Thus, the outcome of the above studies suggests a metabolic shift from withanolide accumulation to phenylpropanoid biosynthesis in cryptogein-cotransformed hairy roots of W. somnifera.

Expression of important pathway genes involved in withanolides biosynthesis in hairy root culture of Withania somnifera upon treatment with Gracilaria edulis and Sargassum wightii

The investigation of seaweeds, Gracilaria edulis and Sargassum wightii extracts was carried out for the estimation of growth characteristics and major withanolides production in hairy root culture of Withania somnifera. The extract of G. edulis (50%) in MS liquid basal medium enabled maximum production of dry biomass (5.46 g DW) and withanolides contents (withanolide A 5.23 mg/g DW; withaferin A 2.24 mg/g DW and withanone 4.83 mg/g DW) in hairy roots after 40 days of culture with 48 h contact time. The obtained withanolides contents were significantly higher (2.32-fold-2.66-fold) in hairy root culture when compared to the control. RT PCR analysis of important pathway genes such as SE, SS, HMGR and FPPS exhibited substantial higher expression upon the seaweed extracts treatment in hairy root culture. This experiment would paw a platform for withanolides production in hairy root culture with the influence of sea weed extracts for pharmaceutical companies in the future.

WsMAGO2, a duplicated MAGO NASHI protein with fertility attributes interacts with MPF2-like MADS-box proteins

WsMAGO2 a duplicated protein in Withania through interactions with MPF2-like proteins affects male fertility by producing fewer flowers and aborted non-viable pollens/seeds regulated by anther-specific GAATTTGTGA motif. The MAGO NASHIs are highly conserved genes that encode proteins known to be involved in RNA physiology and many other developmental processes including germ cell differentiation in animals. However, their structural and functional implications in plants as fertility function proteins remained fragmented. MAGO (shorter name of MAGO NASHI) proteins form heterodimers with MPF2-like MADS-box proteins which are recruited in calyx identity and male fertility in Solanaceous plants. Four MAGO genes namely WsMAGO1 and WsMAGO2 and TaMAGO1 and TaMAGO2 were isolated from Withania somnifera and Tubocapsicum anomalum, respectively. These genes have duplicated probably due to whole genome duplication event. Dysfunction of WsMAGO2 through double-stranded RNAi in Withania revealed suppression of RNA transcripts, non-viable pollens, fewer flowers and aborted non-viable seeds in the developing berry suggesting a role of this protein in many traits particularly male fertility. WsMAGO2 flaunted stronger yeast 2-hybrid interactions with MPF2-like proteins WSA206, WSB206 and TAB201 than other MAGO counterparts. The native transcripts of WsMAGO2 culminated in stamens and seed-bearing berries though other MAGO orthologs also exhibited expression albeit at lower level. Coding sequences of the two orthologs are highly conserved, but they differ substantially in their upstream promoter regions. Remarkably, WsMAGO2 promoter is enriched with many anther-specific cis-motifs common in fertility function genes promoters. Among them, disruption of GAATTTGTGA abolished YFP/GUS gene expression in anthers alluding towards its involvement in regulating expression of MAGO in anther. Our findings support a possible recruitment of WsMAGO2 in fertility trait in Withania. These genes have practical application in hybrid production through cytoplasmic male sterility maintenance for enhancement in crops yield.

Free radical scavenging activity and comparative metabolic profiling of in vitro cultured and field grown Withania somnifera roots

Free radical scavenging activity (FRSA), total phenolic content (TPC), and total flavonoid content (TFC) of in vitro cultured and field grown Withania somnifera (Ashwagandha) roots were investigated. Withanolides analysis and comprehensive metabolic profiling between 100% methanol extracts of in vitro and field grown root tissues was performed using high performance thin layer chromatography (HPTLC) and gas chromatography-mass spectrometry (GC-MS), respectively. Significantly higher levels of FRSA, TPC, and TFC were observed in in-vitro cultured roots compared with field grown samples. In addition, 30 day-cultured in vitro root samples (1MIR) exhibited a significantly higher FRSA (IC₅₀ 81.01 μg/mL), TPC (118.91 mg GAE/g), and TFC (32.68 mg CE/g) compared with those in 45 day-cultured samples (1.5MIR). Total of 29 metabolites were identified in in vitro cultured and field grown roots by GC-MS analysis. The metabolites included alcohols, organic acids, purine, pyrimidine, sugars, and putrescine. Vanillic acid was only observed in the in vitro cultured root samples, and higher level of the vanillic acid was observed in 1MIR when compared to 1.5MIR. Therefore, it is suggested that 1MIR might serve as an alternative to field grown roots for the development of medicinal and functional food products.

Combinations of Ashwagandha leaf extracts protect brain-derived cells against oxidative stress and induce differentiation

BACKGROUND

Ashwagandha, a traditional Indian herb, has been known for its variety of therapeutic activities. We earlier demonstrated anticancer activities in the alcoholic and water extracts of the leaves that were mediated by activation of tumor suppressor functions and oxidative stress in cancer cells. Low doses of these extracts were shown to possess neuroprotective activities in vitro and in vivo assays.

METHODOLOGY/PRINCIPAL FINDINGS

We used cultured glioblastoma and neuroblastoma cells to examine the effect of extracts (alcoholic and water) as well as their bioactive components for neuroprotective activities against oxidative stress. Various biochemical and imaging assays on the marker proteins of glial and neuronal cells were performed along with their survival profiles in control, stressed and recovered conditions. We found that the extracts and one of the purified components, withanone, when used at a low dose, protected the glial and neuronal cells from oxidative as well as glutamate insult, and induced their differentiation per se. Furthermore, the combinations of extracts and active component were highly potent endorsing the therapeutic merit of the combinational approach.

CONCLUSION

Ashwagandha leaf derived bioactive compounds have neuroprotective potential and may serve as supplement for brain health.

Effect of iron stress on Withania somnifera L.: antioxidant enzyme response and nutrient elemental uptake of in vitro grown plants

In the present study the response of antioxidant enzyme activities and the level of expression of their corresponding genes on bioaccumulation of iron (Fe) were investigated. In vitro germinated Withania somnifera L. were grown in Murashige and Skoog's liquid medium with increasing concentrations (0, 25, 50, 100 and 200 µM) of FeSO4 for 7 and 14 days. Root and leaf tissues analyzed for catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1) and guaiacol peroxidase (GPX, EC 1.11.1.7), have shown an increase in content with respect to exposure time. Isoforms of CAT, SOD and GPX were separated using non-denaturing polyacrylamide gel electrophoresis and observed that the isoenzymes were greatly affected by higher concentrations of Fe. Reverse transcriptase polymerase chain reaction analysis performed by taking three pairs of genes of CAT (RsCat, Catalase1, Cat1) and SOD (SodCp, TaSOD1.2, MnSOD) to find out the differential expression of antioxidant genes under Fe excess. RsCat from CAT and MnSOD from SOD have exhibited high levels of gene expression under Fe stress, which was consistent with the changes of the activity assayed in solution after 7 days of treatment. Analysis by proton induced X-ray emission exhibited an increasing uptake of Fe in plants by suppressing and expressing of other nutrient elements. The results of the present study suggest that higher concentration of Fe causes disturbance in nutrient balance and induces oxidative stress in plant.

Effect of cadmium stress on inductive enzymatic and nonenzymatic responses of ROS and sugar metabolism in multiple shoot cultures of Ashwagandha (Withania somnifera Dunal)

Withania somnifera is one of the most important medicinal plant and is credited with various pharmacological activities. In this study, in vitro multiple shoot cultures were exposed to different concentrations (5-300 μM) of cadmium (Cd) as cadmium sulphate to explore its ability to accumulate the heavy metal ion and its impact on the metabolic status and adaptive responses. The results showed that supplemental exposure to Cd interfered with N, P, and K uptake creating N, P, and K deficiency at higher doses of Cd that also caused stunting of growth, chlorosis, and necrosis. The study showed that in vitro shoots could markedly accumulate Cd in a concentration-dependent manner. Enzymatic activities and isozymic pattern of catalase, ascorbate peroxidase, guaiacol peroxidase, peroxidase, glutathione-S-transferase, glutathione peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase were altered substantially under Cd exposure. Sugar metabolism was also markedly modulated under Cd stress. Various other parameters including contents of photosynthetic pigments, phenolics, tocopherol, flavonoids, reduced glutathione, nonprotein thiol, ascorbate, and proline displayed major inductive responses reflecting their protective role. The results showed that interplay of enzymatic as well as nonenzymatic responses constituted a system endeavor of tolerance of Cd accumulation and an efficient scavenging strategy of its stress implications.

Oral supplementation of standardized extract of Withania somnifera protects against diabetes-induced testicular oxidative impairments in prepubertal rats

Male reproductive dysfunctions and infertility are the common consequences of overt diabetes. Available evidence support oxidative stress to be the underlying mechanism for the manifestation of testicular complications during diabetes. In the present study, we assessed the attenuating effects of Withania somnifera root extract (WS) on diabetes-induced testicular oxidative disturbances in prepubertal rats. Four-week-old prepubertal rats were assigned into nondiabetic control, streptozotocin (STZ)-treated and STZ+WS supplemented (500 mg/kg b.w./d, oral, 15 days) groups. Experimental diabetes was induced by a single intraperitoneal injection of STZ (90 mg/kg b.w). Terminally, all animals were killed, and markers of oxidative stress were determined in the testis cytosol and mitochondrial fraction. Severe hyperglycemia and regression in testis size were apparent in diabetic rats. A decline in antioxidant defenses with subsequent elevation in the generation of reactive oxygen species and lipid peroxidation was discernible in testis cytosol and mitochondria of diabetic prepubertal rats, which was significantly reversed by WS. However, there was partial restoration of glucose-6-phosphate dehydrogenase, lactate dehydrogenase, and 3-beta hydroxysteroid dehydrogenase activities in testis of diabetic prepubertal rats administered with WS. Taken together, data accrued suggest the potential of WS to improve diabetes-induced testicular dysfunctions in prepubertal rats.

Enhanced biosynthesis of withanolides by elicitation and precursor feeding in cell suspension culture of Withania somnifera (L.) Dunal in shake-flask culture and bioreactor

The present study investigated the biosynthesis of major and minor withanolides of Withania somnifera in cell suspension culture using shake-flask culture and bioreactor by exploiting elicitation and precursor feeding strategies. Elicitors like cadmium chloride, aluminium chloride and chitosan, precursors such as cholesterol, mevalonic acid and squalene were examined. Maximum total withanolides detected [withanolide A (7606.75 mg), withanolide B (4826.05 mg), withaferin A (3732.81 mg), withanone (6538.65 mg), 12 deoxy withanstramonolide (3176.63 mg), withanoside IV (2623.21 mg) and withanoside V (2861.18 mg)] were achieved in the combined treatment of chitosan (100 mg/l) and squalene (6 mM) along with 1 mg/l picloram, 0.5 mg/l KN, 200 mg/l L-glutamine and 5% sucrose in culture at 4 h and 48 h exposure times respectively on 28^th day of culture in bioreactor. We obtained higher concentrations of total withanolides in shake-flask culture (2.13-fold) as well as bioreactor (1.66-fold) when compared to control treatments. This optimized protocol can be utilized for commercial level production of withanolides from suspension culture using industrial bioreactors in a short culture period.

WsSGTL1 gene from Withania somnifera, modulates glycosylation profile, antioxidant system and confers biotic and salt stress tolerance in transgenic tobacco

Glycosylation of sterols, catalysed by sterol glycosyltransferases (SGTs), improves the sterol solubility, chemical stability and compartmentalization, and helps plants to adapt to environmental changes. The SGTs in medicinal plants are of particular interest for their role in the biosynthesis of pharmacologically active substances. WsSGTL1, a SGT isolated from Withania somnifera, was expressed and functionally characterized in transgenic tobacco plants. Transgenic WsSGTL1-Nt lines showed an adaptive mechanism through demonstrating late germination, stunted growth, yellowish-green leaves and enhanced antioxidant system. The reduced chlorophyll content and chlorophyll fluorescence with decreased photosynthetic parameters were observed in WsSGTL1-Nt plants. These changes could be due to the enhanced glycosylation by WsSGTL1, as no modulation in chlorophyll biogenesis-related genes was observed in transgenic lines as compared to wildtype (WT) plants. Enhanced accumulation of main sterols like, campesterol, stigmasterol and sitosterol in glycosylated form was observed in WsSGTL1-Nt plants. Apart from these, other secondary metabolites related to plant's antioxidant system along with activities of antioxidant enzymes (SOD, CAT; two to fourfold) were enhanced in WsSGTL1-Nt as compared to WT. WsSGTL1-Nt plants showed significant resistance towards Spodoptera litura (biotic stress) with up to 27 % reduced larval weight as well as salt stress (abiotic stress) with improved survival capacity of leaf discs. The present study demonstrates that higher glycosylation of sterols and enhanced antioxidant system caused by expression of WsSGTL1 gene confers specific functions in plants to adapt under different environmental challenges.

[Hair roots induction and culture of Withania somnifera and its withanolide A synthesis]

Withanolide A is a biologically active secondary metabolite occuring in roots and leaves of Withania somnifera. In the present study, adventitious roots from leaf explants of W. somnifera were induced for the production of withanolide-A by Agrobacterium tumefaciens strain C58C1 to obtain hair roots. Hair roots induction rate reached 30%. The withanolide A was determined by HPLC in different hair roots lines and different parts of W. somnifera. The average content of withanolide A in all hair roots lines were 1.96 times as high as that in wild-plant, the concentration of withanolide A in hair roots (1.783 mg x g(-1) dry weight) were 1.51 times as high as the roots of wild W. somnifera (1.180 mg x g(-1) dry weight), respectively. It is possible to obtain withanolide A from hair roots culture of W. somnifera.