Steroidal lactones from Withania somnifera, an ancient plant for novel medicine

In Vitro Shoot Cultures and Analysis of Steroidal Lactones in Withania coagulans (Stocks) Dunal

Withania coagulans (Stocks) Dunal (Solanaceae), also known as 'Panir Bandh' is an important medicinal plant that is extensively used as a home remedy for several diseases in the Indian subcontinent. The plant possesses specific steroidal lactones known as withanolides which show high level of pharmaceutical activity against a broad spectrum of microorganisms. Natural propagation of the plant occurs through Seed but due to unisexual nature of the flowers; chances of Seed setting are very limited and the plant is on the verge of extinction because of overexploitation and reproductive failure. Plant tissue culture techniques offer opportunities for ex situ conservation and mass multiplication of endangered plant species through micropropagation and also enhancement of in vitro biosynthesis of bioactive compounds. In this chapter we present protocols for the mass multiplication of W. coagulans, assessment of clonal fidelity by RAPD, and estimation of bioactive compounds (withanolides) by thin layer chromatography (TLC) and reverse phase HPLC developed in our laboratory.

RNAi and Homologous Over-Expression Based Functional Approaches Reveal Triterpenoid Synthase Gene-Cycloartenol Synthase Is Involved in Downstream Withanolide Biosynthesis in Withania somnifera

Withania somnifera Dunal, is one of the most commonly used medicinal plant in Ayurvedic and indigenous medicine traditionally owing to its therapeutic potential, because of major chemical constituents, withanolides. Withanolide biosynthesis requires the activities of several enzymes in vivo. Cycloartenol synthase (CAS) is an important enzyme in the withanolide biosynthetic pathway, catalyzing cyclization of 2, 3 oxidosqualene into cycloartenol. In the present study, we have cloned full-length WsCAS from Withania somnifera by homology-based PCR method. For gene function investigation, we constructed three RNAi gene-silencing constructs in backbone of RNAi vector pGSA and a full-length over-expression construct. These constructs were transformed in Agrobacterium strain GV3101 for plant transformation in W. somnifera. Molecular and metabolite analysis was performed in putative Withania transformants. The PCR and Southern blot results showed the genomic integration of these RNAi and overexpression construct(s) in Withania genome. The qRT-PCR analysis showed that the expression of WsCAS gene was considerably downregulated in stable transgenic silenced Withania lines compared with the non-transformed control and HPLC analysis showed that withanolide content was greatly reduced in silenced lines. Transgenic plants over expressing CAS gene displayed enhanced level of CAS transcript and withanolide content compared to non-transformed controls. This work is the first full proof report of functional validation of any metabolic pathway gene in W. somnifera at whole plant level as per our knowledge and it will be further useful to understand the regulatory role of different genes involved in the biosynthesis of withanolides.

Favorable results from the use of herbal and plant products in inflammatory bowel disease: evidence from experimental animal studies

The use of herbal therapy for inflammatory bowel disease is increasing worldwide. The aim of this study was to review the available literature on the efficacy of herbal therapy in experimental colitis. All relevant studies published in Medline and Embase up to June 2015 have been reviewed. The results of bowel histology and serum parameters have been recorded. A satisfactory number of published experimental studies, and a quite large one of both herbal and plant products tested in different studies have been reported. The results showed that in the majority of the studies, herbal therapy reduced the inflammatory activity of experimental colitis and diminished the levels of many inflammatory indices, including serum cytokines and indices of oxidative stress. The most promising plant and herbal products were tormentil extracts, wormwoodherb, Aloe vera, germinated barley foodstuff, curcumin, Boswellia serrata, Panax notoginseng, Ixeris dentata, green tea, Cordia dichotoma, Plantago lanceolata, Iridoidglycosides, and mastic gum. Herbal therapies exert their therapeutic benefit via various mechanisms, including immune regulation, anti-oxidant activity, inhibition of leukotriene B4 and nuclear factor-κB, and antiplatelet activity. Large, double-blind clinical studies assessing these natural substances should be urgently conducted.

Withania somnifera: From prevention to treatment of cancer

The identification of bioactive molecules that have potential to interrupt carcinogenesis continues to garner research interest. In particular, molecules that have dietary origin are most attractive because of their safety, cost-effectiveness and feasibility of oral administration. Nutraceuticals have played an important role in the overall well-being of humans for many years, with or without rigorous evidence backing their health claims. Traditional medicine systems around the world have utilized plants that have medicinal properties for millennia, providing an opportunity for modern day researchers to assess their efficacies against ailments such as cancer. Withania somnifera (WS) is a plant that has been used in Ayurveda (an ancient form of medicine in Asia) and in the recent past, has been demonstrated to have anti-tumorigenic properties in experimental models. While scientific research performed on WS has exploded in the past decade, much regarding the mode of action and molecular targets involved remains unknown. In this review, we discuss the traditional uses of the plant, the experimental evidence supporting its chemopreventive potential as well as roadblocks that need to be overcome in order for WS to be evaluated as a chemopreventive agent in humans.

Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adults

Introduction:

Ashwagandha (Withania somnifera [L.] Dunal) has been traditionally used for various actions ranging from vitalizer, improve endurance and stamina, promote longevity, improve immunity, and male and female fertility. However, clinical studies are needed to prove the clinical efficacy of this herb, especially in cardiovascular endurance and physical performance.

Aims:

This prospective, double-blind, randomized, and placebo-controlled study evaluated the efficacy of Ashwagandha roots extract in enhancing cardiorespiratory endurance and improving the quality of life (QOL) in 50 healthy male/female athletic adults.

Materials and Methods:

Cardiorespiratory endurance was assessed by measuring the oxygen consumption at peak physical exertion (VO₂ max) levels during a 20 m shuttle run test. The World Health Organization self-reported QOL questionnaire (physical health, psychological health, social relationships, and environmental factors) was used to assess the QOL. Student's t-test was used to compare the differences in a mean and change from baseline VO₂ max levels, whereas Wilcoxon signed-rank test was used to assess changes in QOL scores from baseline in the two groups.

Results:

There was a greater increase from baseline (P < 0.0001) in the mean VO₂ max with KSM-66 Ashwagandha (n = 24) compared to placebo (n = 25) at 8 weeks (4.91 and 1.42, respectively) and at 12 weeks (5.67 and 1.86 respectively). The QOL scores for all subdomains significantly improved to a greater extent in the Ashwagandha group at 12 weeks compared to placebo (P < 0.05).

Conclusion:

The findings suggest that Ashwagandha root extract enhances the cardiorespiratory endurance and improves QOL in healthy athletic adults.

Efficacy of Natural Compounds in Neurodegenerative Disorders

Neurodegenerative disorders represent clusters of serious diseases that results in progressive deterioration of normal structure and physiology of central nervous system. Pathophysiology of Alzheimer's, Parkinson's or other neurodegenerative disorders involves multifaceted permutation of genetic and environmental factors. Combinations of lifestyle modification linked with environmental factor jointly or alone represent the largest share of cases of these disorders. Etiology of such neuronal degeneration involves manifestation of toxic reaction in the form of functional anomalies leading to dysfunction of the ubiquitin-proteasome system, activated inflammatory cascade, compromised neuronal survival pathway, mitochondrial dysfunction and finally neuronal apoptosis/necrosis and cell death. Furthermore, evidences from various studies exhibited role of oxidative stress and compromised anti-oxidant defense system as one of the prime factors associated with activation of various signal transduction pathways that would ultimately lead to the formation of amyloid beta or alpha synuclein in the brain. Keeping in view of complex etiology and pathophysiology along with a miniscule of available treatment options associated with these neurodegenerative disorders, the role of natural agents and herbal extracts as therapeutic alternatives alone or in combination with synthetic drugs could not be ruled out. In the same context the present chapter has been aimed to investigate the role of selected natural plants like Withania somnifera, Bacopa monnieri, Curcuma longa, Centella asiatica, Ocimum sanctum, Nardostachys jatamansi and Emblica officinalis in various neurodegenerative disorders and explore their targets to ameliorate neurotoxicity in various experimental models. The rationale for selection of these plants was based on their strong anti-inflammatory and anti-oxidant potential and large body of evidence that suggest their efficacy in preclinical as well as in clinical studies. Active constituents if these herbals might play an important role in preserving the integrity of various neurotransmitters and their receptor in the brain influencing its functions at the molecular level.

Comparative transcriptome analysis of different chemotypes elucidates withanolide biosynthesis pathway from medicinal plant Withania somnifera

Withania somnifera is one of the most valuable medicinal plants synthesizing secondary metabolites known as withanolides. Despite pharmaceutical importance, limited information is available about the biosynthesis of withanolides. Chemo-profiling of leaf and root tissues of Withania suggest differences in the content and/or nature of withanolides in different chemotypes. To identify genes involved in chemotype and/or tissue-specific withanolide biosynthesis, we established transcriptomes of leaf and root tissues of distinct chemotypes. Genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis with their alternatively spliced forms and paralogous have been identified. Analysis suggests differential expression of large number genes among leaf and root tissues of different chemotypes. Study also identified differentially expressing transcripts encoding cytochrome P450s, glycosyltransferases, methyltransferases and transcription factors which might be involved in chemodiversity in Withania. Virus induced gene silencing of the sterol ∆7-reductase (WsDWF5) involved in the synthesis of 24-methylene cholesterol, withanolide backbone, suggests role of this enzyme in biosynthesis of withanolides. Information generated, in this study, provides a rich resource for functional analysis of withanolide-specific genes to elucidate chemotype- as well as tissue-specific withanolide biosynthesis. This genomic resource will also help in development of new tools for functional genomics and breeding in Withania.

AshwaMAX and Withaferin A inhibits gliomas in cellular and murine orthotopic models

Glioblastoma multiforme (GBM) is an aggressive, malignant cancer Johnson and O'Neill (J Neurooncol 107: 359-364, 2012). An extract from the winter cherry plant (Withania somnifera ), AshwaMAX, is concentrated (4.3 %) for Withaferin A; a steroidal lactone that inhibits cancer cells Vanden Berghe et al. (Cancer Epidemiol Biomark Prev 23: 1985-1996, 2014). We hypothesized that AshwaMAX could treat GBM and that bioluminescence imaging (BLI) could track oral therapy in orthotopic murine models of glioblastoma. Human parietal-cortical glioblastoma cells (GBM2, GBM39) were isolated from primary tumors while U87-MG was obtained commercially. GBM2 was transduced with lentiviral vectors that express Green Fluorescent Protein (GFP)/firefly luciferase fusion proteins. Mutational, expression and proliferative status of GBMs were studied. Intracranial xenografts of glioblastomas were grown in the right frontal regions of female, nude mice (n = 3-5 per experiment). Tumor growth was followed through BLI. Neurosphere cultures (U87-MG, GBM2 and GBM39) were inhibited by AshwaMAX at IC50 of 1.4, 0.19 and 0.22 µM equivalent respectively and by Withaferin A with IC50 of 0.31, 0.28 and 0.25 µM respectively. Oral gavage, every other day, of AshwaMAX (40 mg/kg per day) significantly reduced bioluminescence signal (n = 3 mice, p < 0.02, four parameter non-linear regression analysis) in preclinical models. After 30 days of treatment, bioluminescent signal increased suggesting onset of resistance. BLI signal for control, vehicle-treated mice increased and then plateaued. Bioluminescent imaging revealed diffuse growth of GBM2 xenografts. With AshwaMAX, GBM neurospheres collapsed at nanomolar concentrations. Oral treatment studies on murine models confirmed that AshwaMAX is effective against orthotopic GBM. AshwaMAX is thus a promising candidate for future clinical translation in patients with GBM.

Pharmacologic overview of Withania somnifera, the Indian Ginseng

Withania somnifera, also called 'Indian ginseng', is an important medicinal plant of the Indian subcontinent. It is widely used, singly or in combination, with other herbs against many ailments in Indian Systems of Medicine since time immemorial. Withania somnifera contains a spectrum of diverse phytochemicals enabling it to have a broad range of biological implications. In preclinical studies, it has shown anti-microbial, anti-inflammatory, anti-tumor, anti-stress, neuroprotective, cardioprotective, and anti-diabetic properties. Additionally, it has demonstrated the ability to reduce reactive oxygen species, modulate mitochondrial function, regulate apoptosis, and reduce inflammation and enhance endothelial function. In view of these pharmacologic properties, W. somnifera is a potential drug candidate to treat various clinical conditions, particularly related to the nervous system. In this review, we summarize the pharmacologic characteristics and discuss the mechanisms of action and potential therapeutic applications of the plant and its active constituents.

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.

A Decade of Molecular Understanding of Withanolide Biosynthesis and In vitro Studies in Withania somnifera (L.) Dunal: Prospects and Perspectives for Pathway Engineering

Withania somnifera, a multipurpose medicinal plant is a rich reservoir of pharmaceutically active triterpenoids that are steroidal lactones known as withanolides. Though the plant has been well-characterized in terms of phytochemical profiles as well as pharmaceutical activities, limited attempts have been made to decipher the biosynthetic route and identification of key regulatory genes involved in withanolide biosynthesis. This scenario limits biotechnological interventions for enhanced production of bioactive compounds. Nevertheless, recent emergent trends vis-à-vis, the exploration of genomic, transcriptomic, proteomic, metabolomics, and in vitro studies have opened new vistas regarding pathway engineering of withanolide production. During recent years, various strategic pathway genes have been characterized with significant amount of regulatory studies which allude toward development of molecular circuitries for production of key intermediates or end products in heterologous hosts. Another pivotal aspect covering redirection of metabolic flux for channelizing the precursor pool toward enhanced withanolide production has also been attained by deciphering decisive branch point(s) as robust targets for pathway modulation. With these perspectives, the current review provides a detailed overview of various studies undertaken by the authors and collated literature related to molecular and in vitro approaches employed in W. somnifera for understanding various molecular network interactions in entirety.

Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Improving Sexual Function in Women: A Pilot Study

Background. Many women experience sexual dysfunction where there are orgasm disorders and sexual difficulties. Ashwagandha (Withania somnifera) is a herb known to improve the body's physical and psychological condition. Objective. The purpose of the study was to determine the efficacy and safety of a high-concentration ashwagandha root extract (HCARE) supplementation for improving sexual function in healthy females. Methods. In this pilot study, 50 study subjects were randomized to either (i) HCARE-treated group or (ii) placebo- (starch-) treated group. The subjects consumed either HCARE or placebo capsules of 300mg twice daily for 8 weeks. Sexual function was assessed using two psychometric scales, the Female Sexual Function Index (FSFI) Questionnaire and the Female Sexual Distress Scale (FSDS), and by the number of total and successful sexual encounters. Results. The analysis indicates that treatment with HCARE leads to significantly higher improvement, relative to placebo, in the FSFI Total score (p < 0.001), FSFI domain score for “arousal” (p < 0.001), “lubrication” (p < 0.001), “orgasm” (p = 0.004), and “satisfaction” (p < 0.001), and also FSDS score (p < 0.001) and the number of successful sexual encounters (p < 0.001) at the end of the treatment. Conclusions. This study demonstrated that oral administration of HCARE may improve sexual function in healthy women. The present study is registered in the Clinical Trial Registry, Government of India, with a number CTRI/2015/07/006045.

Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera

We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO₃ were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms.

Nootropic potential of Ashwagandha leaves: Beyond traditional root extracts

Rapidly increasing aging population and environmental stressors are the two main global concerns of the modern society. These have brought in light rapidly increasing incidence of a variety of pathological conditions including brain tumors, neurodegenerative & neuropsychiatric disorders, and new challenges for their treatment. The overlapping symptoms, complex etiology and lack of full understanding of the brain structure and function to-date further complicate these tasks. On the other hand, several herbal reagents with a long history of their use have been asserted to possess neurodifferentiation, neuroregenerative and neuroprotective potentials, and hence been recommended as supplement to enhance and maintain brain health and function. Although they have been claimed to function by holistic approach resulting in maintaining body homeostasis and brain health, there are not enough laboratory studies in support to these and mechanism(s) of such beneficial activities remain largely undefined. One such herb is Ashwagandha, also called "Queen of Ayurveda" for its popular use in Indian traditional home medicine because of its extensive benefits including anticancer, anti-stress and remedial potential for aging and neurodegenerative pathologies. However, active principles and underlying mechanism(s) of action remain largely unknown. Here we provide a review on the effects of Ashwagandha extracts and active principles, and underlying molecular mechanism(s) for brain pathologies. We highlight our findings on the nootropic potential of Ashwagandha leaves. The effects of Ashwagandha leaf extracts are multidimensional ranging from differentiation of neuroblastoma and glioma cells, reversal of Alzheimer and Parkinson's pathologies, protection against environmental neurotoxins and enhancement of memory.

The Effect of a Complex Multi-modality Ayurvedic Treatment in a Case of Unknown Female Infertility

BACKGROUND

Treatment of female infertility has been growing globally in recent years. In spite of improvements in medical strategies and the improved outcomes for infertile couples, treatment attempts remain largely unsuccessful. A growing number of patients pursue complementary and alternative medicine treatment options like Ayurveda that offers a variety of inpatient and outpatient treatments for infertility.

CASE REPORT

A case of a 38 year-old woman with infertility of unknown origin is presented. She received 18 conventional fertility treatments in 5 different fertility centers and 3 different countries. After several complications, the patient quitted conventional treatment and admitted to an Ayurvedic outpatient clinic where she received a complex Ayurvedic treatment, which included botanicals, dietary and lifestyle advice, manual therapy, yoga, and spiritual elements. The patient then became pregnant and gave birth to a healthy boy in 2012.

CONCLUSIONS

Ayurveda may be a useful complementary option in the case of futile conventional treatment attempts in female infertility. Nevertheless, the evidence base for Ayurvedic interventions remains weak and requires well-designed clinical trials. This case raises some questions, such as whether the exposure to a large number of assisted reproduction procedures can lead to more health problems than health benefits. The Ayurvedic approach to fertility strives first to improve the health of the patient leading to a higher likelihood of pregnancy. As this is a case report, we are not able to exclude temporal factors stimulating the pregnancy. However, the chronology suggests that this approach might have been an important factor in the eventual pregnancy.

Hypoglycemic activity of withanolides and elicitated Withania somnifera

Withania somnifera, known in India as Asghawhanda, is used traditionally to treat many medical problems including diabetes and has demonstrated therapeutic activity in various animal models as well as in diabetic patients. While much of W. somnifera's therapeutic activity is attributed to withanolides, their role in the anti-diabetic activity of W. somnifera has not been adequately studied. In the present study, we evaluated the anti-diabetic activity of W. somnifera extract and purified withanolides, as well as the effect of various elicitors on this activity. W. somnifera leaf and root extracts increased glucose uptake in myotubes and adipocytes in a dose dependent manner, with the leaf extract more active than the root extract. Leaf but not root extract increased insulin secretion in basal pancreatic beta cells but not in stimulated cells. Six withanolides isolated from W. somnifera were tested for anti-diabetic activity based on glucose uptake in skeletal myotubes. Withaferin A was found to increase glucose uptake, with 10μM producing a 54% increase compared with control, suggesting that withaferin A is at least partially responsible for W. somnifera's anti-diabetic activity. Elicitors applied to the root growing solutions affected the physiological state of the plants, altering membrane leakage or osmotic potential. Methyl salicylate and chitosan increased withaferin A content by 75% and 69% respectively, and extracts from elicited plants increased glucose uptake to a higher extent than non-elicited plants, demonstrating a correlation between increased content of withaferin A and anti-diabetic activity.

Identification of anti-biofilm components in Withania somnifera and their effect on virulence of Streptococcus mutans biofilms

AIMS

The aim of this study was to identify components of the Withania somnifera that could show anti-virulence activity against Streptococcus mutans biofilms.

METHODS AND RESULTS

The anti-acidogenic activity of fractions separated from W. somnifera was compared, and then the most active anti-acidogenic fraction was chemically characterized using gas chromatography-mass spectroscopy. The effect of the identified components on the acidogenicity, aciduricity and extracellular polymeric substances (EPS) formation of S. mutans UA159 biofilms was evaluated. The change in accumulation and acidogenicity of S. mutans UA159 biofilms by periodic treatments (10 min per treatment) with the identified components was also investigated. Of the fractions, n-hexane fraction showed the strongest anti-acidogenic activity and was mainly composed of palmitic, linoleic and oleic acids. Of the identified components, linoleic and oleic acids strongly affected the acid production rate, F-ATPase activity and EPS formation of the biofilms. Periodic treatment with linoleic and oleic acids during biofilm formation also inhibited the biofilm accumulation and acid production rate of the biofilms without killing the biofilm bacteria.

CONCLUSIONS

These results suggest that linoleic and oleic acids may be effective agents for restraining virulence of S. mutans biofilms.

SIGNIFICANCE AND IMPACT OF THE STUDY

Linoleic and oleic acids may be promising agents for controlling virulence of cariogenic biofilms and subsequent dental caries formation.

Antiproliferation potential of withaferin A on human osteosarcoma cells via the inhibition of G2/M checkpoint proteins

Withaferin A (WA) is a well-known steroidal lactone of the medicinally important plant, Withania somnifera. This secondary metabolite has been noted for its anticancer effects against a number of human cancer cell lines. However, there are a limited number of studies investigating the growth inhibitory potential of WA against human osteosarcoma cells and the underlying molecular mechanisms. Thus, in the present study, the antiproliferative activities of WA, along with the underlying mechanisms of action, were investigated using flow cytometry for cell cycle distribution and western blot analysis for the assessment of various checkpoint proteins. In addition, the antiproliferative activity was evaluated using a sulforhodamine B assay, where MG-63 and U2OS human osteosarcoma cell lines were treated with different concentrations of WA. Furthermore, the mRNA expression levels of the checkpoint proteins in the WA-treated MG-63 and U2OS cells were examined. The results obtained corresponded with the western blot analysis results. Furthermore, WA was shown to significantly inhibit the proliferation of the two types of treated cell lines (MG-63 and U2OS). Flow cytometric analysis revealed that WA induced cell cycle arrest at the G2/M phase, which was associated with the inhibition of cyclin B1, cyclin A, Cdk2 and p-Cdc2 (Tyr15) expression and an increase in the levels of p-Chk1 (Ser345) and p-Chk2 (Thr68). In conclusion, the present study found that the antiproliferative potential of WA was associated with the induction of cell cycle arrest at the G2/M phase, which was a result of the attenuation of the expression levels of G2/M checkpoint proteins.

Brazilin isolated from Caesalpinia sappan L. inhibits rheumatoid arthritis activity in a type-II collagen induced arthritis mouse model

BACKGROUND

Caesalpinia sappan L. extracts exhibit great therapeutic potential, and have been shown to have analgesic and anti-inflammatory properties. This study aimed to understand the anti-rheumatoid activity of brazilin that was isolated from ethyl acetate extract of C. sappan L. The evaluations were conducted in mice with type-II collagen-induced arthritis (CIA).

METHODS

Brazilin was purified via preparative HPLC and identified by mass spectrometry and 1H/13C NMR analysis. DBA/1J mice were divided into four groups (n=10). Three groups of mice received intradermal injections of inducer bovine type-II collagen (BTIIC; 2 mg/ml in 0.05 ml acetic acid) and 0.1 ml of booster complete Freund's adjuvant (CFA). A second injection of BTIIC with booster incomplete Freund's adjuvant (ICFA) was given subsequently after 21 days. On 22nd day, purified brazilin (10 mg/kg body weight) or the disease-modifying anti-rheumatic drug methotrexate (3 mg/kg body weight) was administered intraperitoneally daily or every three days for 21 days, respectively to two groups of mice. At the 42nd day, mice sera were collected, and the levels of pro-inflammatory cytokines and stress enzyme markers in serum were measured using standard immunoassay methods. The microstructure and morphometric analyses of the bones were assessed using high-resolution microfocal computed tomography.

RESULTS

Brazilin isolated from C. sappan reduced the arthritis index score and the extent of acute inflammatory paw edema in CIA-mice. The bone mineral density was significantly (p<0.05) lower in only-CIA mice, and appeared to increase commensurate with methotrexate and brazilin administration. Brazilin prevented joint destruction, surface erosion, and enhanced bone formation as revealed by microstructural examinations. Brazilin markedly attenuated mouse CIA and reduced the serum levels of inflammatory cytokines including TNF-α, IL-1β, and IL-6.

CONCLUSIONS

Brazilin purified from C. sappan L. shows protective efficacy in CIA mouse, and may be useful to treat chronic inflammatory disorders including rheumatoid arthritis.

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.

Anticancer activities of Withania somnifera: Current research, formulations, and future perspectives

CONTEXT

Cancer, being a cause of death for major fraction of population worldwide, is one of the most studied diseases and is being investigated for the development of new technologies and more accurate therapies. Still the currently available therapies for cancer have many lacunae which affect the patient's health severely in the form of side effects. The natural drugs obtained from the medicinal plants provide a better alternative to fight against this devastating disease. Withania somnifera L. Dunal (Solanaceae), a well-known Ayurvedic medicinal plant, has been traditionally used to cure various ailments for centuries.

OBJECTIVES

Considering the immense potential of W. somnifera, this review provides a detail account of its vital phytoconstituents and summarizes the present status of the research carried out on its anticancerous activities, giving future directions.

METHODS

The sources of scientific literature were accessed from various electronic databases such as PubMed, Google Scholar, Science Direct, and library search.

RESULTS

Various parts of W. somnifera especially the roots with its unique contents have been proved effective against different kinds of cancers. The most active components withanolides and withaferins along with a few other metabolites including withanone (WN) and withanosides have been reported effective against different types of cancer cell lines.

CONCLUSION

This herb holds an important place among various anticancer medicinal plants. It is very essential to further screen and to investigate different formulations for anticancer therapy in vitro as well as in vivo in combination with established chemotherapy.

Effect of macronutrient deficiency on withanolides content in the roots of Withania somnifera and its correlationship with molybdenum content

CONTEXT

The content of withanolides in the roots of Withania somnifera (L.) Dunal (Solanaceae) is important for therapeutic application. Earlier studies have shown that the deficiency of macro- and micronutrients affects the growth of W. somnifera. Therefore, we examined the effect of these deficiencies on the withanolides content of the roots.

OBJECTIVE

To examine the effect of molybdenum accretion in nitrogen-, phosphorus-, calcium- and potassium-deficient soils on the accumulation of withanolides in the roots of W. somnifera. Different withanolides have different therapeutic applications hence major bioactive withanolides assume importance.

MATERIALS AND METHODS

Methanol extracts of the roots were subjected to HPTLC and individual withanolides were identified by comparing their Rf values with those of the authentic samples. Molybdenum was quantified by atomic absorption spectroscopy. Free radical scavenging activity was monitored by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay.

RESULTS

Molybdenum content in roots of nitrogen-, phosphorus-, calcium-, potassium-deficient, and control plants were 7.02 ± 2.1, 13.1 ± 1.6, 17.1 ± 0.9, 33.5 ± 3.3, and 33.9 ± 1.6 ppm, respectively. Levels of withaferine A increased with the increase in the Mo content in roots from 7.79 ± 2.2 mg/g to 12.57 ± 3.4 mg/g. Antioxidant activity of nitrogen-deficient plants was the lowest (24.7 ± 2.2%) compared to other groups.

DISCUSSION AND CONCLUSION

It was observed that nitrogen metabolism-dependent molybdenum uptake influences the withanolides accumulation in the roots.

Withanolide E sensitizes renal carcinoma cells to TRAIL-induced apoptosis by increasing cFLIP degradation

Withanolide E, a steroidal lactone from Physalis peruviana, was found to be highly active for sensitizing renal carcinoma cells and a number of other human cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Withanolide E, the most potent and least toxic of five TRAIL-sensitizing withanolides identified, enhanced death receptor-mediated apoptotic signaling by a rapid decline in the levels of cFLIP proteins. Other mechanisms by which TRAIL sensitizers have been reported to work: generation of reactive oxygen species (ROS), changes in pro-and antiapoptotic protein expression, death receptor upregulation, activation of intrinsic (mitochondrial) apoptotic pathways, ER stress, and proteasomal inhibition proved to be irrelevant to withanolide E activity. Loss of cFLIP proteins was not due to changes in expression, but rather destabilization and/or aggregation, suggesting impairment of chaperone proteins leading to degradation. Indeed, withanolide E treatment altered the stability of a number of HSP90 client proteins, but with greater apparent specificity than the well-known HSP90 inhibitor geldanamycin. As cFLIP has been reported to be an HSP90 client, this provides a potentially novel mechanism for sensitizing cells to TRAIL. Sensitization of human renal carcinoma cells to TRAIL-induced apoptosis by withanolide E and its lack of toxicity were confirmed in animal studies. Owing to its novel activity, withanolide E is a promising reagent for the analysis of mechanisms of TRAIL resistance, for understanding HSP90 function, and for further therapeutic development. In marked contrast to bortezomib, among the best currently available TRAIL sensitizers, withanolide E's more specific mechanism of action suggests minimal toxic side effects.

Transcriptome analysis reveals in vitro cultured Withania somnifera leaf and root tissues as a promising source for targeted withanolide biosynthesis

Background

The production of metabolites via in vitro culture is promoted by the availability of fully defined metabolic pathways. Withanolides, the major bioactive phytochemicals of Withania somnifera, have been well studied for their pharmacological activities. However, only a few attempts have been made to identify key candidate genes involved in withanolide biosynthesis. Understanding the steps involved in withanolide biosynthesis is essential for metabolic engineering of this plant to increase withanolide production.

Results

Transcriptome sequencing was performed on in vitro adventitious root and leaf tissues using the Illumina platform. We obtained a total of 177,156 assembled transcripts with an average unigene length of 1,033 bp. About 13% of the transcripts were unique to in vitro adventitious roots but no unique transcripts were observed in in vitro-grown leaves. A putative withanolide biosynthetic pathway was deduced by mapping the assembled transcripts to the KEGG database, and the expression of candidate withanolide biosynthesis genes -were validated by qRT PCR. The accumulation pattern of withaferin A and withanolide A varied according to the type of tissue and the culture period. Further, we demonstrated that in vitro leaf extracts exhibit anticancer activity against human gastric adenocarcinoma cell lines at sub G1 phase.

Conclusions

We report here a validated large-scale transcriptome data set and the potential biological activity of in vitro cultures of W. somnifera. This study provides important information to enhance tissue-specific expression and accumulation of secondary metabolites, paving the way for industrialization of in vitro cultures of W. somnifera.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1214-0) contains supplementary material, which is available to authorized users.

RNAi-mediated gene silencing of WsSGTL1 in W.somnifera affects growth and glycosylation pattern

Sterol glycosyltransferases (SGTs) belong to family 1 of glycosyltransferases (GTs) and are enzymes responsible for synthesis of sterol-glucosides (SGs) in many organisms. WsSGTL1 is a SGT of Withania somnifera that has been found associated with plasma membranes. However its biological function in W.somnifera is largely unknown. In the present study, we have demonstrated through RNAi silencing of WsSGTL1 gene that it performs glycosylation of withanolides and sterols resulting in glycowithanolides and glycosylated sterols respectively, and affects the growth and development of transgenic W.somnifera. For this, RNAi construct (pFGC1008-WsSGTL1) was made and genetic transformation was done by Agrobacterium tumefaciens. HPLC analysis depicts the reduction of withanoside V (the glycowithanolide of W.somnifera) and a large increase of withanolides (majorly withaferin A) content. Also, a significant decrease in level of glycosylated sterols has been observed. Hence, the obtained data provides an insight into the biological function of WsSGTL1 gene in W.somnifera.

Sterol partitioning by HMGR and DXR for routing intermediates toward withanolide biosynthesis

Withanolides biosynthesis in the plant Withania somnifera (L.) Dunal is hypothesized to be diverged from sterol pathway at the level of 24-methylene cholesterol. The conversion and translocation of intermediates for sterols and withanolides are yet to be characterized in this plant. To understand the influence of mevalonate (MVA) and 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways on sterols and withanolides biosynthesis in planta, we overexpressed the WsHMGR2 and WsDXR2 in tobacco, analyzed the effect of transient suppression through RNAi, inhibited MVA and MEP pathways and fed the leaf tissue with different sterols. Overexpression of WsHMGR2 increased cycloartenol, sitosterol, stigmasterol and campesterol compared to WsDXR2 transgene lines. Increase in cholesterol was, however, marginally higher in WsDXR2 transgenic lines. This was further validated through transient suppression analysis, and pathway inhibition where cholesterol reduction was found higher due to WsDXR2 suppression and all other sterols were affected predominantly by WsHMGR2 suppression in leaf. The transcript abundance and enzyme analysis data also correlate with sterol accumulation. Cholesterol feeding did not increase the withanolide content compared to cycloartenol, sitosterol, stigmasterol and campesterol. Hence, a preferential translocation of carbon from MVA and MEP pathways was found differentiating the sterols types. Overall results suggested that MVA pathway was predominant in contributing intermediates for withanolides synthesis mainly through the campesterol/stigmasterol route in planta.

Effect of Withania somnifera root extract on spontaneous estrogen receptor-negative mammary cancer in MMTV/Neu mice

The cancer-preventive activity of an extract of Withania somnifera (WS) roots was examined in female transgenic (MMTV/Neu) mice that received a diet containing the extract (750 mg/kg of diet) for 10 months. Mice in the treated group (n=35) had an average of 1.66 mammary carcinomas, and mice in the control group (n=33) had 2.48, showing a reduction of 33%. The average weights of the carcinomas were 2.36 g for mice in the treated group and 2.63 g for the controls, a difference of 10%. Labeling indices for Ki67 and proliferating cell nuclear antigen marker in mammary carcinomas of the treated group were 35% and 30% lower, respectively, than those of the corresponding control group. Expression of the chemokine was reduced by 50%. These results indicate that the root extract reduced the number of mammary carcinomas that developed and reduced the rate of cell division in the carcinomas.

Withania somnifera attenuates acid production, acid tolerance and extra-cellular polysaccharide formation of Streptococcus mutans biofilms

Withania somnifera (Ashwagandha) is a plant of the Solanaceae family. It has been widely used as a remedy for a variety of ailments in India and Nepal. The plant has also been used as a controlling agent for dental diseases. The aim of the present study was to evaluate the activity of the methanol extract of W. somnifera against the physiological ability of cariogenic biofilms and to identify the components of the extract. To determine the activity of the extract, assays for sucrose-dependent bacterial adherence, glycolytic acid production, acid tolerance, and extracellular polysaccharide formation were performed using Streptococcus mutans biofilms. The viability change of S. mutans biofilms cells was also determined. A phytochemical analysis of the extract was performed using TLC and LC/MS/MS. The extract showed inhibitory effects on sucrose-dependent bacterial adherence (≥ 100 μg/ml), glycolytic acid production (≥ 300 μg/ml), acid tolerance (≥ 300 μg/ml), and extracellular polysaccharide formation (≥ 300 μg/ml) of S. mutans biofilms. However, the extract did not alter the viability of S. mutans biofilms cells in all concentrations tested. Based on the phytochemical analysis, the activity of the extract may be related to the presence of alkaloids, anthrones, coumarines, anthraquinones, terpenoids, flavonoids, and steroid lactones (withanolide A, withaferin A, withanolide B, withanoside IV, and 12-deoxy withastramonolide). These data indicate that W. somnifera may be a potential agent for restraining the physiological ability of cariogenic biofilms.

Targeting Notch Signaling in Colorectal Cancer

The activation of Notch signaling is implicated in tumorigenesis in the colon due to the induction of pro-survival signaling in colonic epithelial cells. Chemoresistance is a major obstacle for treatment and for the complete eradication of colorectal cancer (CRC), hence, the inhibition of Notch is an attractive target for CRC and several groups are working to identify small molecules or monoclonal antibodies that inhibit Notch or its downstream events; however, toxicity profiles in normal cells and organs often impede the clinical translation of these molecules. Dietary agents have gained momentum for targeting several pro-survival signaling cascades, and recent studies demonstrated that agents that inhibit Notch signaling result in growth inhibition in preclinical models of CRC. In this review, we focus on the importance of Notch as a preventive and therapeutic target for colon cancer and on the effect of WA on this signaling pathway in the context of colon cancer.

In silico study of binding motifs in squalene synthase enzyme of secondary metabolic pathway of solanaceae [corrected]

Solanaceae is an important family with several plants of medicinal importance. These medicinal plants have distinctive pathways for secondary metabolite biosynthesis. In most of the plants, two important compounds, dimethylallyl diphosphate and isopentenyl diphosphate, synthesize isoprenoid or terpenoids. Squalene synthase (SQS) is a key enzyme of the biosynthesis of isoprenoid (farnesyl pyrophosphate (FPP) → squalene). Withania somnifera (ashwagandha), an important medicinal plant of family solanaceae produces withanolides. Withanolides are secondary metabolites synthesized through isoprenoid pathway. In this study, 13 SQS protein sequences from the plants of solanacae family and Arabidopsis thaliana were analyzed. The conserved domains in corresponding sequences were searched. The multiple sequence alignment of conserved domains revealed the important motifs and identified the residue substitution in each motif. Our result further indicated that residue substitution in motifs might not lead to functional variation, although it may affect the binding affinity of Mg(++), FPP and NAD(P)H. In addition, the homology modelling of SQS enzyme of W. somnifera was done for the prediction of three-dimensional structure. Molecular docking study of considered substrates with WsSQS was performed and the docked structure were analyzed further. The docked structures showed binding affinity for motif 2 of WsSQS. Our analysis revealed that 29 residues of motif 2 might be important for catalytic/functional activity of SQS enzyme of W. somnifera. This study may provide an understanding of metabolic pathways responsible for the production of secondary metabolites. The motifs may play a key role in regulating the pathway towards enhanced production of metabolites.

Plants and phytochemicals for Huntington's disease

Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive motor dysfunction, including chorea and dystonia, emotional disturbances, memory, and weight loss. The medium spiny neurons of striatum and cortex are mainly effected in HD. Various hypotheses, including molecular genetics, oxidative stress, excitotoxicity, metabolic dysfunction, and mitochondrial impairment have been proposed to explain the pathogenesis of neuronal dysfunction and cell death. Despite no treatment is available to fully stop the progression of the disease, there are treatments available to help control the chorea. The present review deals with brief pathophysiology of the disease, plants and phytochemicals that have shown beneficial effects against HD like symptoms. The literature for the current review was collected using various databases such as Science direct, Pubmed, Scopus, Sci-finder, Google Scholar, and Cochrane database with a defined search strategy.

Mammary cancer chemoprevention by withaferin A is accompanied by in vivo suppression of self-renewal of cancer stem cells

Current dogma favors elimination of therapy-resistant cancer stem cells for chemoprevention of breast cancer. We showed recently that mammary cancer development in a transgenic mouse model (mouse mammary tumor virus-neu; MMTV-neu) was inhibited significantly upon treatment with withaferin A (WA), a steroidal lactone derived from a medicinal plant. Herein, we demonstrate that the mammary cancer prevention by WA is accompanied by in vivo suppression of breast cancer stem cells (bCSC). In vitro mammosphere formation was dose-dependently inhibited by WA treatment in MCF-7 and SUM159 human breast cancer cells. Other markers of bCSC, including aldehyde dehydrogenase 1 (ALDH1) activity and CD44(high)/CD24(low)/epithelial-specific antigen-positive (ESA+) fraction, were also decreased significantly in the presence of plasma achievable doses of WA. However, WA exposure resulted in cell line-specific changes in Oct4, SOX-2, and Nanog mRNA expression. WA administration to MMTV-neu mice (0.1 mg/mouse, 3 times/week for 28 weeks) resulted in inhibition of mammosphere number and ALDH1 activity in vivo. Mechanistic studies revealed that although urokinase-type plasminogen activator receptor overexpression conferred partial protection against bCSC inhibition by WA, Notch4 was largely dispensable for this response. WA treatment also resulted in sustained (MCF-7) or transient (SUM159) downregulation of Bmi-1 (B-cell-specific Moloney murine leukemia virus insertion region-1) protein. Ectopic expression of Bmi-1 conferred partial but significant protection against ALDH1 activity inhibition by WA. Interestingly, WA treatment caused induction of Kruppel-like factor 4 (KLF4) and its knockdown augmented bCSC inhibition by WA. In conclusion, this study shows in vivo effectiveness of WA against bCSC.

Cloning and functional characterization of three branch point oxidosqualene cyclases from Withania somnifera (L.) dunal

Oxidosqualene cyclases (OSCs) positioned at a key metabolic subdividing junction execute indispensable enzymatic cyclization of 2,3-oxidosqualene for varied triterpenoid biosynthesis. Such branch points present favorable gene targets for redirecting metabolic flux toward specific secondary metabolites. However, detailed information regarding the candidate OSCs covering different branches and their regulation is necessary for the desired genetic manipulation. The aim of the present study, therefore, was to characterize members of OSC superfamily from Withania somnifera (Ws), a medicinal plant of immense repute known to synthesize a large array of biologically active steroidal lactone triterpenoids called withanolides. Three full-length OSC cDNAs, β-amyrin synthase (WsOSC/BS), lupeol synthase (WsOSC/LS), and cycloartenol synthase (WsOSC/CS), having open reading frames of 2289, 2268, and 2277 bp, were isolated. Heterologous expression in Schizosaccharomyces pombe, LC-MS analyses, and kinetic studies confirmed their monofunctionality. The three WsOSCs were found to be spatially regulated at transcriptional level with WsOSC/CS being maximally expressed in leaf tissue. Promoter analysis of three WsOSCs genes resulted in identification of distinct cis-regulatory elements. Further, transcript profiling under methyl jasmonate, gibberellic acid, and yeast extract elicitations displayed differential transcriptional regulation of each of the OSCs. Changes were also observed in mRNA levels under elicitations and further substantiated with protein expression levels by Western blotting. Negative regulation by yeast extract resulted in significant increase in withanolide content. Empirical evidence suggests that repression of competitive branch OSCs like WsOSC/BS and WsOSC/LS possibly leads to diversion of substrate pool toward WsOSC/CS for increased withanolide production.

Mechanistic elucidation of the antitumor properties of withaferin a in breast cancer

Withaferin A (WFA) is a steroidal lactone with antitumor effects manifested at multiple levels that are mechanistically obscure. Using a phospho-kinase screening array, we discovered that WFA activated phosphorylation of the S6 kinase RSK (ribosomal S6 kinase) in breast cancer cells. Pursuing this observation, we defined activation of extracellular signal-regulated kinase (ERK)-RSK and ETS-like transcription factor 1 (Elk1)-CHOP (C-EBP homologous protein) kinase pathways in upregulating transcription of the death receptor 5 (DR5). Through this route, WFA acted as an effective DR5 activator capable of potentiating the biologic effects of celecoxib, etoposide, and TRAIL. Accordingly, WFA treatment inhibited breast tumor formation in xenograft and mouse mammary tumor virus (MMTV)-neu mouse models in a manner associated with activation of the ERK/RSK axis, DR5 upregulation, and elevated nuclear accumulation of Elk1 and CHOP. Together, our results offer mechanistic insight into how WFA inhibits breast tumor growth.

Evaluation of anti-inflammatory effect of Withania somnifera root on collagen-induced arthritis in rats

CONTEXT

Withania somnifera (Linn.) Dunal (Solanaceae) has long been used as an herb in Ayurvedic and indigenous medicine and has received intense attention in recent years for its chemopreventive properties.

OBJECTIVE

The present study focuses on the effect of W. somnifera root powder on the behavioral and radiological changes in collagen-induced arthritic rats.

MATERIALS AND METHODS

The rats were randomly divided into five groups: normal control, arthritic control, arthritic rats treated with W. somnifera root powder (at dose levels 600 and 800 mg kg⁻¹) and arthritic rats treated with methotrexate (at dose level 0.3 mg kg⁻¹). The treatment with W. somnifera (daily) and methotrexate (weekly) was initiated from the 20th day post collagen immunization and continued up until the 45th day. Arthritis was assessed macroscopically by measuring paw thickness, ankle size and body weight. Arthritic pain was assessed by toe-spread and total print length of the affected paw. Functional recovery due to the oral treatment of W. somnifera and methotrexate was assessed by sciatic functional index and rota rod activity.

RESULTS

Administration of W. somnifera root powder (600 mg kg⁻¹) to the arthritic rats significantly decreased the severity of arthritis by effectively suppressing the symptoms of arthritis and improving the functional recovery of motor activity and radiological score.

DISCUSSION AND CONCLUSION

W. somnifera root has a protective effect against collagen-induced arthritis (CIA) in rats. The results suggest that W. somnifera root powder acts as an anti-inflammatory and antioxidant agent in decreasing the arthritic effects in collagen-induced arthritic rats.

Epoxide group relationship with cytotoxicity in withanolide derivatives from Withania somnifera

Withania somnifera is one of the highly reputed medicinal plants of India. Its steroidal constituents exist in the form of two major substitution patterns, viz. withaferin A (1) and withanone (5). Withaferin A with oxidation at carbons 4, 5, and 6 is considered as an active type, especially as anticancer, whereas the withanones with oxidation at carbons 5, 6, and 7 rarely show any activity. We prepared a series of derivatives with modifications at carbons 5, 6, and 7 in ring B of these withanolides to study the role of the epoxide group towards the cytotoxic property of these bioactive steroids. We have converted withanolides into the respective thiiranes, amino alcohols and alcohols by selective reactions at the epoxide ring and were evaluated for in vitro anticancer activity against four cancer cell lines to study the structure activity relationships. The transformations of the epoxide group in withanolides of the withaferin A type showed moderate reduction in their cytotoxicity whereas the almost inactive withanones have shown some improvements in their alcohol derivatives.

Clinical Evaluation of the Spermatogenic Activity of the Root Extract of Ashwagandha (Withania somnifera) in Oligospermic Males: A Pilot Study

Ashwagandha (Withania somnifera) has been described in traditional Indian Ayurvedic medicine as an aphrodisiac that can be used to treat male sexual dysfunction and infertility. This pilot study was conducted to evaluate the spermatogenic activity of Ashwagandha root extract in oligospermic patients. Forty-six male patients with oligospermia (sperm count < 20 million/mL semen) were enrolled and randomized either to treatment (n = 21) with a full-spectrum root extract of Ashwagandha (675 mg/d in three doses for 90 days) or to placebo (n = 25) in the same protocol. Semen parameters and serum hormone levels were estimated at the end of 90-day treatment. There was a 167% increase in sperm count (9.59 ± 4.37 × 10⁶/mL to 25.61 ± 8.6 × 10⁶/mL; P < 0.0001), 53% increase in semen volume (1.74 ± 0.58 mL to 2.76 ± 0.60 mL; P < 0.0001), and 57% increase in sperm motility (18.62 ± 6.11% to 29.19 ± 6.31%; P < 0.0001) on day 90 from baseline. The improvement in these parameters was minimal in the placebo-treated group. Furthermore, a significantly greater improvement and regulation were observed in serum hormone levels with the Ashwagandha treatment as compared to the placebo. The present study adds to the evidence on the therapeutic value of Ashwagandha (Withania somnifera), as attributed in Ayurveda for the treatment of oligospermia leading to infertility.

Chemical and pharmacological standardization of Ashwagandhadi lehyam: an ayurvedic formulation

Standardization is an important measurement for ensuring the quality control of herbal drugs. It has become essential to develop reliable, specific and sensitive quality control methods. One of the prime ingredients of Ashwagandhadi lehyam is Withania somnifera L. Dunal (Solanaceae) (ashwagandha). In the present study, Ashwagandhadi lehyam was formulated and the quality assessment of the formulation was based on phytochemical screening and physico-chemical evaluation. Ashwagandhadi lehyam was formulated according to a working formula and subjected to phytochemical screening by FTIR analysis and HPTLC fingerprinting, heavy metal determination by AAS, determination of alcohol content, tested for Escherichia coli, Staphylococcus aureus, aerobic bacteria, yeasts and mould, oral toxicity studies and anti-epileptic activity by MES method. The physico-chemical studies showed total ash content as 6.45%, extractive values and some trace elements such as lead, mercury, cadmium and arsenic with 3.2, 0.05, 0.18 and 0.48 ppm, respectively. FTIR and HPTLC studies revealed the presence of functional groups of withanolides in Ashwagandhadi lehyam, resulting in its chemical standardization. The formulation exhibited less epileptic seizures in various phases when compared with that of standard phenytoin and found to possess better anti-inflammatory activity, thus making it biologically standardized. The physico-chemical and pharmacological analysis to standardize Ashwagandhadi lehyam confirmed its use as a safe anti-inflammatory agent and for various seizure disorders.

Water extract of Ashwagandha leaves has anticancer activity: identification of an active component and its mechanism of action

Background

Cancer is a leading cause of death accounting for 15-20% of global mortality. Although advancements in diagnostic and therapeutic technologies have improved cancer survival statistics, 75% of the world population live in underdeveloped regions and have poor access to the advanced medical remedies. Natural therapies hence become an alternative choice of treatment. Ashwagandha, a tropical herb used in Indian Ayurvedic medicine, has a long history of its health promoting and therapeutic effects. In the present study, we have investigated an anticancer activity in the water extract of Ashwagandha leaves (ASH-WEX).

Methodology/Principal Findings

Anticancer activity in the water extract of Ashwagandha leaves (ASH-WEX) was detected by invitro and invivo assays. Bioactivity-based size fractionation and NMR analysis were performed to identify the active anticancer component(s). Mechanism of anticancer activity in the extract and its purified component was investigated by biochemical assays. We report that the ASH-WEX is cytotoxic to cancer cells selectively, and causes tumor suppression invivo. Its active anticancer component was identified as triethylene glycol (TEG). Molecular analysis revealed activation of tumor suppressor proteins p53 and pRB by ASH-WEX and TEG in cancer cells. In contrast to the hypophosphorylation of pRB, decrease in cyclin B1 and increase in cyclin D1 in ASH-WEX and TEG-treated cancer cells (undergoing growth arrest), normal cells showed increase in pRB phosphorylation and cyclin B1, and decrease in cyclin D1 (signifying their cell cycle progression). We also found that the MMP-3 and MMP-9 that regulate metastasis were down regulated in ASH-WEX and TEG-treated cancer cells; normal cells remained unaffected.

Conclusion

We provide the first molecular evidence that the ASH-WEX and TEG have selective cancer cell growth arrest activity and hence may offer natural and economic resources for anticancer medicine.

Bioengineering of plant (tri)terpenoids: from metabolic engineering of plants to synthetic biology in vivo and in vitro

Terpenoids constitute a large and diverse class of natural products that serve many functions in nature. Most of the tens of thousands of the discovered terpenoids are synthesized by plants, where they function as primary metabolites involved in growth and development, or as secondary metabolites that optimize the interaction between the plant and its environment. Several plant terpenoids are economically important molecules that serve many applications as pharmaceuticals, pesticides, etc. Major challenges for the commercialization of plant-derived terpenoids include their low production levels in planta and the continuous demand of industry for novel molecules with new or superior biological activities. Here, we highlight several synthetic biology methods to enhance and diversify the production of plant terpenoids, with a foresight towards triterpenoid engineering, the least engineered class of bioactive terpenoids. Increased or cheaper production of valuable triterpenoids may be obtained by 'classic' metabolic engineering of plants or by heterologous production of the compounds in other plants or microbes. Novel triterpenoid structures can be generated through combinatorial biosynthesis or directed enzyme evolution approaches. In its ultimate form, synthetic biology may lead to the production of large amounts of plant triterpenoids in in vitro systems or custom-designed artificial biological systems.

Tropine forming tropinone reductase gene from Withania somnifera (Ashwagandha): biochemical characteristics of the recombinant enzyme and novel physiological overtones of tissue-wide gene expression patterns

Withania somnifera is one of the most reputed medicinal plants of Indian systems of medicine synthesizing diverse types of secondary metabolites such as withanolides, alkaloids, withanamides etc. Present study comprises cloning and E. coli over-expression of a tropinone reductase gene (WsTR-I) from W. somnifera, and elucidation of biochemical characteristics and physiological role of tropinone reductase enzyme in tropane alkaloid biosynthesis in aerial tissues of the plant. The recombinant enzyme was demonstrated to catalyze NADPH-dependent tropinone to tropine conversion step in tropane metabolism, through TLC, GC and GC-MS-MS analyses of the reaction product. The functionally active homodimeric ∼60 kDa enzyme catalyzed the reaction in reversible manner at optimum pH 6.7. Catalytic kinetics of the enzyme favoured its forward reaction (tropine formation). Comparative 3-D models of landscape of the enzyme active site contours and tropinone binding site were also developed. Tissue-wide and ontogenic stage-wise assessment of WsTR-I transcript levels revealed constitutive expression of the gene with relatively lower abundance in berries and young leaves. The tissue profiles of WsTR-I expression matched those of tropine levels. The data suggest that, in W. somnifera, aerial tissues as well possess tropane alkaloid biosynthetic competence. In vivo feeding of U-[¹⁴C]-sucrose to orphan shoot (twigs) and [¹⁴C]-chasing revealed substantial radiolabel incorporation in tropinone and tropine, confirming the de novo synthesizing ability of the aerial tissues. This inherent independent ability heralds a conceptual novelty in the backdrop of classical view that these tissues acquire the alkaloids through transportation from roots rather than synthesis. The TR-I gene expression was found to be up-regulated on exposure to signal molecules (methyl jasmonate and salicylic acid) and on mechanical injury. The enzyme's catalytic and structural properties as well as gene expression profiles are discussed with respect to their physiological overtones.

Molecular targets and mechanisms of cancer prevention and treatment by withaferin a, a naturally occurring steroidal lactone

The plants used in Ayurvedic medicine, which has been practiced in India for thousands of years for the treatment of a variety of disorders, are rich in chemicals potentially useful for prevention and treatment of cancer. Withania somnifera (commonly known as Ashwagandha in Ayurvedic medicine) is one such medicinal plant whose anticancer value was realized over four decades ago after isolation of a crystalline steroidal compound (withaferin A) from the leaves of this shrub. The root and leaf extracts of W. somnifera are shown to confer protection against chemically-induced cancers in experimental rodents, and retard tumor xenograft growth in athymic mice. Anticancer effect of W. somnifera is generally attributable to steroidal lactones collectively referred to as withanolides. Withaferin A (WA) appears most active against cancer among structurally divergent withanolides isolated from the root or leaf of W. somnifera. Cancer-protective role for WA has now been established using chemically-induced and oncogene-driven rodent cancer models. This review summarizes the key in vivo preclinical studies demonstrating anticancer effects of WA. Molecular targets and mechanisms likely contributing to the anticancer effects of WA are also discussed. Finally, challenges in clinical development of WA for the prevention and treatment of cancer are highlighted.

De novo assembly, functional annotation and comparative analysis of Withania somnifera leaf and root transcriptomes to identify putative genes involved in the withanolides biosynthesis

Withania somnifera is one of the most valuable medicinal plants used in Ayurvedic and other indigenous medicine systems due to bioactive molecules known as withanolides. As genomic information regarding this plant is very limited, little information is available about biosynthesis of withanolides. To facilitate the basic understanding about the withanolide biosynthesis pathways, we performed transcriptome sequencing for Withania leaf (101L) and root (101R) which specifically synthesize withaferin A and withanolide A, respectively. Pyrosequencing yielded 8,34,068 and 7,21,755 reads which got assembled into 89,548 and 1,14,814 unique sequences from 101L and 101R, respectively. A total of 47,885 (101L) and 54,123 (101R) could be annotated using TAIR10, NR, tomato and potato databases. Gene Ontology and KEGG analyses provided a detailed view of all the enzymes involved in withanolide backbone synthesis. Our analysis identified members of cytochrome P450, glycosyltransferase and methyltransferase gene families with unique presence or differential expression in leaf and root and might be involved in synthesis of tissue-specific withanolides. We also detected simple sequence repeats (SSRs) in transcriptome data for use in future genetic studies. Comprehensive sequence resource developed for Withania, in this study, will help to elucidate biosynthetic pathway for tissue-specific synthesis of secondary plant products in non-model plant organisms as well as will be helpful in developing strategies for enhanced biosynthesis of withanolides through biotechnological approaches.

Overexpression of WsSGTL1 gene of Withania somnifera enhances salt tolerance, heat tolerance and cold acclimation ability in transgenic Arabidopsis plants

Background

Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress.

Methodology

The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5.

Results

The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana.

Conclusions

Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress responsive elements. The 3D structure showed functional similarity with sterol glycosyltransferases.