Emerging role of Centella asiatica in improving age-related neurological antioxidant status

Centella asiatica (L.) Urb. and Hydrocotyle umbellata L. identification and quality assessment: A methodology comparison

INTRODUCTION

Centella is an important genus in the Apiaceae family. It includes Centella asiatica, which has significant edible and medicinal values. However, this species is easily confused due to its similar morphological traits to Hydrocotyle umbellata, hindering its utilization in the consumer and pharmacological industries.

OBJECTIVE

The study aims to differentiate these two closely related plant species using reliable methods of confirming the authenticity of natural herbal medicines.

METHODS

Our work mainly focuses on the basic morphological characteristics, chemical markers, genetic fingerprints, and their biological responses.

RESULTS

The plants can be clearly differentiated using their leaf shapes, stipules, petioles, inflorescences, and fruit structures. Although the phytochemical compositions of the C. asiatica extract were similar to that of H. umbellata which included flavonoids, tannins, and saponins important to the plant's ability to reduce inflammation and promote healing of wounds, the H. umbellata extract showed significantly higher toxicity than that of C. asiatica. High-performance liquid chromatography analysis was used to identify chemical fingerprints. The result revealed that C. asiatica had major triterpene glycoside constituents including asiaticoside, asiatic acid, madecassoside, and madecassic acid, which have a wide range of medicinal values. In contrast, triterpenoid saponins were not identified in H. umbellata. Furthermore, using SCoT1-6 primers was possible to effectively and sufficiently created a dendrogram which successfully identified the closeness of the plants and confirmed the differences between the two plant species.

CONCLUSION

Therefore, differentiation can be achieved through the combination of morphometrics, molecular bioactivity, and chemical analysis.

Centella asiatica improves memory and executive function in middle-aged rats by controlling oxidative stress and cholinergic transmission

ETHNOPHARMACOLOGICAL RELEVANCE

Centella asiatica (L.) Urban, is a medicinal herb with rich history of traditional use in Indian subcontinent. This herb has been valued for its diverse range of medicinal properties including memory booster, and also as a folk treatment for skin diseases, wound healing and mild diuretic.

AIM OF STUDY

Aging is a gradual and continuous process of natural decay in the biological systems, including the brain. This work aims to evaluate the effectiveness of ethanolic extract of Centella asiatica (CAE) on age-associated cognitive impairments in rats, as well as the underlying mechanism.

MATERIAL AND METHODS

Rats were allocated into five distinct groups of 5 animals each: Young rats (3 months old rats), middle-aged (m-aged) rats (13-14 months old), and the remaining three groups were comprised of m-aged rats treated with different concentrations of CAE, viz., 150, 300, and 450 mg/kg b. w., orally for 42 days. Y-maze, open field, novel object recognition, and elevated plus maze tests were used to assess animal behavior. The malondialdehyde (MDA), superoxide dismutase (SOD), and acetylcholinesterase (AChE) assays; and H&E staining were done in the rat brain to assess the biochemical and structural changes. CAE was also subjected to HPLC analysis, in vitro antioxidant and anti-cholinergic activity. The active compounds of CAE were docked with AChE and BuChE in molecular docking study.

RESULTS

The results showed that CAE treatment improves behavioral performance; attenuates the age-associated increase in MDA content, SOD, and AChE activity; and reduces neuronal loss. In vitro study showed that CAE has concentration-dependent antioxidant and anti-AChE activity. Furthermore, the presence of Asiatic acid and Madecassic acid in CAE and their good binding with cholinergic enzymes (in silico) also suggest the anticholinergic effect of CAE.

CONCLUSION

The findings of the current study show that the anticholinergic and antioxidant effects of CAE are attributable to the presence of Asiatic acid and Madecassic acid, which not only provide neuroprotection against age-associated cognitive decline but also reverse it.

Nootropic Herbs, Shrubs, and Trees as Potential Cognitive Enhancers

Plant-based nootropics are a diverse group of natural drugs that can improve cognitive abilities through various physiological mechanisms, especially in cases where these functions are weakened or impaired. In many cases, the nootropics enhance erythrocyte plasticity and inhibit aggregation, which improves the blood's rheological properties and increases its flow to the brain. Many of these formulations possess antioxidant activity that protects brain tissue from neurotoxicity and improves the brain's oxygen supply. They can induce the synthesis of neuronal proteins, nucleic acids, and phospholipids for constructing and repairing neurohormonal membranes. These natural compounds can potentially be present in a great variety of herbs, shrubs, and even some trees and vines. The plant species reviewed here were selected based on the availability of verifiable experimental data and clinical trials investigating potential nootropic effects. Original research articles, relevant animal studies, meta-analyses, systematic reviews, and clinical trials were included in this review. Selected representatives of this heterogeneous group included Bacopa monnieri (L.) Wettst., Centella asiatica (L.) Urban, Eleutherococcus senticosus (Rupr. & Maxim.) Maxim., Ginkgo biloba L., Lepidium meyenii Walp., Panax ginseng C.A. Meyer, Paullinia cupana Kunth, Rhodiola rosea L., Schisandra chinensis (Turcz.) Baill., and Withania somnifera (L.) Dunal. The species are depicted and described, together with their active components and nootropic effects, and evidence of their efficacy is presented. The study provides brief descriptions of the representative species, their occurrence, history, and the chemical composition of the principle medicinal compounds, with uses, indications, experimental treatments, dosages, possible side effects, and contraindications. Most plant nootropics must be taken at optimal doses for extended periods before measurable improvement occurs, but they are generally very well tolerated. Their psychoactive properties are not produced by a single molecule but by a synergistic combination of several compounds. The available data suggest that including extracts from these plants in medicinal products to treat cognitive disorders can have substantial potential therapeutic benefits.

Centella asiatica (L.) Urb. Extract ameliorates branched-chain amino acid (BCAA) metabolism in acute reserpine-induced stress zebrafish model via 1H Nuclear Magnetic Resonance (NMR)-based metabolomics approach

Depression is a common mental disorder that can adversely affect psychosocial function and quality of life. However, the exact aetiology and pathogenesis of depression are still unclear. Stress plays a major role in the pathogenesis of depression. The use of currently prescribed antidepressants has many side effects. Centella asiatica (C. asiatica) has shown promising antidepressant activity in rodent models. Here, we developed a reserpine-induced zebrafish stress-like model and performed behavioural analysis, cortisol measurement and ¹H-Nuclear Magnetic Resonance (¹H NMR) spectroscopy-based metabolomics analysis to test the anti-stress activity of ethanolic extract of C. asiatica (RECA). A significant increase in total distance travelled (F_(8,8) = 8.905, p = 0.0054) and a reduction in freezing duration (F_{(9, 9)} = 10.38, p = 0.0018) were found in the open field test (OFT). Asiaticoside, one of tested C.asiatica's triterpenoid gives a significant increase in contact duration (F_(5,5) = 142.3, (p = 0.0330) at 2.5 mg/kg). Eight biomarkers were found, i.e. ß-hydroxyisovaleric acid, leucine, threonine, scylloinositol, lactate, betaine, valine, choline and l-fucose, to be responsible for the class separation between stress and RECA-treated groups. Metabolic pathway alteration in zebrafish brain upon treatment with RECA was identified as valine, leucine and isoleucine biosynthesis, while alanine, aspartate, glutamate and glycerophospholipid metabolism was involved after fluoxetine treatment.

Herbal Therapeutics for Alzheimer's Disease: Ancient Indian Medicine System from the Modern Viewpoint

Alzheimer's is a chronic neurodegenerative disease where amyloid-beta (Aβ) plaques and neurofibrillary tangles are formed inside the brain. It is also characterized by progressive memory loss, depression, neuroinflammation, and derangement of other neurotransmitters. Due to its complex etiopathology, current drugs have failed to completely cure the disease. Natural compounds have been investigated as an alternative therapy for their ability to treat Alzheimer's disease (AD). Traditional herbs and formulations which are used in the Indian ayurvedic system are rich sources of antioxidant, anti-amyloidogenic, neuroprotective, and anti-inflammatory compounds. They promote quality of life by improving cognitive memory and rejuvenating brain functioning through neurogenesis. A rich knowledge base of traditional herbal plants (Turmeric, Gingko, Ashwagandha, Shankhpushpi, Giloy, Gotu kola, Garlic, Tulsi, Ginger, and Cinnamon) combined with modern science could suggest new functional leads for Alzheimer's drug discovery. In this article Ayurveda, the ancient Indian herbal medicine system based on multiple clinical and experimental, evidence have been reviewed for treating AD and improving brain functioning. This article presents a modern perspective on the herbs available in the ancient Indian medicine system as well as their possible mechanisms of action for AD treatment. The main objective of this research is to provide a systematic review of herbal drugs that are easily accessible and effective for the treatment of AD.

Medicinal plants and their secondary metabolites in alleviating knee osteoarthritis: A systematic review

BACKGROUND

With the increasing ages of the general population, the incidence of knee osteoarthritis (KOA) is also rising, and KOA has become a major health problem worldwide. Recently, medicinal plants and their secondary metabolites have gained interest due to their activity in treating KOA. In this paper, a comprehensive systematic review of the literature was performed concerning the effects of medicinal plant extracts and natural compounds against KOA in recent years. The related molecular pathways of natural compounds against KOA were summarized, and the possible crosstalk among components in chondrocytes was discussed to propose possible solutions for the current situation of treating KOA.

PURPOSE

This review focused on the molecular mechanisms by which medicinal plants and their secondary metabolites act against KOA.

METHODS

Literature searches were performed in the PUBMED, Embase, Science Direct, and Web of Science databases for a 10-year period from 2011 to 2022 with the search terms "medicinal plants," "bioactive compounds," "natural products," "phytochemical," "knee osteoarthritis," "knee joint osteoarthritis," "knee osteoarthritis," "osteoarthritis of the knee," and "osteoarthritis of knee joint."

RESULTS

According to the results, substantial plant extracts and secondary metabolites show a positive effect in fighting KOA. Plant extracts and their secondary metabolites can affect the diagnostic and prognostic biomarkers of KOA. Natural products inhibit the expression of MMP1, MMP3, MMP19, syndecan IV, ADAMTS-4, ADAMTS-5, iNOS, COX-2, collagenases, IL-6, IL-1β, and TNF-α in vitro and in vivo and . Cytokines also upregulate the expression of collagen II and aggrecan. The main signaling pathways affected by the extracts and isolated compounds include AMPK, SIRT, NLRP3, MAPKs, PI3K/AKT, mTOR, NF-κB, WNT/β-catenin, JAK/STAT3, and NRF2, as well as the cell death modes apoptosis, autophagy, pyroptosis, and ferroptosis.

CONCLUSION

The role of secondary metabolites in different signaling pathways supplies a better understanding of their potential to develop further curative options for KOA.

Efficacy of a vegetal mixture composed of Zingiber officinale, Echinacea purpurea, and Centella asiatica in a mouse model of neuroinflammation: In vivo and ex vivo analysis

Experimental evidence suggests that neuroinflammation is a key pathological event of many diseases affecting the nervous system. It has been well recognized that these devastating illnesses (e.g., Alzheimer’s, Parkinson’s, depression, and chronic pain) are multifactorial, involving many pathogenic mechanisms, reason why pharmacological treatments are unsatisfactory. The purpose of this study was to evaluate the efficacy of a vegetal mixture capable of offering a multiple approach required to manage the multifactoriality of neuroinflammation. A mixture composed of Zingiber officinale (150 mg kg⁻¹), Echinacea purpurea (20 mg kg⁻¹), and Centella asiatica (200 mg kg⁻¹) was tested in a mouse model of systemic neuroinflammation induced by lipopolysaccharide (LPS, 1 mg kg⁻¹). Repeated treatment with the vegetal mixture was able to completely counteract thermal and mechanical allodynia as reported by the Cold plate and von Frey tests, respectively, and to reduce the motor impairments as demonstrated by the Rota rod test. Moreover, the mixture was capable of neutralizing the memory loss in the Passive avoidance test and reducing depressive-like behavior in the Porsolt test, while no efficacy was shown in decreasing anhedonia as demonstrated by the Sucrose preference test. Finally, LPS stimulation caused a significant increase in the activation of glial cells, of the central complement proteins and of inflammatory cytokines in selected regions of the central nervous system (CNS), which were rebalanced in animals treated with the vegetal mixture. In conclusion, the vegetal mixture tested thwarted the plethora of symptoms evoked by LPS, thus being a potential candidate for future investigations in the context of neuroinflammation.

Inhibition of hypertrophic scar formation with oral asiaticoside treatment in a rabbit ear scar model

Hypertrophic scar (HS) is a fibrotic skin disease characterised by over‐productive collagen and excessive inflammatory reaction, which can be functionally and cosmetically problematic. A scar‐prone constitute will accelerate HS formation and functional disorder, which deserves systemic therapy with oral medicine. To examine the oral therapeutic effectiveness on HS with convincing evidence of gross view and histological improvement, a rabbit ear HS model was employed with oral administration of asiaticoside (AS) at the doses of 12 and 24 mg kg⁻¹ d⁻¹ daily for 60 consecutive days. Gross observation and histological findings showed that oral AS treatment could significantly inhibit HS formation in a dose dependent manner. Semi‐quantification of scar elevation index at days 7, 15, 30, and 60, and quantitative polymerase chain reaction at days 30 and 60 also provided the evidences of reduced scar thickness and inhibited fibrotic gene expressions of collagens I, III, TGF‐β1, interleukins 1β, 6 and 8, and enhanced gene expression of SMAD 7 and PPAR‐γ with a dose‐dependent manner. These results indicated that AS is likely to serve as a systemic therapeutic agent of HS treatment for those who may have scar‐prone constitute via anti‐inflammation, inhibiting fibrotic process, and enhancing matrix degradation.

Ceftriaxone improves hepatorenal damages in mice subjected to D-galactose-induced aging

Ceftriaxone (CTX) is a third-generation cephalosporin antibiotic that has broad-spectrum antimicrobial activity. This agent also has anti-inflammatory and antioxidant characteristics. In the current study, the effects of CTX against hepatorenal damages in a D-galactose (DGL) induced aging model were investigated. We used twenty-eight male mice which equally and randomly were separated into four groups as follows: Control, DGL group (treated with 500 mg/kg/day DGL orally for six weeks), DGL + CTX group (treated with 500 mg/kg/day DGL orally plus 200 mg/kg/day CTX intraperitoneally for six weeks), and CTX group (treated with 200 mg/kg/day CTX intraperitoneally for six weeks). The liver and kidney function indices such as serum creatinine, blood urine nitrogen, alanine aminotransferase, and aspartate aminotransferase were measured. Also, levels of malondialdehyde, catalase, and glutathione peroxidase in hepatic and renal tissues were evaluated. Moreover, the expression profiles of interleukin 1 beta and tumor necrosis factor alpha were assessed. The liver and kidney tissues were assessed for histopathological lesions. The results showed that aging induced by DGL leads to abnormalities in functional indices of the liver and kidneys. DGL also induced significant oxidative stress and inflammation, as well as histopathological lesions, in these organs. CTX improved functional indices, as well as the parameters of oxidative stress and inflammation, compared with the DGL-treated animals. These results were also confirmed by histological evaluations of the liver and kidneys. These data provide evidence for the therapeutic value of CTX in clinical practice for mitigating the hepatorenal damages of aging.

Intra-Articular Route for the System of Molecules 14G1862 from Centella Asiatica: Pain Relieving and Protective Effects in a Rat Model of Osteoarthritis

Current pharmacological therapies for the management of chronic articular diseases are far from being satisfactory, so new strategies need to be investigated. We tested the intra-articular pain relieving properties of a system of molecules from a characterized Centella asiatica extract (14G1862) in a rat model of osteoarthritis induced by monoiodoacetate (MIA). 14G1862 (0.2–2 mg mL⁻¹) was intra-articularly (i.a.) injected 7 days after MIA, behavioural and histological evaluations were performed 14, 30 and 60 days after treatments. Moreover, the effect of 14G1862 on nitrate production and iNOS expression in RAW 264.7 macrophages stimulated with LPS was assessed. In vitro, 14G1862 treatment attenuated LPS-induced NO production and iNOS expression in a comparable manner to celecoxib. In vivo, 14G1862 significantly reduced mechanical allodynia and hyperalgesia, spontaneous pain and motor alterations starting on day 14 up to day 60. The efficacy was higher or comparable to that evoked by triamcinolone acetonide (100 μg i.a.) used as reference drug. Histological evaluation highlighted the improvement of several morphological parameters in MIA + 14G1862-treated animals with particularly benefic effects on joint space and fibrin deposition. In conclusion, i.a. treatment with Centella asiatica is a candidate to be a novel effective approach for osteoarthritis therapy.

Centella asiatica (Gotu kola) ethanol extract up-regulates hippocampal brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB) and extracellular signal-regulated protein kinase 1/2 (ERK1/2) signaling in chronic electrical stress model in rats

OBJECTIVES

Impairment of hippocampus function as a center for memory processing occurs due to stress. Centella asiatica L. (Gotu kola) is known to improve memory, intelligence, and neural protection although the precise mechanism is not well understood. This study aimed to investigate the effects of ethanol extracts of C. asiatica toward MAPK expression as down-stream signaling of brain-derived neurotrophic factor (BDNF).

MATERIALS AND METHODS

We performed a chronic electrical stress model on 20 male Sprague Dawley rats (2 months-old, 180-200 g). Rats were divided into four groups: normal control group (Control) which received distilled water, and three treatment groups receiving oral Gotu kola ethanol extracts in oral doses of 150 mg/kg BW (CeA150), 300 mg/kg BW (CeA300), and 600 mg/kg BW (CeA600) over four weeks. Memory acquisition was assessed with Morris water maze. Hippocampus was harvested, then extracted for protein and RNA analysis. MAPK proteins (p38, ERK1/2, JNK) were measured using Western blot, meanwhile, BDNF and TrkB receptor were analyzed with real-time PCR (RT-PCR).

RESULTS

CeA600 group revealed improvement of memory performance as shown by reduction in time and distance parameters compared to control during escape latency test. This finding associated with significant elevation of hippocampal BDNF protein and mRNA level with up-regulation of TrkB mRNA expression in CeA600 group compared to control. Western-blot analysis showed significant up-regulation of ERK1/2 protein level in CeA600 group (P<0.05) compare to control.

CONCLUSION

BDNF signaling through TrkB and ERK1/2 pathway contributes significantly to amelioration of memory performance after C. asiatica treatment in electrical stress model.

Comparison of three different extracts of Centella asiatica for anti-amnesic, antioxidant and anticholinergic activities: in vitro and in vivo study

Centella asiatica (CA) has been used by Ayurvedic medical practitioners in India for almost 3000 years. The neuropharmacological properties of CA and its constituents have been studied extensively. Anti-oxidant, free radical scavenging and cholinergic modulatory activities are the reported mechanisms of action for its efficacy in memory disorders. Its medicinal values are mainly attributed to the presence of several triterpenes, namely asiatic acid, madecassic acid, asiaticoside, and madecassoside. The present study was aimed to investigate the role of these triterpenes content in CA extract on the antioxidant, cholinesterase modulation and anti-amnesic properties. The fractions of CA extract enriched for (CAE-EF) and depleted/freed of (CAE-FF) triterpenes contents were compared with methanolic extract (CAE). Both in vitro and in vivo methods for evaluation of antioxidant and anticholinergic activities were used. In vitro, free radical scavenging assays (ABTS, DPPH, NO, NORAC, and ORAC) and cholinesterase (AChE and BuChE) inhibition assays were used. For evaluation of anti-amnesic effect, scopolamine induced amnesia in rats, as the acute model of memory loss was used. Following behavioural assessments (MWM, PA, EPM), biomarkers of oxidative stress (reduced GSH, MDA and SOD activity) and cholinesterase (AChE and BuChE) status were also estimated in cerebral cortex and hippocampus of rat brain. The methanolic extract (CAE) was found to perform best among all three fractions for in vitro free radical scavenging, cholinesterase inhibition, improvement of scopolamine-induced amnesia and also in vivo antioxidant effect and cholinesterase inhibitory activities. Interestingly triterpenes free fraction (CAE-FF) showed better antioxidant activity than triterpenes enriched fraction (CAE-EF) along with comparable anti-amnesic effect. This indicates that triterpenes are not solely responsible for antioxidant activity, cholinesterase inhibitory and anti-amnesic effect of CA.

Does caffeine influence the anticholinesterase and antioxidant properties of donepezil? Evidence from in vitro and in vivo studies

Caffeine is adjudged world's most consumed pharmacologically active food component. With reports of the potential cognitive enhancing properties of caffeine, we sought to investigate if caffeine can influence the anticholinesterase and antioxidant properties of donepezil-a selective acetylcholinesterase (AChE) inhibitor used in the management of Alzheimer's disease (AD). In vitro, we investigated the effect of donepezil (DON), caffeine (CAF) and their various combinations on the activity of AChE in rat brain homogenate, as well as determined their antioxidant properties. In vivo, two rat groups were administered single oral dose of DON (5 mg/kg) and CAF (5 mg/kg) separately, while three groups, each received 5 mg/kg DON plus either 5, 50 or 100 mg/kg CAF for three hours, after which the rats were sacrificed and brain isolated. Results show that CAF concentration dependently and synergistically increased the anticholinesterase properties of DON in vitro. Also, CAF produced a significant influence on investigated in vitro antioxidant properties of DON. Furthermore, rats administered 5 mg/kg CAF and DON produced no significant difference in AChE activity compared to rats administered DON alone. However, co-administration of either 50 or 100 mg/kg CAF with DON lead to higher AChE activity compared to both control and DON groups. In addition, DON, CAF and their various combinations augmented brain antioxidant status in treated rats. We conclude that while low caffeine consumption may improve the antioxidant properties of donepezil without having a significant influence on its anticholinesterase effect, moderate-high caffeine consumption could also improve the antioxidant properties of donepezil but reduce its anticholinesterase effect; nevertheless, a comprehensive clinical trial is essential to fully explore these possibilities in human AD condition.

Anti-Inflammatory Effect of Titrated Extract of Centella asiatica in Phthalic Anhydride-Induced Allergic Dermatitis Animal Model

Centella asiatica has potent antioxidant and anti-inflammatory properties. However, its anti-dermatitic effect has not yet been reported. In this study, we investigated the anti-dermatitic effects of titrated extract of Centella asiatica (TECA) in a phthalic anhydride (PA)-induced atopic dermatitis (AD) animal model as well as in vitro model. An AD-like lesion was induced by the topical application of five percent PA to the dorsal skin or ear of Hos:HR-1 mouse. After AD induction, 100 μL of 0.2% and 0.4% of TECA (40 μg or 80 μg/cm²) was spread on the dorsum of the ear or back skin three times a week for four weeks. We evaluated dermatitis severity, histopathological changes and changes in protein expression by Western blotting for inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and NF-κB activity, which were determined by electromobility shift assay (EMSA). We also measured TNF-α, IL-1β, IL-6, and IgE concentration in the blood of AD mice by enzyme-linked immunosorbent assay (ELISA). TECA treatment attenuated the development of PA-induced atopic dermatitis. Histological analysis showed that TECA inhibited hyperkeratosis, mast cells and infiltration of inflammatory cells. TECA treatment inhibited expression of iNOS and COX-2, and NF-κB activity as well as the release of TNF-α, IL-1β, IL-6, and IgE. In addition, TECA (1, 2, 5 μg/mL) potently inhibited Lipopolysaccharide (LPS) (1 μg/mL)-induced NO production, expression of iNOS and COX-2, and NF-κB DNA binding activities in RAW264.7 macrophage cells. Our data demonstrated that TECA could be a promising agent for AD by inhibition of NF-κB signaling.

Modulatory Effects of Decalepis hamiltonii Extract and Its Compounds on the Antioxidant Status of the Aging Rat Brain

OBJECTIVE

The present study was aimed to investigate the neuroprotective effects of Decalepis hamiltonii (Dh) aqueous root extract and its compounds against age-related oxidative stress (OS) in the discrete regions of the rat brain.

MATERIALS AND METHODS

Male Wistar albino rats of 4- and 22-month-old were divided into control and six supplemented groups. The supplemented groups were orally administered with ellagic acid (EA), 4-hydroxyisophthalic acid (4-HIA), and Dh extract for 30 days.

RESULTS

Age-related decrease in antioxidant enzyme activities was noticed. The hippocampus was found to be more vulnerable to OS as seen by the elevation in the OS markers. Supplementation of the Dh extract, EA, and 4-HIA was found to be effective in up-regulating the antioxidant status. However, the extent of up-regulation was more evident in Dh supplemented animals.

CONCLUSION

Our results suggest that Dh extract and its compounds exhibit neuroprotective effects against age-related OS and can be used as a dietary therapeutic intervention for the treatment of neurological disorders.

Centella asiatica modulates antioxidant and mitochondrial pathways and improves cognitive function in mice

ETHNOPHARMACOLOGICAL RELEVANCE

This study investigates the cognitive enhancing effects of the plant Centella asiatica which is widely used Ayurvedic and traditional Chinese medicine.

AIM OF THE STUDY

The goal of this study was to determine the effects of a water extract of the medicinal plant Centella asiatica (CAW) on cognitive ability as well as mitochondrial and antioxidant response pathways in vivo.

MATERIALS AND METHODS

Old and young C57BL/6 mice were treated with CAW (2mg/mL) in their drinking water. Learning and memory was assessed using Morris Water Maze (MWM) and then tissue was collected and gene expression analyzed.

RESULTS

CAW improved performance in the MWM in aged animals and had a modest effect on the performance of young animals. CAW also increased the expression of mitochondrial and antioxidant response genes in the brain and liver of both young and old animals. Expression of synaptic markers was also increased in the hippocampus and frontal cortex, but not in the cerebellum of CAW-treated animals.

CONCLUSIONS

These data indicate a cognitive enhancing effect of CAW in healthy mice. The gene expression changes caused by CAW suggest a possible effect on mitochondrial biogenesis, which in conjunction with activation of antioxidant response genes could contribute to cognitive improvement.

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.

Gotu Kola (Centella asiatica): Nutritional Properties and Plausible Health Benefits

Centella asiatica L. (Gotu Kola) is a nutritionally important plant and a valued traditional medicine in South East Asia. In this review, the chemical composition, nutritional values, and health benefits of C. asiatica have been discussed in detail to emphasize its usage as traditional food and medicine. C. asiatica is one of the most commonly used green leafy vegetables (GLVs) in some countries including Sri Lanka due to its high amounts of medicinally important triterpenoids and beneficial carotenoids. It is consumed in the form of GLVs and in the preparation of juice, drink, and other food products. It is also known to contain vitamins B and C, proteins, important minerals, and some other phytonutrients such as flavonoids, volatile oils, tannins, and polyphenol. In vitro and in vivo studies have shown important health benefits like antidiabetic, wound-healing, antimicrobial, memory-enhancing, antioxidant, and neuroprotecting activities. However, detailed scientific approaches on clinical trials regarding health benefits and nutritional values of C. asiatica are limited, hindering the perception of its benefits, mechanisms, and toxicity in order to develop new drug prototypes. In vitro studies have shown that the method of processing C. asiatica has an impact on its nutritional values and health-related beneficial compounds. The composition of its compounds is influenced by different biotic and abiotic factors which need to be studied in detail to provide information to the public in order to maximize the usage of this valuable plant.

Centella asiatica extract protects against amyloid β1-40-induced neurotoxicity in neuronal cells by activating the antioxidative defence system

Centella asiatica (雷公根 léi gōng gēn) is a traditional medicinal herb with high antioxidant activity, which decreases amyloid-β (Aβ) deposition in the brain. At the same time, aggregated Aβ-induced oxidative stress is the trigger in the pathogenesis of Alzheimer's disease (AD). Here, we investigated the ability of C. asiatica ethanol extract (CAE) to protect PC12 and IMR32 cells from Aβ_1–40-induced production of reactive oxygen species (ROS) and concomitant neurotoxicity. Aggregated Aβ_1–40 treatment resulted in reduced cell viability, which can be reversed by cotreatment with 25, 50, and 100 μg/mL CAE. Moreover, CAE eliminated the Aβ_1–40-mediated increase in ROS production. Thus, CAE-mediated protection against aggregated Aβ_1–40-induced neurotoxicity is attributable to modulation of the antioxidative defense system in cells, including the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and levels of glutathione and glutathione disulfide by CAE. This emphasizes the potential therapeutic and preventive value of CAE in the treatment of AD.

Protective roles of N-benzylcinnamide on cortex and hippocampus of aged rat brains

Brain aging has been associated with oxidative stress leading to inflammation and apoptosis. The protective effects and underlying mechanisms of N-benzylcinnamide (PT-3), purified from Piper submultinerve, on brains of 90-week-old Wistar rats were investigated following daily intraperitoneal injection with 1.5 mg of PT-3/kg of body weight for 15 days. PT-3 treatment improved spatial learning and memory of aged rats and caused significant changes in brain frontal cortex, hippocampus, and temporal cortex in parameters associated with oxidative stress (decreased reactive oxygen species production and iNOS and nNOS levels), inflammation (reduced levels of IL-1β and IL-6), apoptosis (reduced levels of Bax and activated caspase-3, and elevated level of Bcl-2), and signaling pathways related to inflammation and apoptosis (decreased amounts of phospho-JNK and -p38, increased phospho-Akt level and no change in phospho-ERK1/2 content) compared to controls. PT-3 treatment also inhibited aged rat brain AChE activity. These results suggest that PT-3 with its intrinsic antioxidant and AChE inhibitory properties has therapeutic potential in ameliorating, in part, age-associated damages to the brain.

A molecular docking study of phytochemical estrogen mimics from dietary herbal supplements

PURPOSE

The purpose of this study is to use a molecular docking approach to identify potential estrogen mimics or anti-estrogens in phytochemicals found in popular dietary herbal supplements.

METHODS

In this study, 568 phytochemicals found in 17 of the most popular herbal supplements sold in the United States were built and docked with two isoforms of the estrogen receptor, ERα and ERβ (a total of 27 different protein crystal structures).

RESULTS

The docking results revealed six strongly docking compounds in Echinacea, three from milk thistle (Silybum marianum), three from Gingko biloba, one from Sambucus nigra, none from maca (Lepidium meyenii), five from chaste tree (Vitex agnus-castus), two from fenugreek (Trigonella foenum-graecum), and two from Rhodiola rosea. Notably, of the most popular herbal supplements for women, there were numerous compounds that docked strongly with the estrogen receptor: Licorice (Glycyrrhiza glabra) had a total of 26 compounds strongly docking to the estrogen receptor, 15 with wild yam (Dioscorea villosa), 11 from black cohosh (Actaea racemosa), eight from muira puama (Ptychopetalum olacoides or P. uncinatum), eight from red clover (Trifolium pratense), three from damiana (Turnera aphrodisiaca or T. diffusa), and three from dong quai (Angelica sinensis). Of possible concern were the compounds from men's herbal supplements that exhibited strong docking to the estrogen receptor: Gingko biloba had three compounds, gotu kola (Centella asiatica) had two, muira puama (Ptychopetalum olacoides or P. uncinatum) had eight, and Tribulus terrestris had six compounds.

CONCLUSIONS

This molecular docking study has revealed that almost all popular herbal supplements contain phytochemical components that may bind to the human estrogen receptor and exhibit selective estrogen receptor modulation. As such, these herbal supplements may cause unwanted side effects related to estrogenic activity.

Ozone ameliorates age-related oxidative stress changes in rat liver and kidney: effects of pre- and post-ageing administration

The ageing process is known to be accompanied by increased oxidative stress and compromised antioxidant defenses. Controlled ozone administration has been shown to be effective in various pathophysiological conditions with an underlying oxidative burden. However, its effect on the biochemical alterations associated with the ageing process has been rarely studied. Therefore, the present work was carried out to study the role of ozone in counteracting the state of oxidative stress associated with ageing in rat liver and kidneys using two experimental models. In the pre-ageing model, ozone was administered prior to the onset of ageing at adulthood and continued after the start of the ageing process (3-month-old rats until the age of 15 months). While in the post-ageing model, ozone was administered after ageing has begun and lasted for one month (14-month-old rats until the age of 15 months). The pre-ageing ozone administration effectively reduced lipid and protein oxidation markers, namely, malondialdehyde and protein carbonyl levels and decreased lipofuscin pigment deposition in rat liver and kidneys. Moreover, it significantly restored hepatic and renal reduced glutathione (GSH) contents and normalized cytosolic hepatic glutathione peroxidase activity. Similar but less pronounced effects were observed in the post-ageing ozone-treated group. Nevertheless, in the latter model ozone administration failed to significantly affect liver and kidney lipofuscin levels, as well as kidney GSH contents. These data provide evidences for potentially positive effects of pre-ageing ozone therapy in neutralizing chronic oxidative stress associated with ageing in rat liver and kidneys.

Effect of Centella asiatica Leaf Extract on the Dietary Supplementation in Transgenic Drosophila Model of Parkinson's Disease

The role of Centella asiatica L. leaf extract was studied on the transgenic Drosophila model flies expressing normal human alpha synuclein (h-αS) in the neurons. The leaf extract was prepared in acetone and was subjected to GC-MS analysis. C. asiatica extract at final concentration of 0.25, 0.50, and 1.0 μL/mL was mixed with the diet and the flies were allowed feeding on it for 24 days. The effect of extract was studied on the climbing ability, activity pattern, lipid peroxidation, protein carbonyl content, glutathione content, and glutathione-S-transferase activity in the brains of transgenic Drosophila. The exposure of extract to PD model flies results in a significant delay in the loss of climbing ability and activity pattern and reduced the oxidative stress (P < 0.05) in the brains of PD flies as compared to untreated PD flies. The results suggest that C. asiatica leaf extract is potent in reducing the PD symptoms in transgenic Drosophila model of Parkinson's disease.

Centella asiatica in dermatology: an overview

Centella asiatica is a medicinal plant that was already used as a 'panacea' 3000 years ago. The active compounds include pentacyclic triterpenes, mainly asiaticoside, madecasosside, asiatic acid and madecassic acid. We have conducted an overview to summarize current knowledge on the results of scientific in vitro and in vivo experiments focused on the improvement of the healing process of small wounds, hypertrophic scars and burns by C. asiatica. In this paper, we discuss the data on constituents, recommended preparations and the potential side effects of C. asiatica.

Changing scenario for promotion and development of Ayurveda--way forward

ETHNOPHARMACOLOGICAL RELEVANCE

Ayurveda, derives from the Sanskrit words Ayus (life) and Veda (knowledge) is the most ancient system of traditional medicine of the world. It has been practiced in Indian peninsula since 5000 BC to offer natural ways to treat diseases and to promote healthcare.

METHODOLOGY

We reviewed the literature on the history, principles and current status of Ayurveda. The data have been presented systematically including the initiatives from Government of India. Several aspects of administrative management, education, teaching and related aspects for promotion and development of Ayurveda and other Indian systems of traditional medicine have been discussed.

RESULTS

This paper reviews on different aspects of development of Ayurveda. Presently, there are 2420 hospitals with about 42271 beds, 15017 dispensaries, 429246 registered practitioners, more than 320 educational institutions, 7699 drug-manufacturing units to promote Ayurveda into the health care delivery system in the country. Ayurvedic Pharmacopoeia of India is the official document for single Ayurvedic drugs (540 monographs) and different formulations (152 monographs). Several aspects in this regard for development of Ayurveda have been discussed.

CONCLUSION

Considering the widespread use and popularity of Ayurveda worldwide, administrative management and infrastructure facilities, indigenous practices and standards for quality control and it's evaluation have been highlighted. In India, all such efforts for integration of Ayurveda provide potential role in the health care benefits.

The potential role of ozone in ameliorating the age-related biochemical changes in male rat cerebral cortex

Controlled ozone (O(3)) administration is known to promote oxidative preconditioning and, thus, may reverse chronic oxidative stress that accompanies aging. Therefore, the present work was undertaken to study the potential role of O(3) in ameliorating certain age-related biochemical changes represented by impaired activities of inner mitochondrial membrane enzymes, compromised energy production and increased oxidative burden in male rat cerebral cortex. Prophylactic administration of O(3)-O(2) mixture to 3 month-old rats, at an intrarectal dose of 0.6 mg O(3) kg(-1) body weight twice/week for 3 months then once/week until the age of 15 months, normalized reduced glutathione content, adenosine triphosphate/adenosine diphosphate ratio, mitochondrial superoxide dismutase (SOD) and complex IV (cytochrome-c oxidase) activities, improved glutathione redox index (GSHRI), complex I (NADH-ubiquinone oxidoreductase) and mitochondrial nitric oxide synthase (mtNOS) activities, and attenuated the rise in malondialdehyde (MDA) and mitochondrial protein carbonyl levels. On the other hand, therapeutic administration of the same dose of O(3)-O(2) mixture to 14 month-old rats three times/week for 1 month, reduced mitochondrial protein carbonyl level only. Other favorable effects, including normalization of Na,K-adenosine triphosphatase (Na,K-ATPase) activity and reduction in lipofuscin level in the prophylactic group, as well as improvement in mitochondrial SOD and complex I activities with a decrease in total MDA level in the therapeutic group, were comparable to the effects observed in the corresponding O(2)-treated control groups. In conclusion, the present study revealed that prophylactic administration of O(3)-O(2) mixture provided better amelioration of age-related cerebrocortical alterations by combining the advantages of both O(3) and O(2) therapies.

Factors affecting the content of pentacyclic triterpenes in Centella asiatica raw materials

CONTEXT

Pentacyclic triterpenes, mainly, asiatic acid, madecassic acid, asiaticoside, and madecassoside are the active constituents of Centella asitica (L.) Urban. (Apiaceae). These compounds possess various pharmacological activities that have been shown to assist with wound healing and brain enrichment.

OBJECTIVE

Determination of these active pentacyclic triterpenes in extracts from the various parts of C. asiatica plants harvested at different times of the year and grown in different environments.

MATERIALS AND METHODS

The separate plant parts selected were leaves, stolons, petioles, flowers, fruits, and nodes with roots. Dried powder from each part was extracted with ethanol by microwave-assisted extraction and subjected to determination of their content of the four pentacyclic triterpenes using a HPLC method. The effects of the places of cultivation as well as harvesting periods on the content of the four pentacyclic triterpenes in the extracts were also determined.

RESULTS AND DISCUSSION

Among the various parts of C. asiatica, the leaves contained the highest amount of pentacyclic triterpenes with a total content of pentacyclic triterpenes of 19.5 mg/g dry powder. However, the contents of the pentacyclic triterpenes in C. asiatica varied according to the place of cultivation and the harvesting period. C. asiatica collected from Trang, Thailand gave the highest content of total pentacyclic triterpenes (37.2 mg/g dry powder) when harvested in March, while those collected from Songkhla, Thailand gave the highest value (37.4 mg/g dry powder) when collected in December. C. asiatica collected from Nakornsrithammarat and Ratchaburi, Thailand gave the lowest content of total pentacyclic triterpenes in all experimental harvesting periods.

Protective role of Centella asiatica on lead-induced oxidative stress and suppressed reproductive health in male rats

Centella asiatica has been mentioned in ancient ayurvedic text of the Indian system of medicine for its properties to promote intelligence. The objective of the present study was to investigate the beneficial effects of C. asiatica on lead-induced oxidative stress and suppressed reproductive performance in male rats. Significant decrease in the weights of testes and epididymis were observed in lead treated animals. Exposure to lead acetate significantly increased malondialdehyde levels with a significant decrease in the superoxide dismutase and catalase activities in the liver, brain, kidneys and testes of rats. Epididymal sperm count, viable sperms, motile sperms and HOS-tail coiled sperms decreased significantly in lead-exposed rats. Testicular steroidogenic enzyme activities also decreased significantly in lead-exposed rats. No significant changes in the selected reproductive variables were observed in the plant extract alone treated rats. Whereas, co-administration of aqueous extracts of C. asiatica to lead exposed rats showed a significant increase in the weights of reproductive organs, reduction in lead-induced oxidative stress in the tissues and improvement in selected reproductive parameters over lead-exposed rats indicating the beneficial role of C. asiatica to counteract lead-induced oxidative stress and to restore the suppressed reproduction in male rats.

Differential antioxidant effects of consuming tea from Sideritis clandestina subsp. peloponnesiaca on cerebral regions of adult mice

Oxidative stress is involved in the pathophysiology of neurodegenerative diseases and aging. Many species of the genus Sideritis (mountain tea) are widely consumed in the Mediterranean region as herbal tea. This study evaluated the effect of supplementation of mice with herbal tea from Sideritis clandestina subsp. peloponnesiaca on the antioxidant status of different brain regions. To select the most bioactive herbal tea, the polyphenolic content (Folin-Ciocalteu method) and the antioxidant properties (ferric reducing antioxidant power [FRAP] and 2,2-diphenyl-1-picrylhydrazyl assays) of several taxa and different populations of the S. clandestina infusions were measured in vitro. Male adult mice had ad libitum access to water (control) or the herbal tea (4% w/v) for 6 weeks. At the end of the treatment period we assessed the total antioxidant power (FRAP assay) and the levels of malondialdehyde (indicator of lipid peroxidation) and reduced glutathione in the cerebral cortex, cerebellum, and midbrain. These biochemical measures have also been determined in liver samples used as a comparative reference peripheral tissue. Consumption of 4% herbal tea increased the total antioxidant power of the midbrain by 72% (P<.05); a significant (P<.05) decrease in malondialdehyde levels and increase in reduced glutathione content of the cerebellum (78% and 27%, respectively) and midbrain (59% and 32%, respectively) were also observed. These findings indicate that mountain tea consumption enhances the antioxidant defense of the adult rodent brain in a region-specific manner.

Triterpene composition and bioactivities of Centella asiatica

Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination of asiatic acid, madecassic acid, asiaticoside and madecassoside. Centella was found to contain significant amounts of madecassoside (3.10 ± 4.58 mg/mL) and asiaticoside (1.97 ± 2.65 mg/mL), but was low in asiatic and madecassic acid. The highest collagen synthesis was found at 50 mg/mL of Centella extracts. The antioxidant activity of Centella (84%) was compared to grape seed extract (83%) and Vitamin C (88%). Its lipolytic activity was observed by the release of glycerol (115.9 µmol/L) at 0.02% concentration. Centella extracts exhibited similar UV protection effect to OMC at 10% concentration. In view of these results, the potential application of Centella in food and pharmaceutical industries is now widely open.

Neuroprotective effect of Centella asiatica extract (CAE) on experimentally induced parkinsonism in aged Sprague-Dawley rats

Reactive oxygen species (ROS) play an important role in ageing and age-related neurodegenerative changes including Parkinson's disease (PD). PD is characterized by signs of major oxidative stress and mitochondrial damage in the pars compacta of the substantia nigra. Present study was designed to investigate whether the Centella asiatica extract (CAE) would prevent 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in aged Sprague-Dawley rats. Adult, male Sprague-dawley rats of 300-350 g were divided into control, C. asiatica alone, MPTP alone (20 mg/kg, for 21 days) and MPTP with C. asiatica (300 mg/kg for 21 days) groups. Effect of aqueous extract of C. asiatica on oxidative biomarker levels in corpus striatum and hippocampus homogenate was examined. MPTP-challenged rats elicited a significant increase in lipid hydroperoxides (LPO) (p < 0.01), protein-carbonyl-content (PCC) (p < 0.01) and xanthine oxidase (XO) (p < 0.01) when compared with control rats. There was a significant decrease in total antioxidants (TA) (p < 0.001), superoxide dismutase (SOD) (p < 0.001), glutathione peroxidase (GPx) (p < 0.01) and catalase (CAT) (p < 0.001) levels with MPTP treatment. Supplementation of CAE reduced LPO and PCC and significantly increased (p < 0.01) TA and antioxidant enzyme levels (p < 0.01) in corpus striatum and hippocampus. These results show that administration of C. asiatica was effective in protecting the brain against neurodegenerative disorders such as Parkinsonism.

Asiatic acid, a pentacyclic triterpene from Centella asiatica, is neuroprotective in a mouse model of focal cerebral ischemia

Asiatic acid, a triterpenoid derivative from Centella asiatica, has shown biological effects such as antioxidant, antiinflammatory, and protection against glutamate- or beta-amyloid-induced neurotoxicity. We investigated the neuroprotective effect of asiatic acid in a mouse model of permanent cerebral ischemia. Various doses of asiatic acid (30, 75, or 165 mg/kg) were administered orally at 1 hr pre- and 3, 10, and 20 hr postischemia, and infarct volume and behavioral deficits were evaluated at day 1 or 7 postischemia. IgG (blood-brain barrier integrity) and cytochrome c (apoptosis) immunostaining was carried out at 24 hr postischemia. The effect of asiatic acid on stress-induced cytochrome c release was examined in isolated mitochondrial fractions. Furthermore, its effects on cell viability and mitochondrial membrane potential were studied in HT-22 cells exposed to oxygen-glucose deprivation. Asiatic acid significantly reduced the infarct volume by 60% at day 1 and by 26% at day 7 postischemia and improved neurological outcome at 24 hr postischemia. Our studies also showed that the neuroprotective properties of asiatic acid might be mediated in part through decreased blood-brain barrier permeability and reduction in mitochondrial injury. The present study suggests that asiatic acid may be useful in the treatment of cerebral ischemia.

Antioxidant and cytotoxic activities of Centella asiatica (L) Urb

In the present study, the phenolic (Folin-Dennis) and flavonoid (colorimetric assay) constituents, antioxidant [2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay] and cytotoxic activities of an aqueous extract (AE) of Centella asiatica leaves were investigated. The aqueous extract (50 g/L) was obtained by infusion followed by cold maceration for 24 h. The levels of phenolic and flavonoid compounds were 2.86 g/100 g and 0.361 g/100 g, respectively. The AE showed elevated DPPH scavenging activity, with an IC₅₀ value of 31.25 μg/mL. The AE had a promising activity against mouse melanoma (B₁₆F₁), human breast cancer (MDA MB-231) and rat glioma (C₆) cell lines, with IC₅₀ values of 698.0, 648.0 and 1000.0 μg/mL, respectively. A positive correlation was established between the level of flavonoids, antioxidant and antitumor activities.

Centella asiatica extract selectively decreases amyloid beta levels in hippocampus of Alzheimer's disease animal model

PSAPP mice expressing the 'Swedish' amyloid precursor protein and the M146L presenilin 1 mutations are a well-characterized model for spontaneous amyloid beta plaque formation. Centella asiatica has a long history of use in India as a memory enhancing drug in Ayurvedic literature. The study investigated whether Centella asiatica extract (CaE) can alter the amyloid pathology in PSAPP mice by administering CaE (2.5 or 5.0 g/kg/day) starting at 2 months of age prior to the onset of detectable amyloid deposition and continued for either 2 months or 8 months. A significant decrease in amyloid beta 1-40 and 1-42 was detectable by ELISA following an 8 month treatment with 2.5 mg/kg of CaE. A reduction in Congo Red stained fibrillar amyloid plaques was detected with the 5.0 mg/kg CaE dose and long-term treatment regimen. It was also confirmed that CaE functions as an antioxidant in vitro, scavenging free radicals, reducing lipid peroxidation and protecting against DNA damage. The data indicate that CaE can impact the amyloid cascade altering amyloid beta pathology in the brains of PSAPP mice and modulating components of the oxidative stress response that has been implicated in the neurodegenerative changes that occur with Alzheimer's disease.

Centella asiatica water extract inhibits iPLA2 and cPLA2 activities in rat cerebellum

Centella asiatica (L.) Urb an is distributed widely in South America and Asia and is known as a therapeutic agent in folk medicine, capable of improving memory and treating several neurological disorders. Asiaticoside is one of the compounds found in C. asiatica leaves that is suggested to be responsible for its pharmacological potential. Phospholipase A(2) (PLA(2)) is a group of enzymes that has abnormal activity in the central nervous system in some neuropsychiatric diseases. In this work, the asiaticoside present in C. asiatica water extract was quantified by HPLC analysis. We also evaluated the activity of subtypes of PLA(2) in cerebellar samples from rats after C. asiatica water extract treatment using a radioenzymatic assay. Asiaticoside was the major compound (84%) found in Centella water extract. We found a dose-dependent inhibitory effect of C. asiatica water extract on the activity of Ca(2+)-independent PLA(2) (iPLA(2)) and cytosolic PLA(2) (cPLA(2)). The inhibition of these enzymes in the brain suggests that C. asiatica may be useful to treat conditions associated with increased PLA(2) activity in the brain, such as epilepsy, stroke, multiple sclerosis and other neuropsychiatric disorders.

Positive modulation of cognition and mood in the healthy elderly volunteer following the administration of Centella asiatica

AIMS OF THIS STUDY

Centella asiatica has a reputation to restore decline cognitive function in traditional medicine and in animal model. However, little evidence regarding the efficacy of Centella asiatica from systematized trials is available. Therefore, the present randomized, placebo-controlled, double-blind study investigated the effect of Centella asiatica on cognitive function of healthy elderly volunteer.

MATERIALS AND METHODS

Twenty-eight healthy elderly participants received the plant extract at various doses ranging 250, 500 and 750 mg once daily for 2 months. Cognitive performance was assessed using the computerized test battery and event-related potential whereas mood was assessed using Bond-Lader visual analogue scales prior to the trial and after single, 1 and 2 months after treatment.

RESULTS

The results showed that the high dose of the plant extract enhanced working memory and increased N100 component amplitude of event-related potential. Improvements of self-rated mood were also found following the Centella asiatica treatment.

CONCLUSION

Therefore, the present findings suggest the potential of Centella asiatica to attenuate the age-related decline in cognitive function and mood disorder in the healthy elderly. However, the precise mechanism(s) underlying these effects still require further investigation.

Beneficial effects of Centella asiatica aqueous extract against arsenic-induced oxidative stress and essential metal status in rats

The efficacy of an aqueous extract of Centella asiatica (100, 200 and 500 mg/kg for 5 consecutive days) was studied in the depletion of arsenic and in the recovery of a few altered biochemical variables in arsenic pre-exposed rats (20 ppm in drinking water for 5 weeks). Exposure to arsenic significantly depleted delta-aminolevulinic acid dehydratase (ALAD) activity, reduced glutathione (GSH) level, superoxide dismutase (SOD) and increased thiobarbituric acid reactive substance (TBARS) activity in red blood cells. Significant depletion of ALAD activity, GSH level, glutathione peroxidase (GPx), SOD and catalase (CAT) activities and an increase in TBARS levels in liver tissues was also noted. There was a significant depletion of SOD, CAT and GPx activities in kidneys and an increased TBARS levels in kidney and brain accompanied by increased arsenic concentration in blood and soft tissues. Treatment with aqueous extract of Centella asiatica provided significant protection against ALAD, GSH and TBARS levels, particularly at doses of 200 and 500 mg. Centella asiatica also provided significant recovery in the inhibited liver ALAD and G6PD activities. Arsenic concentration in blood and soft tissues remained uninfluenced after Centella asiatica administration. The present study thus suggests a beneficial effect of Centella asiatica against arsenic-induced oxidative stress but possesses no chelating property.

Age-Associated Oxidative Macromolecular Damages in Rat Brain Regions: Role of Glutathione Monoester

The generation of reactive oxygen species (ROS) and resultant oxidative stress has been implicated in the mechanism of brain dysfunction due to age-related neurodegenerative diseases. We have evaluated the efficacy of glutathione monoester (GME) when administered intraperitoneally (12 mg/kg body weight) for 20 days on glutathione, ROS, superoxide anion production, lipid peroxidation (LPO), protein carbonyls, thiol status, oxidative DNA damage products such as 8-hydroxy deoxy guanosine and DNA protein cross-links in discrete brain regions of young and aged rats. An age associated increase in ROS, superoxide anion production, LPO, protein oxidation, and DNA damage products in cortex, striatum, and hippocampus was observed which was reversed by GME. Contradictorily, a decline in the levels of glutathione, total thiol, and nonprotein and protein thiols was observed which was also reversed upon GME administration. These findings suggest that GME administration inhibits free radical-induced oxidative macromolecular damage in aged rats and thereby protects the brain from ROS.

Current status of herbal drugs in India: an overview

Herbal drugs constitute a major share of all the officially recognised systems of health in India viz. Ayurveda, Yoga, Unani, Siddha, Homeopathy and Naturopathy, except Allopathy. More than 70% of India's 1.1 billion population still use these non-allopathic systems of medicine. Currently, there is no separate category of herbal drugs or dietary supplements, as per the Indian Drugs Act. However, there is a vast experiential-evidence base for many of the natural drugs. This offers immense opportunities for Observational Therapeutics and Reverse Pharmacology. Evidence-based herbals are widely used in the diverse systems and manufactured, as per the pharmacopoeial guidelines, by a well-organised industry. Significant basic and clinical research has been carried out on the medicinal plants and their formulations, with the state-of-the-art methods in a number of Institutes/Universities. There are some good examples. Indian medicinal plants also provide a rich source for antioxidants that are known to prevent/delay different diseased states. The antioxidant protection is observed at different levels. The medicinal plants also contain other beneficial compounds like ingredients for functional foods. Hence, the global knowledge about Ayurveda and Indian herbals will hopefully be enhanced by information on the evidence-base of these plants. This will yield rich dividends in the coming years.