Asiaticoside: attenuation of neurotoxicity induced by MPTP in a rat model of Parkinsonism via maintaining redox balance and up-regulating the ratio of Bcl-2/Bax

Optimization of Parkinson's disease therapy with plant extracts and nutrition's evolving roles

Parkinson's disease (PD) is a neurodegenerative disease characterized by death of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Death of dopaminergic cells in the SNpc leads to manifestations of motor dysfunction and non-motor symptoms of PD. The progression of PD symptoms severely affects the quality of life of patients and poses socio-economic problems to families and society at large. The clinical and neuropathological characteristics of PD are triggered by multiple factors such as oxidative stress, neuroinflammation, mitochondrial dysfunction, and protein aggregation. Notwithstanding the advancements in pharmacological therapy in PD management, there is burgeoning interest in alternative and complementary approaches, essentially nutrition and plant extracts strategies. This review gives widespread analysis of the role of nutrition and plant extracts in the management of PD. Studies that investigated the effects of various dietary compounds and plant extract on PD symptoms and progression were reviewed from existing literatures. Nutraceuticals, including vitamins and phytochemicals such as Mucuna pruriens have shown potential neuroprotective functions in preclinical and clinical studies. Indeed, these strategies ameliorate mitochondrial dysfunction, oxidative stress, and neuroinflammation, all which are implicated in the pathogenesis of PD. The neuroprotective mechanisms of nutrition and plant extracts in PD, with emphasis on their capacity to target multiple pathways implicated in PD are discussed. Additionally, challenges and limitations related with translating preclinical findings into clinical practice including standardization of dosing regimens, bioavailability, and inter-individual variability are discussed. Largely, this review elucidates on the role of nutrition and plant extracts as adjunctive therapy in PD management.

Asiaticoside exerts neuroprotection through targeting NLRP3 inflammasome activation

BACKGROUND

Parkinson's disease (PD), a neurodegenerative disorder, is characterized by motor symptoms due to the progressive loss of dopaminergic neurons in the substantia nigra (SN) and striatum (STR), alongside neuroinflammation. Asiaticoside (AS), a primary active component with anti-inflammatory and neuroprotective properties, is derived from Centella asiatica. However, the precise mechanisms through which AS influences PD associated with inflammation are not yet fully understood.

PURPOSE

This study aimed to explore the protective mechanism of AS in PD.

METHODS

Targets associated with AS and PD were identified from the Swiss Target Prediction, Similarity Ensemble Approach, PharmMapper, and GeneCards database. A protein-protein interaction (PPI) network was constructed to identify potential therapeutic targets. Concurrently, GO and KEGG analyses were performed to predict potential signaling pathways. To validate these mechanisms, the effects of AS on 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD in mice were investigated. Furthermore, neuroinflammation and the activation of the NLRP3 inflammasome were assessed to confirm the anti-inflammatory properties of AS. In vitro experiments in BV2 cells were then performed to investigate the mechanisms of AS in PD. Moreover, CETSA, molecular docking, and molecular dynamics simulations (MDs) were performed for further validation.

RESULTS

Network pharmacology analysis identified 17 potential targets affected by AS in PD. GO and KEGG analyses suggested the biological roles of these targets, demonstrating that AS interacts with 149 pathways in PD. Notably, the NOD-like receptor signaling pathway was identified as a key pathway mediating AS's effect on PD. In vivo studies demonstrated that AS alleviated motor dysfunction and reduced the loss of dopaminergic neurons in MPTP-induced PD mice. In vitro experiments demonstrated that AS substantially decreased IL-1β release in BV2 cells, attributing this to the modulation of the NLRP3 signaling pathway. CETSA and molecular docking studies indicated that AS forms a stable complex with NLRP3. MDs suggested that ARG578 played an important role in the formation of the complex.

CONCLUSION

In this study, we first predicted that the potential target and pathway of AS's effect on PD could be NLRP3 protein and NOD-like receptor signaling pathway by network pharmacology analysis. Further, we demonstrated that AS could alleviate symptoms of PD induced by MPTP through its interaction with the NLRP3 protein for the first time by in vivo and in vitro experiments. By binding to NLRP3, AS effectively inhibits the assembly and activation of the inflammasome. These findings suggest that AS is a promising inhibitor for PD driven by NLRP3 overactivation.

Sub-chronic oral toxicity of a water-soluble extract of Centella asiatica (Centell-S) in Wistar rats

BACKGROUND

Centell-S, a water-soluble extract from Centella asiatica, is predominantly composed of madecassoside and asiaticoside, exceeding 80% w/w. Pursuing its development as an herbal medicinal product, Centell-S underwent sub-chronic toxicity assessment adhering to OECD GLP 408 standards.

METHODS

In a study involving 100 Wistar rats, varying doses of Centell-S (50, 200, or 800 mg/kg/day) or a vehicle control were administered orally over 90 days. To evaluate Centell-S's safety profile, assessments included clinical observations, health examinations, clinical biochemistry analyses, and detailed anatomical pathology evaluations were conducted.

RESULTS

Over the 90 days of treatment, the administration of Centell-S did not lead to any fatalities in the test animals. Clinical observations did not reveal any signs indicative of toxic effects. Notably, an increase in total white blood cell and lymphocyte counts was observed in both sexes, yet these levels returned to normal following a two-week discontinuation period post-treatment.

CONCLUSIONS

Under the specific conditions of the OECD GLP 408, Repeated Dose 90-day Oral Toxicity Study in Rodents, the no observed adverse effect level (NOAEL) of Centell-S was 800 mg/kg/day. These findings are promising for the continued development of Centell-S as a phytopharmaceutical for clinical applications.

The neuroprotective effect of traditional Chinese medicinal plants-A critical review

Neurodegenerative and neuropsychiatric diseases are increasingly affecting individuals' quality of life, thus increasing their cost to social and health systems. These diseases have overlapping mechanisms, such as oxidative stress, protein aggregation, neuroinflammation, neurotransmission impairment, mitochondrial dysfunction, and excitotoxicity. Currently, there is no cure for neurodegenerative diseases, and the available therapies have adverse effects and low efficacy. For neuropsychiatric disorders, such as depression, the current therapies are not adequate to one-third of the patients, the so-called treatment-resistant patients. So, searching for new treatments is fundamental. Medicinal plants appear as a strong alternative and complement towards new treatment protocols, as they have been used for health purposes for thousands of years. Thus, the main goal of this review is to revisit the neuroprotective potential of some of the most predominant medicinal plants (and one fungus) used in traditional Chinese medicine (TCM), focusing on their proven mechanisms of action and their chemical compositions, to give clues on how they can be useful against neurodegeneration progression.

A review of pharmacokinetic and pharmacological properties of asiaticoside, a major active constituent of Centella asiatica (L.) Urb

ETHNOPHARMACOLOGICAL RELEVANCE

Centella asiatica (L.) Urb., a potential medicinal plant, is widely used in orient traditional medicine. Its major active constituents include asiaticoside (AS), madecassoside (MS), asiatic acid and madecassic acid. Thereinto, AS is a pentacyclic triterpenoid saponin with a variety of pharmacological effects including antitumor, neuroprotective and wound healing effects.

AIM OF THE STUDY

In this review, we summarize the pharmacokinetics, safety and pharmacological properties of AS.

MATERIALS AND METHODS

We gathered information about AS from articles published up to 2022 and listed in Google scholar, PubMed, Web of Science, Elsevier, and similar databases. The keywords used in our search included "asiaticoside", "Centella asiatica", "pharmacokinetics", "nerve", "cancer", "skin", etc. RESULTS: AS appeared to degrade through a first-order reaction and had low biotoxicity. However, the pharmacokinetic properties of AS differed according to species. AS is highly blood-brain-barrier permeable without any harmful side effect. It has a variety of pharmacological effects including anti-neural inflammation and anti-cancer properties, as well as protective properties for the skin, cardiovascular system, and pulmonary system.

CONCLUSION

This review comprehensively summarized current information regarding the pharmacokinetic and pharmacological properties of AS, and supported the pharmaceutical value of this compound. Future research should focus on improving bioavailability of AS and conducting clinical assessment.

Therapeutic properties and pharmacological activities of asiaticoside and madecassoside: A review

Centella asiatica is an ethnomedicinal herbaceous species that grows abundantly in tropical and sub-tropical regions of China, India, South-Eastern Asia and Africa. It is a popular nutraceutical that is employed in various forms of clinical and cosmetic treatments. C. asiatica extracts are reported widely in Ayurvedic and Chinese traditional medicine to boost memory, prevent cognitive deficits and improve brain functions. The major bioactive constituents of C. asiatica are the pentacyclic triterpenoid glycosides, asiaticoside and madecassoside, and their corresponding aglycones, asiatic acid and madecassic acid. Asiaticoside and madecassoside have been identified as the marker compounds of C. asiatica in the Chinese Pharmacopoeia and these triterpene compounds offer a wide range of pharmacological properties, including neuroprotective, cardioprotective, hepatoprotective, wound healing, anti-inflammatory, anti-oxidant, anti-allergic, anti-depressant, anxiolytic, antifibrotic, antibacterial, anti-arthritic, anti-tumour and immunomodulatory activities. Asiaticoside and madecassoside are also used extensively in treating skin abnormalities, burn injuries, ischaemia, ulcers, asthma, lupus, psoriasis and scleroderma. Besides medicinal applications, these phytocompounds are considered cosmetically beneficial for their role in anti-ageing, skin hydration, collagen synthesis, UV protection and curing scars. Existing reports and experimental studies on these compounds between 2005 and 2022 have been selectively reviewed in this article to provide a comprehensive overview of the numerous therapeutic advantages of asiaticoside and madecassoside and their potential roles in the medical future.

Terpenoid natural products exert neuroprotection via the PI3K/Akt pathway

PI3K/Akt, an essential signaling pathway widely present in cells, has been shown to be relevant to neurological disorders. As an important class of natural products, terpenoids exist in large numbers and have diverse backbones, so they have a great chance to be identified as neuroprotective agents. In this review, we described and summarized recent research for a range of terpenoid natural products associated with the PI3K/Akt pathway by classifying their basic chemical structures of the terpenes, identified by electronic searches on PubMed, Web of Science for research, and Google Scholar websites. Only articles published in English were included. Our discussion here concerned 16 natural terpenoids and their mechanisms of action, the associated diseases, and the methods of experimentation used. We also reviewed the discovery of their chemical structures and their derivatives, and some compounds have been concluded for their structure–activity relationships (SAR). As a result, terpenoids are excellent candidates for research as natural neuroprotective agents, and our content will provide a stepping stone for further research into these natural products. It may be possible for more terpenoids to serve as neuroprotective agents in the future.

Vitexin Glucolone Reinforces Radiosensitivity of Non-Small Cell Lung Cancer via Transforming Growth Factor Kinase 1/Adenylate Activated Protein Kinase Signaling Pathway

Purpose: To discuss effects of vitexin glucolone (VG) to radiosensitivity of NSCLC (Non-small cell lung cancer) cell lines (A549 and H1299). Methods: Treating A549 and H1299 cells by VG with or without X-radiation. Cell viability was calculated by CCK8. Apoptosis rate was measured by flow cytometry and Western blot to expressions of protein. Subsequently, cells were transferred with TAK1 siRNA, cell viability and apoptosis were measured. Results: VG decreased the viability of Huh7 cells and inhibited effects of VG was more strengthen than radiotherapy in concentrations of 20 μmol/L and 40 μmol/L. Meanwhile, VG sensitized HCC exposed to radiation therapy to apoptosis as demonstrated by increased Bax/Bcl-2 ratio. In addition, VG enhanced the promotive effects of X-radiation on the expressions of TAK1, AMPKα1 and PPARγ. Furthermore, silence the expression of TAK1 partly reversed the effects of VG on HCC and radiosensitivity of NSCLC. Conclusion: VG enhances radiosensitivity of NSCLC via TAK1/AMPK pathway.

Mitochondria-lysosome crosstalk in GBA1-associated Parkinson's disease

Organelle crosstalk is significant in regulating their respective functions and subsequent cell fate. Mitochondria and lysosomes are amongst the essential organelles in maintaining cellular homeostasis. Mitochondria-lysosome connections, which may develop dynamically in the human neurons, have been identified as sites of bidirectional communication. Aberrancies are often associated with neurodegenerative disorders like Parkinson's disease (PD), suggesting the physical and functional link between these two organelles. PD is often linked with genetic mutations of several mutations discovered in the familial forms of the disease; some are considered risk factors. Many of these genes are either associated with mitochondrial function or belong to endo-lysosomal pathways. The recent investigations have indicated that neurons with mutant glucosylceramidase beta (GBA1) exhibit extended mitochondria-lysosome connections in individuals with PD. This may be due to impaired control of the untethering protein, which aids in the hydrolysis of Rab7 GTP required for contact untethering. A GCase modulator may be used to augment the reduced GBA1 lysosomal enzyme activity in the neurons of PD patients. This review focuses on how GBA1 mutation in PD is interlinked with mitochondria-lysosome (ML) crosstalk, exploring the pathways governing these interactions and mechanistically comprehending the mitochondrial and lysosomal miscommunication in the pathophysiology of PD. This review is based on the limited literature available on the topic and hence may be subject to bias in its views. Our estimates may be conservative and limited due to the lack of studies under the said discipline due to its inherent complex nature. The current association of GBA1 to PD pathogenesis is based on the limited scope of study and further research is necessary to explore the risk factors further and identify the relationship with more detail.

Therapeutic Potential of Different Natural Products for the Treatment of Alzheimer’s Disease

A high incidence of dementia (60–80%) and a high rate of memory loss are two of the most common symptoms of Alzheimer's disease (AD), which affects the elderly. Researchers have recommended that traditional Chinese medicine (TCM) and Indian medicines can be used to prevent and cure AD. Several studies have linked neuroinflammation linked to amyloid-β (Aβ) deposition in the brain to the pathophysiology of neurodegenerative disorders. As a result, more research is needed to determine the role of inflammation in neurodegeneration. Increased microglial activation, cytokine production, reactive oxygen species (ROS), and nuclear factor kappa B (NF-κB) all play a role in the inflammatory process of AD. This review focuses on the role of neuroinflammation in neuroprotection and the molecular processes used by diverse natural substances, phytochemicals, and herbal formulations in distinct signaling pathways. Currently, researchers are focusing on pharmacologically active natural compounds with the anti-neuroinflammatory potential, making them a possible contender for treating AD. Furthermore, the researchers investigated the limits of past studies on TCM, Indian Ayurveda, and AD. Numerous studies have been carried out to examine the effects of medicinal whole-plant extracts on AD. Clinical investigations have shown that lignans, flavonoids, tannins, polyphenols, triterpenoids, sterols, and alkaloids have anti-inflammatory, antiamyloidogenic, anticholinesterase, and antioxidant properties. This review summarizes information about numerous medicinal plants and isolated compounds used in the treatment of AD and a list of further references.

Actions and Therapeutic Potential of Madecassoside and Other Major Constituents of Centella asiatica: A Review

Centella asiatica is a popular herb well-known for its wide range of therapeutic effects and its use as a folk medicine for many years. Its therapeutic properties have been well correlated with the presence of asiaticoside, madecassoside, asiatic and madecassic acids, the pentacyclic triterpenes. The herb has been extensively known to treat skin conditions; nevertheless, several pre-clinical and clinical studies have scientifically demonstrated its effectiveness in other disorders. Among the active constituents that have been identified in Centella asiatica, madecassoside has been the subject of only a relatively small number of scientific reports. Therefore, this review, while including other major constituents of this plant, focuses on the therapeutic potential, pharmacokinetics and toxicity of madecassoside.

Ethnobotany, Phytochemistry and Pharmacological Features of Centella asiatica: A Comprehensive Review

Centella asiatica (CA) or Gotu cola is an herbal plant from the Apiaceae family with a long history of usage in different traditional medicines. It has long been used for the treatment of various ailments such as central nervous system (CNS), skin and gastrointestinal disorders especially in the Southeast Asia. This chapter focused on the phytochemical constituent and pharmacological activities of CA based on preclinical and clinical studies. Additionally, botanical description and distribution, traditional uses, interactions, and safety issues are reviewed. Electronic databases of Google Scholar, Scopus, PubMed, and Web of Science were searched to obtain relevant studies on the pharmacological activities of CA. Approximately, 124 chemical compounds including triterpenoids, polyphenolic compounds, and essential oils have been isolated and identified from CA. Ethnomedicinal applications of CA mostly include treatment of gastrointestinal diseases, wounds, nervous system disorders, circulatory diseases, skin problems, respiratory ailments, diabetes and sleep disorders in various ethnobotanical practices. Pharmacological studies revealed a wide range of beneficial effects of CA on CNS, cardiovascular, lung, liver, kidney, gastrointestinal, skin, and endocrine system. Among them, neuroprotective activity, wound healing and treatment of venous insufficiency, as well as antidiabetic activity seem to be more frequently reported. At the moment, considering various health benefits of CA, it is marketed as an oral supplement as well as a topical ingredient in some cosmetic products. Additional preclinical studies and particularly randomized controlled trials are needed to clarify the therapeutic roles of CA.

Blood-Brain Barrier Permeability of Asiaticoside, Madecassoside and Asiatic Acid in Porcine Brain Endothelial Cell Model

Neurotherapeutic potentials of Centella asiatica and its reputation to boost memory, prevent cognitive deficits and improve brain functions are widely acknowledged. The plant's bioactive compounds, i.e. asiaticoside, madecassoside and asiatic acid were reported to have central nervous system (CNS) actions, particularly in protecting the brain against neurodegenerative disorders. Hence, it is important for these compounds to cross the blood-brain barrier (BBB) to be clinically effective therapeutics. This study aimed to explore the capability of asiaticoside, madecassoside and asiatic acid to cross the BBB using in vitro BBB model from primary porcine brain endothelial cells (PBECs). Our findings showed that asiaticoside, madecassoside and asiatic acid are highly BBB permeable with apparent permeability (P_app) of 70.61 ± 6.60, 53.31 ± 12.55 and 50.94 ± 10.91 × 10^-6 cm/s respectively. No evidence of cytotoxicity and tight junction disruption of the PBECs were observed in the presence of these compounds. Asiatic acid showed cytoprotective effect towards the PBECs against oxidative stress. This study reported for the first time that Centella asiatica compounds demonstrated high capability to cross the BBB, comparable to central nervous system drugs, and therefore warrant further development as therapeutics for the treatment of neurodegenerative diseases.

Neurotransmitter, Antioxidant and Anti-neuroinflammatory Mechanistic Potentials of Herbal Medicines in Ameliorating Autism Spectrum Disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental issue that disrupts behavior, nonverbal communication, and social interaction, impacting all aspects of an individual's social development. The underlying origin of autism is unclear, however, oxidative stress, as well as serotonergic, adrenergic and dopaminergic systems are thought to be implicated in ASD. Despite the fact that there is no effective medication for autism, current pharmacological treatments are utilized to ameliorate some of the symptoms such as selfmutilation, aggression, repetitive and stereotyped behaviors, inattention, hyperactivity, and sleep disorders.

METHODS

In accord with the literature regarding the activity of herbal medicines on neurotransmitter function, we aimed to review the most worthy medicinal herbs possessing neuroprotective effects.

RESULTS

Based on the outcome, medicinal herbs such as Zingiber officinale, Astragalus membranaceu, Ginkgo biloba, Centella asiatica and Acorus calamus, have antioxidant activity, which can influence neurotransmitter systems and are potentially neuroprotective.

CONCLUSION

Consequently, these herbs, in theory at least, appear to be suitable candidates within an overall management strategy for those on the autism spectrum.

Amelioration of Mitochondrial Quality Control and Proteostasis by Natural Compounds in Parkinson's Disease Models

Parkinson’s disease (PD) is a well-known age-related neurodegenerative disorder associated with longer lifespans and rapidly aging populations. The pathophysiological mechanism is a complex progress involving cellular damage such as mitochondrial dysfunction and protein homeostasis. Age-mediated degenerative neurological disorders can reduce the quality of life and also impose economic burdens. Currently, the common treatment is replacement with levodopa to address low dopamine levels; however, this does not halt the progression of PD and is associated with adverse effects, including dyskinesis. In addition, elderly patients can react negatively to treatment with synthetic neuroprotection agents. Recently, natural compounds such as phytochemicals with fewer side effects have been reported as candidate treatments of age-related neurodegenerative diseases. This review focuses on mitochondrial dysfunction, oxidative stress, hormesis, proteostasis, the ubiquitin‒proteasome system, and autophagy (mitophagy) to explain the neuroprotective effects of using natural products as a therapeutic strategy. We also summarize the efforts to use natural extracts to develop novel pharmacological candidates for treatment of age-related PD.

Nootropic and Anti-Alzheimer's Actions of Medicinal Plants: Molecular Insight into Therapeutic Potential to Alleviate Alzheimer's Neuropathology

Medicinal plants are the backbone of modern medicine. In recent times, there is a great urge to discover nootropic medicinal plants to reverse cognitive dysfunction owing to their less adverse effects. Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the inevitable loss of cognitive function, memory and language impairment, and behavioral disturbances, which turn into gradually more severe. Alzheimer's has no current cure, but symptomatic treatments are available and research continues. The number of patients suffering from AD continues to rise and today, there is a worldwide effort under study to find better ways to alleviate Alzheimer's pathogenesis. In this review, the nootropic and anti-Alzheimer's potentials of 6 medicinal plants (i.e., Centella asiatica, Clitoria ternatea, Crocus sativus, Terminalia chebula, Withania somnifera, and Asparagus racemosus) were explored through literature review. This appraisal focused on available information about neuroprotective and anti-Alzheimer's use of these plants and their respective bioactive compounds/metabolites and associated effects in animal models and consequences of its use in human as well as proposed molecular mechanisms. This review progresses our existing knowledge to reveal the promising linkage of traditional medicine to halt AD pathogenesis. This analysis also avowed a new insight to search the promising anti-Alzheimer's drugs.

Treadmill Exercise Improves Motor Function by Suppressing Purkinje Cell Loss in Parkinson Disease Rats

PURPOSE

Rotenone is the most widely used neurotoxin for the making Parkinson disease (PD) animal model. The neurodegenerative disorder PD shows symptoms, such as slowness of movements, tremor at resting, rigidity, disturbance of gait, and instability of posture. We investigated whether treadmill running improves motor ability using rotenone-caused PD rats. The effect of treadmill running on PD was also assessed in relation with apoptosis of cerebellar Purkinje cells.

METHODS

Treadmill running was applied to the rats in the exercise groups for 30 minutes once a day for 4 weeks, starting 4 weeks after birth. We used rota-rod test for the determination of motor coordination and balance. In this experiment, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, immunohistochemistry for calbindin, glial fibrillary acidic protein (GFAP), Iba-1, and western blot analysis for Bax and Bcl-2 were performed.

RESULTS

Treadmill running enhanced motor balance and coordination by preventing the loss of Purkinje cells in the cerebellar vermis. Treadmill running suppressed PD-induced expression of GFAP-positive reactive astrocytes and Iba-1-positive microglia, showing that treadmill running suppressed reactive astrogliosis and microglia activation. Treadmill running suppressed TUNEL-positive cell number and Bax expression and enhanced Bcl-2 expression, demonstrating that treadmill running inhibited the progress of apoptosis in the cerebellum of rotenone-induced PD rats.

CONCLUSION

Treadmill running improved motor ability of the rotenone-induced PD rats by inhibiting apoptosis in the cerebellum. Apoptosis suppressing effect of treadmill running on rotenone-induced PD was achieved via suppression of reactive astrocyte and inhibition of microglial activation.

Natural Molecules From Chinese Herbs Protecting Against Parkinson's Disease via Anti-oxidative Stress

Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease, affecting about 7–10 million patients worldwide. The major pathological features of PD include loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) of the midbrain and the presence of α-synuclein-enriched Lewy bodies. Although the mechanism underlying PD pathogenesis remains to be elucidated, oxidative stress induced by the overproduction of reactive oxygen species (ROS) is widely accepted to be a key pathogenic factors. ROS cause oxidative damage to proteins, lipids, and DNA, which subsequently lead to neurodegeneration. Great efforts have been made to slow or stop the progress of PD. Unfortunately there is no effective cure for PD till now. Compounds with good antioxidant activity represent the promising candidates for therapeutics of PD. Some natural molecules from Chinese herbs are found to have good antioxidant activity. Both in vitro and in vivo studies demonstrate that these natural molecules could mitigate the oxidative stress and rescue the neuronal cell death in PD models. In present review, we summarized the reported natural molecules that displayed protective effects in PD. We also addressed the possible signal pathway through which natural molecules achieved their antioxidative effects and mitigate PD phenotypes. Hopefully it will pave the way to better recognize and utilize Chinese herbs for the treatment of PD.

Neuroprotective effect of a standardized extract of Centella asiatica ECa233 in rotenone-induced parkinsonism rats

BACKGROUND

Mitochondrial dysfunction and reactive oxygen species (ROS) generation cause dopaminergic neurodegeneration in Parkinson's disease. The neuroprotective approach is a promising strategy to slow disease progression in Parkinson's disease. A standardized extract of Centella asiatica ECa233 has been previously reported to have pharmacological effects in the central nervous system.

PURPOSE

This study aimed to determine the neuroprotective effect and mechanisms of ECa233 in rotenone-induced parkinsonism rats.

METHODS

Rats were orally given either vehicle or ECa233 (10, 30 and 100 mg/kg) for 20 consecutive days. Rotenone (2.5 mg/kg i.p.) was given to parkinsonism (PD) and ECa-treated rats from day 15 to 20. Locomotor activity was recorded on day 1, 14, 17 and 20. Tyrosine-hydroxylase (TH) immunohistological staining was used to determine dopaminergic neurons in the substantia nigra and striatum. Furthermore, mitochondrial complex I activity, malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase protein expression were measured in brain tissue.

RESULTS

Rats receiving ECa233 30 mg/kg showed a significant increase in distances (p < 0.01) together with a higher number and intensity of dopaminergic neurons in the substantia nigra and striatum (p < 0.001) compared to PD rats. ECa233 (30 mg/kg) protected against mitochondrial complex I inhibition, decreased MDA levels (p < 0.05) and increased SOD (p < 0.01) and catalase (p < 0.05) expression.

CONCLUSION

ECa233 can protect against rotenone-induced motor deficits and dopaminergic neuronal death. These effects are mediated through the protection of mitochondrial complex I activity, the effects of antioxidants and the enhancement of antioxidant enzyme expression.

Behavioral and neurochemical consequences of perinatal exposure to lead in adult male Wistar rats: protective effect by Centella asiatica

The present study evaluated the protective effects of Centella asiatica (CA) leaf extract on behavioral deficits and neurotoxicity in adult rat exposed to lead during perinatal period. Adult Wistar rats were exposed to 0.15% lead acetate (Pb) from gestation day 6 through drinking water and the pups were exposed lactationally to Pb till weaning. Significant perturbations in locomotor activity and exploratory behavior were observed in rats exposed to Pb during perinatal period. The levels of lipid peroxidation increased significantly with a reduction in levels of glutathione and activity levels of acetylcholinesterase and antioxidant enzymes in hippocampus, cerebrum, cerebellum, and medulla of brains excised from Pb-exposed rats. Oral supplementation of CA during postweaning period provided significant protection against Pb-induced behavioral impairments and neurotoxicity, without chelating tissue Pb levels. The possible neuroprotective efficacy of CA may be due to its antioxidant potential but not by lowering effects of brain Pb content.

Effects of Centella asiatica (L.) Urb. on cognitive function and mood related outcomes: A Systematic Review and Meta-analysis

Centella asiatica (L.) Urb. has been used as an herbal brain tonic for mental disorders and enhancing memory, but no review of the overall evidence of C. asiatica and cognitive function has been conducted. This study aims to determine the effects of C. asiatica on cognitive function and its related properties. The current systematic review includes five randomized controlled trials (RCTs) conducted to determine the effect of C. asiatica alone and six RCTs conducted to determine the effect of C. asiatica-containing products. Meta-analysis indicated that there are no significant differences in all cognitive function domains of C. asiatica when compared to placebo. However, it could improve mood by increasing alert scores [SMD: 0.71 (95% CI; 0.01 to 1.41); I² = 30.5%] and decreasing anger scores at 1 hour after treatment [SMD: −0.81 (95%CI; −1.51 to −0.09); I² = 36.6%]. None of the studies reported adverse effects of C. asiatica. In conclusion, there is not strong evidence to support the use of C. asiatica for cognitive function improvement in each cognitive domain. C. asiatica could improve alertness and relieve anger. However, some limitations should be aware including dose regimen, plant preparation, standardization, and product variation. Future well-designed clinical trials using suitable doses of standardized C. asiatica are still needed.

Molecular cloning of an ester-forming triterpenoid: UDP-glucose 28-O-glucosyltransferase involved in saponin biosynthesis from the medicinal plant Centella asiatica

Triterpene saponins include bioactive compounds with structures consisting of triterpene aglycones (sapogenins) and one or more sugar moieties linked through acetal or ester glycosidic linkages at one or more sites. Centella asiatica (L.) Urban is a medicinal plant that contains bioactive ursane-type saponins, such as madecassoside and asiaticoside. In this work, glucosylation of triterpenoids in C. asiatica was investigated starting with plant extracts. An enzyme capable of glucosylating asiatic and madecassic acids was partially purified. Proteomics methods and cDNA sequence data were employed as tools to obtain a full-length cDNA clone encoding a glucosyltransferase. The recombinant gene product, UGT73AD1, was functionally expressed in Escherichia coli and purified by immobilized metal-affinity chromatography. Purified recombinant UGT73AD1 was found to have a narrow specificity, glucosylating asiatic and madecassic acids at the C28 carboxyl. mRNA accumulated in all tissues tested (leaves, stems, roots and flowers), with highest expression in leaves. Thus, UGT73AD1 was identified as a triterpenoid carboxylic acid: UDP-glucose 28-O-glucosyltransferase that appears to be involved in saponin biosynthesis in C. asiatica.

Complete Comparison Display (CCD) evaluation of ethanol extracts of Centella asiatica and Withania somnifera shows that they can non-synergistically ameliorate biochemical and behavioural damages in MPTP induced Parkinson's model of mice

Parkinson's disease remains as one of the most common debilitating neurodegenerative disorders. With the hopes of finding agents that can cure or reduce the pace of progression of the disease, we studied two traditional medicinal plants: Centella asiatica and Withania somnifera that have been explored in some recent studies. In agreement with the previous work on ethanol extracts of these two plants in mice model, we saw an improvement in oxidative stress profile as well as behavioral performance in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced Parkinson-like symptoms in Balb/c mice. Given the known potential of both the herbal extracts in improving Parkinson-like symptoms, we expected the combination of the two to show better results than either of the two but surprisingly there was no additivity in either oxidative stress or behavioural recovery. In fact, in some assays, the combination performed worse than either of the two individual constituents. This effect of mixtures highlights the need of testing mixtures in supplements market using enthomedicine. The necessity of comparing multiple groups in this study to get most information from the experiments motivated us to design a ladder-like visualization to show comparison with different groups that we call complete comparison display (CCD). In summary, we show the potential of Centella asiatica and Withania somnifera to ameliorate Parkinson's disorder.

Retracted Article: Vitexin mitigates myocardial ischemia reperfusion-induced damage by inhibiting excessive autophagy to suppress apoptosis via the PI3K/Akt/mTOR signaling cascade

Myocardial ischemia reperfusion (MI/R) injury is reported to induce apoptosis and autophagy of myocardial cells and contribute to adverse cardiovascular outcomes.

Asiaticoside ameliorates β-amyloid-induced learning and memory deficits in rats by inhibiting mitochondrial apoptosis and reducing inflammatory factors

The present study aimed to investigate the effects of asiaticoside (AS) on the pathology and associated mechanisms of β-amyloid (Aβ)-induced Alzheimer's disease (AD) in rats. An AD rat model was established by lateral intracerebroventricular injection of Aβ 1–42 oligomers. Learning and memory function were evaluated by Morris water maze (MWM) test. In addition, hematoxylin and eosin (H&E) staining, transmission electron microscopy (TEM), immunohistochemistry, ELISA and western blot analysis were performed to evaluate the disease pathogenesis. The results indicated that AS exerted protective effects in rats treated with Aβ oligomers, in a dose-dependent manner, as evidenced by the improved learning and memory function in the MWM test. In addition, H&E staining of hippocampal tissue showed that the histological structure was damaged in the model group, which was restored by AS treatment. Aβ deposition was dramatically increased in the model group, and the pathological changes were reversed by AS treatment. TEM revealed that the subcellular structure was injured by Aβ oligomers, however, the structure was ameliorated by AS treatment. Furthermore, AS was found to reduce the elevated levels of pro-inflammatory cytokines, interleukin-6 and tumor necrosis factor-α, in the brains of Aβ-treated rats. In addition, AS treatment resulted in a significant decrease in the expression of caspases-3, whereas the expression of B-cell lymphoma-2 was significantly increased, in these Aβ-treated rats. According to the findings of the observed study, AS has a marked protective effect on Aβ-induced AD pathology, and the underlying mechanism may be associated with the alleviation of the mitochondrial injuries, the anti-inflammatory activities, and the influence on the expression levels of apoptosis-associated proteins.

Vitexin suppresses autophagy to induce apoptosis in hepatocellular carcinoma via activation of the JNK signaling pathway

Vitexin, a flavonoids compound, is known to exhibit broad anti-oxidative, anti-inflammatory, analgesic, and antitumor activity in many cancer xenograft models and cell lines. The purpose of this study was to investigate the antitumor effects and underlying mechanisms of vitexin on hepatocellular carcinoma. In this study, we found that vitexin suppressed the viability of HCC cell lines (SK-Hep1 and Hepa1-6 cells) significantly. Vitexin showed cytotoxic effects against HCC cell lines in vitro by inducing apoptosis and inhibiting autophagy. Vitexin induced apoptosis in a concentration-dependent manner, and caused up-regulations of Caspase-3, Cleave Caspase-3, and a down-regulation of Bcl-2. The expression of autophagy-related protein LC3 II was significantly decreased after vitexin treatment. Moreover, western blot analysis presented that vitexin markedly up-regulated the levels of p-JNK and down-regulated the levels of p-Erk1/2 in SK-Hep1 cells and Hepa1-6 cells. Cotreatment with JNK inhibitor SP600125, we demonstrated that apoptosis induced by vitexin was suppressed, while the inhibition of autophagy by vitexin was reversed. The results of colony formation assay and mouse model confirmed the growth inhibition role of vitexin on HCC in vitro and in vivo. In conclusion, vitexin inhibits HCC growth by way of apoptosis induction and autophagy suppression, both of which are through JNK MAPK pathway. Therefore, vitexin could be regarded as a potent therapeutic agent for the treatment of HCC.

Recent Updates in Neuroprotective and Neuroregenerative Potential of Centella asiatica

Centella asiatica, locally well known in Malaysia as pegaga, is a traditional herb that has been used widely in Ayurvedic medicine, traditional Chinese medicine, and in the traditional medicine of other Southeast Asian countries including Malaysia. Although consumption of the plant is indicated for various illnesses, its potential neuroprotective properties have been well studied and documented. In addition to past studies, recent studies also discovered and/or reconfirmed that C. asiatica acts as an antioxidant, reducing the effect of oxidative stress in vitro and in vivo. At the in vitro level, C. asiatica promotes dendrite arborisation and elongation, and also protects the neurons from apoptosis. In vivo studies have shown that the whole extract and also individual compounds of C. asiatica have a protective effect against various neurological diseases. Most of the in vivo studies on neuroprotective effects have focused on Alzheimer's disease, Parkinson's disease, learning and memory enhancement, neurotoxicity and other mental illnesses such as depression and anxiety, and epilepsy. Recent studies have embarked on finding the molecular mechanism of neuroprotection by C. asiatica extract. However, the capability of C. asiatica in enhancing neuroregeneration has not been studied much and is limited to the regeneration of crushed sciatic nerves and protection from neuronal injury in hypoxia conditions. More studies are still needed to identify the compounds and the mechanism of action of C. asiatica that are particularly involved in neuroprotection and neuroregeneration. Furthermore, the extraction method, biochemical profile and dosage information of the C. asiatica extract need to be standardised to enhance the economic value of this traditional herb and to accelerate the entry of C. asiatica extracts into modern medicine.

Asiaticoside attenuates diabetes-induced cognition deficits by regulating PI3K/Akt/NF-κB pathway

Diabetes-associated cognitive dysfunction, referred as "diabetic encephalopathy", has been confirmed in a great deal of literature. Current evidence support that oxidative stress, inflammation, energy metabolism imbalance, and aberrant insulin signaling are associated with cognition deficits induced by diabetes. The present study explore the effect of asiaticoside on the cognition behaviors, synapses, and oxidative stress in diabetic rats. Asiaticoside could markedly ameliorate the performance in the Morris Water Maze (decreased latency time and path length, and increased time spent in the target quadrant), which was correlated with its capabilities of suppressing oxidative stress, restoring Na(+)-K(+)-ATPase activity and protecting hippocampal synapses. In vitro, asiaticoside could up-regulate synaptic proteins expression via modulating Phosphoinositide 3-kinase (PI3K)/Protein Kinase B(AKT)/Nuclear Factor -kappa B (NF-κB)-mediated inflammatory pathway in SH-SY5Y cells incubated with high glucose chronically. In conclusion, asiaticoside had beneficial effects on the prevention and treatment of diabetes-associated cognitive deficits, which was involved in oxidative stress, PI3K/Akt/NF-κB pathway and synaptic function in the development of cognitive decline induced by diabetes.

Centella asiatica and Its Fractions Reduces Lipid Peroxidation Induced by Quinolinic Acid and Sodium Nitroprusside in Rat Brain Regions

Oxidative stress has been implicated in several pathologies including neurological disorders. Centella asiatica is a popular medicinal plant which has long been used to treat neurological disturbances in Ayurvedic medicine. In the present study, we quantified of compounds by high performance liquid chromatography (HPLC) and examined the phenolic content of infusion, ethyl acetate, n-butanolic and dichloromethane fractions. Furthermore, we analyzed the ability of the extracts from C. asiatica to scavenge the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) radical as well as total antioxidant activity through the reduction of molybdenum (VI) (Mo(6+)) to molybdenum (V) (Mo(5+)). Finally, we examined the antioxidant effect of extracts against oxidant agents, quinolinic acid (QA) and sodium nitroprusside (SNP), on homogenates of different brain regions (cerebral cortex, striatum and hippocampus). The HPLC analysis revealed that flavonoids, triterpene glycoside, tannins, phenolic acids were present in the extracts of C. asiatica and also the phenolic content assay demonstrated that ethyl acetate fraction is rich in these compounds. Besides, the ethyl acetate fraction presented the highest antioxidant effect by decreasing the lipid peroxidation in brain regions induced by QA. On the other hand, when the pro-oxidant agent was SNP, the potency of infusion, ethyl acetate and dichloromethane fractions was equivalent. Ethyl acetate fraction from C. asiatica also protected against thiol oxidation induced by SNP and QA. Thus, the therapeutic potential of C. asiatica in neurological diseases could be associated to its antioxidant activity.

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.

Neuroprotection by saponins

Saponins, an important group of bioactive plant natural products, are glycosides of triterpenoid or steroidal aglycones. Their diverse biological activities are ascribed to their different structures. Saponins have long been recognized as key ingredients in traditional Chinese medicine. Accumulated evidence suggests that saponins have significant neuroprotective effects on attenuation of central nervous system disorders, such as stroke, Alzheimer's disease, Parkinson's disease, and Huntington's disease. However, our understanding of the mechanisms underlying the observed effects remains incomplete. Based on recently reported data from basic and clinical studies, this review highlights the proposed mechanisms of their neuroprotective function including antioxidant, modulation of neurotransmitters, anti-apoptosis, anti-inflammation, attenuating Ca(2+) influx, modulating neurotrophic factors, inhibiting tau phosphorylation, and regeneration of neural networks.

Neuroprotective effects of Asiaticoside

In the central nervous system, Asiaticoside has been shown to attenuate in vitro neuronal damage caused by exposure to β-amyloid. In vivo studies demonstrated that Asiaticoside could attenuate neurobehavioral, neurochemical and histological changes in transient focal middle cerebral artery occlusion animals. In addition, Asiaticoside showed anxiolytic effects in acute and chronic stress animals. However, its potential neuroprotective properties in glutamate-induced excitotoxicity have not been fully studied. We investigated the neuroprotective effects of Asiaticoside in primary cultured mouse cortical neurons exposed to glutamate-induced excitotoxicity invoked by N-methyl-D-aspartate. Pretreatment with Asiaticoside decreased neuronal cell loss in a concentration-dependent manner and restored changes in expression of apoptotic-related proteins Bcl-2 and Bax. Asiaticoside pretreatment also attenuated the upregulation of NR2B expression, a subunit of N-methyl-D-aspartate receptors, but did not affect expression of NR2A subunits. Additionally, in cultured neurons, Asiaticoside significantly inhibited Ca²⁺ influx induced by N-methyl-D-aspartate. These experimental findings provide preliminary evidence that during excitotoxicity induced by N-methyl-D-aspartate exposure in cultured cortical neurons, the neuroprotective effects of Asiaticoside are mediated through inhibition of calcium influx. Aside from its anti-oxidant activity, down-regulation of NR2B-containing N-methyl-D-aspartate receptors may be one of the underlying mechanisms in Asiaticoside neuroprotection.

Nepalese traditional medicine and symptoms related to Parkinson's disease and other disorders: Patterns of the usage of plant resources along the Himalayan altitudinal range

ETHNOPHARMACOLOGICAL RELEVANCE

Nepal is a hotspot for cultural and biological diversities. The tremendous diversity of ecosystems and climates and the blend of medicinal practices inherited from Ayurvedic and Traditional Tibetan Medicine are well suited to a study aimed at discovering information about medicinal plants to treat Parkinson's disease (PD). In addition, this study across Nepal's altitudinal range is relevant to understanding how cultural and ecological environments influence local traditional medicines. The aim of the study is to document the uses of medicinal plants in three different eco-geographical areas of Nepal (Chitwan-Panchase-Mustang) to treat symptoms related to PD. A second goal is to analyze the impact of culture and environment on the evolution of traditional medicine.

MATERIALS AND METHODS

The study was conducted in five communities located in three different eco-geographical environments and at altitudes ranging from 300m to 3700m. We interviewed a total of 56 participants (local people, folk, Ayurvedic and Amchi healers) across the three research areas. We conducted open-ended interviews to document the uses of medicinal plants to treat PD-related symptoms. Information provided by the interviewees suggested that the medicinal plants are also used to treat symptoms related to other disorders. We determined the informant consensus factor as well as the importance of specific plant species to (i) identify plants that are the best candidates to be analyzed experimentally for their potential to treat PD and (ii) perform a cross-cultural comparison of the three areas of study.

RESULTS

This study reports the local uses of 35 different plant species along the Chitwan-Panchase-Mustang altitudinal range. We identify a total of eight plant species that were used in all three research areas, and more specifically one species used to treat PD-like symptoms. We identify a potential dual protective activity of medicinal plants used to treat PD-related symptoms as recent literature suggests that these plants also have anti-cancer properties. In addition, we document that the presence of Ayurvedic healers could influence local practices and that local practices could influence local Ayurvedic practices.

CONCLUSIONS

This study documents the uses of medicinal plants to treat symptoms related to PD and other disorders across the Chitwan-Panchase-Mustang altitudinal range. PD is a neurodegenerative disease affecting a growing number of people worldwide. No cures are available to slow the death of the neurons, and there is a critical need to work towards innovative therapeutic strategies. We identify medicinal plants based on traditional practices to help develop a cure for PD. The three areas of study were chosen for their ecological and cultural diversities, and two of these are included in conservation programs (Panchase Protected Forest and Annapurna Conservation Area). The documentation of community-natural resource relationships is another step in the preservation of traditional practices and local biodiversity and a reflection of communities' rights in the design of conservation programs.

Acute morphine treatments alleviate tremor in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated monkeys

Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disorder associated with decreased striatal dopamine levels. Morphine has been found to elevate dopamine levels, which indicates a potential therapeutic effect in PD treatment that has not been investigated previously. To evaluate this hypothesis, an investigation of the acute effects of morphine on PD symptoms was carried out in male rhesus PD monkeys that had been induced with MPTP. All MPTP induced monkeys displayed progressive and irreversible PD motor symptoms. The behavioral response of these animals to morphine and L-Dopa were quantified with the Kurlan scale. It was found that L-Dopa alleviated bradykinesia, but did not significantly improve tremor. In contrast, acute morphine alleviated tremor significantly. These results suggested that, compared to L-Dopa, morphine has different therapeutic effects in PD therapy and may act through different biological mechanisms to alleviate PD symptoms.

Advances in neuroprotective ingredients of medicinal herbs by using cellular and animal models of Parkinson's disease

Parkinson's disease (PD) is a multifactorial disorder, which is neuropathologically identified by age-dependent neurodegeneration of dopaminergic neurons in the substantia nigra. Development of symptomatic treatments has been partly successful for PD research, but there remain a number of inadequacies in therapeutic strategies for the disease. The pathogenesis of PD remains intricate, and the present anti-PD treatments appears to be clinically insufficient. Comprehensive research on discovery of novel drug candidates has demonstrated that natural products, such as medicinal herbs, plant extracts, and their secondary metabolites, have great potential as therapeutics with neuroprotective activity in PD. Recent preclinical studies suggest that a number of herbal medicines and their bioactive ingredients can be developed into optimum pharmaceuticals for treating PD. In many countries, traditional herbal medicines are used to prevent or treat neurodegenerative disorders, and some have been developed as nutraceuticals or functional foods. Here we focus on recent advances of the evidence-linked neuroprotective activity of bioactive ingredients of herbal origin in cellular and animal models of PD research.

Beneficial effects of asiaticoside on cognitive deficits in senescence-accelerated mice

The effect of asiaticoside isolated from Hydrocotyle sibthorpioides (AHS) on the promotion of cognition in senescence-accelerated mice (SAMP) was evaluated. Six-month old male SAMP8 mice were orally administered 20, 40 or 80 mg/kg AHS daily for three months. SAMR1 mice were used as a "normal aging" control. The results showed that treatment with AHS significantly improved learning and memory abilities in behavioral tests. AHS-treated mice showed higher antioxidant enzyme activity and lower lipid oxidation in serum compared with untreated SAMP8 mice. Mechanistically, studies showed that AHS markedly reduced the content and deposition of β-amyloid peptide (Aβ) by inhibiting the expression of mRNA for amyloid protein precursor, β-site amyloid cleaving enzyme-1 and cathepsin B and promoting the expression of mRNA for neprilysin and insulin degrading enzyme. In addition, AHS significantly increased the expression of plasticity-related proteins including postsynaptic density-95, phosphor-N-methyl-D-aspartate receptor 1, phospho-calcium-calmodulin dependent kinase II, phospho-protein kinase A Catalyticβ subunit, protein kinase Cγ subunit, phospho-CREB and brain derived neurotrophic factor. Furthermore, AHS increased the levels of acetylcholine (Ach), but decreased cholinesterase (AchE) activity. These results demonstrated that AHS administration may prevent spatial learning and memory decline by scavenging free radicals, up-regulating the activity of antioxidant enzymes, decreasing the level of Aβ, ameliorating dysfunction in synaptic plasticity, and reversing abnormal changes in Ach level and AchE activity. Thus, AHS should be developed as a new drug to prevent age-related cognitive deficits.

Centella asiatica attenuates the neurobehavioral, neurochemical and histological changes in transient focal middle cerebral artery occlusion rats

Centella asiatica has been used as psychoactive and antioxidant herbal medicine since ancient time. The present study was design to evaluate the preventive role of ethanolic extract of C. asiatica in middle cerebral artery occlusion (MCAO) in rats. Male Wistar rats were gavaged orally with C. asiatica extract (100, 200 and 300 mg/kg body weight once daily) for 21 days and thereafter subjected to right MCAO for 2 h followed by 22-h reperfusion. Brain injury was evaluated by 2,3,5-triphenyltetrazolium chloride and hematoxylin and eosin staining. Behavioural outcomes as neurological deficit, rota rod test, and grip strength were assessed. In addition, lipid peroxidation, enzymatic and non enzymatic antioxidants were analyzed to assess the oxidative stress. Our results revealed that C. asiatica administration greatly improved neurobehavioral activity and diminished infarction volume along with the restored histological morphology of brain in MCAO rats. Furthermore, supplementation with this extract to MCAO group has reduced the level of thiobarbituric acid reactive species, restored glutathione content and augmented the activities of antioxidant enzymes-catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and superoxide dismutase in a dose-dependent manner in ischemic rats. The remarkable antioxidant activity of C. asiatica may be attributed to its bioactive triterpenes, asiatic acid, asiaticoside, madecassic acid and madecosside and may be translated to clinical level for prevention of ischemic stroke.

Centella asiatica (L.) Urban: From Traditional Medicine to Modern Medicine with Neuroprotective Potential

This paper covers the studies relevant to neuroprotective activity of Centella asiatica (L.) Urban, also known as “Gotu Kola.” The plant is native to the Southeast Asia and has been used traditionally as brain tonic in ayurvedic medicine. The neuroprotective effect of C. asiatica has been searched using the key words “Centella, Centella asiatica, gotu kola, Asiatic pennywort, neuroprotection, and memory” through the electronic databases including Sciencedirect, Web of Science, Scopus, Pubmed, and Google Scholar. According to the literature survey, C. asiatica (gotu kola) has been reported to have a comprehensive neuroprotection by different modes of action such as enzyme inhibition, prevention of amyloid plaque formation in Alzheimer's disease, dopamine neurotoxicity in Parkinson's disease, and decreasing oxidative stress. Therefore, C. asiatica could be suggested to be a desired phytopharmaceutical with neuroprotective effect emerged from traditional medicine.