Inhibition of Morphine- and Ethanol-Mediated Stimulation of Mesolimbic Dopamine Neurons by Withania somnifera

Binge-like administration of alcohol mixed to energy drinks to male adolescent rats severely impacts on mesocortical dopaminergic function in adulthood: A behavioral, neurochemical and electrophysiological study

A growing body of evidence indicates that the practice of consuming alcohol mixed with energy drinks (ED) (AMED) in a binge drinking pattern is significantly diffusing among the adolescent population. This behavior, aimed at increasing the intake of alcohol, raises serious concerns about its long-term effects. Epidemiological studies suggest that AMED consumption might increase vulnerability to alcohol abuse and have a gating effect on the use of illicit drugs. The medial prefrontal cortex (mPFC) is involved in the modulation of the reinforcing effects of alcohol and of impulsive behavior and plays a key role in the development of addiction. In our study, we used a binge-like protocol of administration of alcohol, ED, or AMED in male adolescent rats, to mimic the binge-like intake behavior observed in humans, in order to evaluate whether these treatments could differentially affect the function of mesocortical dopaminergic neurons in adulthood. We did so by measuring: i) physiological sensorimotor gating; ii) voluntary alcohol consumption and dopamine transmission before, during, and after presentation of alcohol; iii) electrophysiological activity of VTA dopaminergic neurons and their sensitivity to a challenge with alcohol. Our results indicate that exposure to alcohol, ED, or AMED during adolescence induces differential adaptive changes in the function of mesocortical dopaminergic neurons and, in particular, that AMED exposure decreases their sensitivity to external stimuli, possibly laying the foundation for the altered behaviors observed in adulthood.

Bi-directional modulation of hyperpolarization-activated cation currents (Ih) by ethanol in rat hippocampal CA3 pyramidal neurons

It is widely acknowledged that ethanol (EtOH) can alter many neuronal functions, including synaptic signaling, firing discharge, and membrane excitability, through its interaction with multiple membrane proteins and intracellular pathways. Previous work has demonstrated that EtOH enhances the firing rate of hippocampal GABAergic interneurons and thus the presynaptic GABA release at CA1 and CA3 inhibitory synapses through a positive modulation of the hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels. Activation of HCN channels produce an inward current, commonly called I_h, which plays an essential role in generating/regulating specific neuronal activities in GABAergic interneurons and principal glutamatergic pyramidal neurons such as those in the CA3 subregion. Since the direct effect of EtOH on HCN channels expressed in CA3 pyramidal neurons was not thoroughly elucidated, we investigated the possible interaction between EtOH and HCN channels and the impact on excitability and postsynaptic integration of these neurons. Patch-clamp recordings were performed in single CA3 pyramidal neurons from acute male rat coronal hippocampal slices. Our results show that EtOH modulates HCN-mediated I_h in a concentration-dependent and bi-directional manner, with a positive modulation at lower (20 mM) and an inhibitory action at higher (60-80 mM) concentrations. The modulation of I_h by EtOH was mimicked by forskolin, antagonized by different drugs that selectively interfere with the AC/cAMP/PKA intracellular pathway, as well as by the selective HCN inhibitor ZD7288. Altogether, these data further support the evidence that HCN channels may represent an important molecular target through which EtOH may regulate neuronal activity.

Cross-talk between the HPA axis and addiction-related regions in stressful situations

Addiction is a worldwide problem that has a negative impact on society by imposing significant costs on health care, public security, and the deactivation of the community economic cycle. Stress is an important risk factor in the development of addiction and relapse vulnerability. Here we review studies that have demonstrated the diverse roles of stress in addiction. Term searches were conducted manually in important reference journals as well as in the Google Scholar and PubMed databases, between 2010 and 2022. In each section of this narrative review, an effort has been made to use pertinent sources. First, we will provide an overview of changes in the Hypothalamus-Pituitary-Adrenal (HPA) axis component following stress, which impact reward-related regions including the ventral tegmental area (VTA) and nucleus accumbens (NAc). Then we will focus on internal factors altered by stress and their effects on drug addiction vulnerability. We conclude that alterations in neuro-inflammatory, neurotrophic, and neurotransmitter factors following stress pathways can impact related mechanisms on craving and relapse susceptibility.

Withania somnifera influences MDMA-induced hyperthermic, cognitive, neurotoxic and neuroinflammatory effects in mice

Withania somnifera (WS) is utilized in Ayurvedic medicine owing to its central and peripheral beneficial properties. Several studies have accrued indicating that the recreational amphetamine-related drug (+/-)- 3,4-methylenedioxymethamphetamine (MDMA; Ecstasy) targets the nigrostriatal dopaminergic system in mice, inducing neurodegeneration and gliosis, causing acute hyperthermia and cognitive impairment. This study aimed to investigate the effect of a standardized extract of W. somnifera (WSE) on MDMA-induced neurotoxicity, neuroinflammation, memory impairment and hyperthermia. Mice received a 3-day pretreatment with vehicle or WSE. Thereafter, vehicle- and WSE-pretreated mice were randomly divided into four groups: saline, WSE, MDMA alone, WSE plus MDMA. Body temperature was recorded throughout treatment, and memory performance was assessed by a novel object recognition (NOR) task at the end of treatment. Thereafter, immunohistochemistry was performed to evaluate in the substantia nigra pars compacta (SNc) and striatum the levels of tyrosine hydroxylase (TH), as marker of dopaminergic degeneration, and of glial fibrillary acidic protein (GFAP) and TMEM119, as markers of astrogliosis or microgliosis, respectively. MDMA-treated mice showed a decrease in TH-positive neurons and fibers in the SNc and striatum respectively, an increase in gliosis and body temperature, and a decrease in NOR performance, irrespective of vehicle or WSE pretreatment. Acute WSE plus MDMA counteracted the modifications in TH-positive cells in SNc, GFAP-positive cells in striatum, TMEM in both areas and NOR performance, as compared to MDMA alone, while no differences were observed as compared to saline. Results indicate that WSE acutely administered in combination with MDMA, but not as pretreatment, protects mice against the noxious central effects of MDMA.

Effects of the Phenethylamine 2-Cl-4,5-MDMA and the Synthetic Cathinone 3,4-MDPHP in Adolescent Rats: Focus on Sex Differences

The illicit drug market of novel psychoactive substances (NPSs) is expanding, becoming an alarming threat due to increasing intoxication cases and insufficient (if any) knowledge of their effects. Phenethylamine 2-chloro-4,5-methylenedioxymethamphetamine (2-Cl-4,5-MDMA) and synthetic cathinone 3,4-methylenedioxy-α-pyrrolidinohexanophenone (3,4-MDPHP) are new, emerging NPSs suggested to be particularly dangerous. This study verified whether these two new drugs (i) possess abuse liability, (ii) alter plasma corticosterone levels, and (iii) interfere with dopaminergic transmission; male and female adolescent rats were included to evaluate potential sex differences in the drug-induced effects. Findings show that the two NPSs are not able to sustain reliable self-administration behavior in rats, with cumulatively earned injections of drugs being not significantly different from cumulatively earned injections of saline in control groups. Yet, at the end of the self-administration training, females (but not males) exhibited higher plasma corticosterone levels after chronic exposure to low levels of 3,4-MDPHP (but not of 2-Cl-4,5-MDMA). Finally, electrophysiological patch-clamp recordings in the rostral ventral tegmental area (rVTA) showed that both drugs are able to increase the firing rate of rVTA dopaminergic neurons in males but not in females, confirming the sex dimorphic effects of these two NPSs. Altogether, this study demonstrates that 3,4-MDPHP and 2-Cl-4,5-MDMA are unlikely to induce dependence in occasional users but can induce other effects at both central and peripheral levels that may significantly differ between males and females.

Potential clinical applications of Ashwagandha (Withania somnifera) in medicine and neuropsychiatry

INTRODUCTION

Ashwagandha (ASW) is the extract of the plant Withania somnifera. It is widely used in complementary, alternative, and integrative medicine (CAIM) but is little discussed in mainstream modern medical literature.

AREAS COVERED

We performed a review of potential pharmacotherapeutic properties of ASW. Studies were sourced from relevant online and offline databases. In animal models, ASW displays antioxidant activity. It has GABAergic and other neurotransmitter modulatory effects. It reduces apoptosis and promotes synaptic plasticity. It improves cognition and reverses induced cognitive deficits. It attenuates indices of stress. In human subjects, ASW enhances adaptogenesis in healthy adults. It modestly benefits generalized anxiety disorder and obsessive-compulsive disorder, and symptom severity in schizophrenia, substance use disorders, and attention deficit hyperactivity disorder. It improves sleep quality.

EXPERT OPINION

ASW may confer modest benefit in certain neuropsychiatric conditions. Its benefits may arise from induction of neuroplasticity, antioxidant and anti-inflammatory effects, and modulation of GABA and glutamate, as well as other neurotransmitters. The antioxidant and anti-inflammatory actions may also benefit neurodegenerative states. Reports of clinical benefit with ASW must be interpreted with caution, given the paucity of randomized clinical trials (RCTs). Greater methodological rigor is necessary before clinical recommendations on ASW can be confidently made.

Effects of docosanyl ferulate, a constituent of Withania somnifera, on ethanol- and morphine-elicited conditioned place preference and ERK phosphorylation in the accumbens shell of CD1 mice

BACKGROUND

Docosanyl ferulate (DF) is a behaviourally active GABA_A receptor complex (GABA_AR) agonist, recently isolated from the standardized methanolic extract of Withania somnifera Dunal (WSE) root. Previous studies have shown that WSE prevents both ethanol- and morphine-dependent acquisition and expression of conditioned place preference (CPP) and stimulation of dopamine release in the nucleus accumbens shell (AcbSh).

AIMS

The study aimed at determining (a) whether DF contributes to WSE's ability to affect the acquisition and expression of ethanol- and morphine-elicited CPP and, given that phosphorylation of extracellular signal-regulated kinase (pERK) in the AcbSh is involved in associative learning and motivated behaviours, (b) whether WSE and DF may affect ethanol- and morphine-induced ERKs phosphorylation in the AcbSh.

METHODS

In adult male CD1 mice, DF's effects on the acquisition and expression of ethanol- and morphine-elicited CPP were evaluated by a classical place conditioning paradigm, whereas the effects of WSE and DF on ethanol- and morphine-elicited pERK in the AcbSh were evaluated by immunohistochemistry.

RESULTS AND CONCLUSIONS

The study shows that DF, differently from WSE, affects only the acquisition but not the expression of ethanol- and morphine-induced CPP. Moreover, the study shows that both WSE and DF can prevent ethanol- and morphine-elicited pERK expression in the AcbSh. Overall, these results highlight subtle but critical differences for the role of GABA_ARs in the mechanism by which WSE affects these ethanol- and morphine-dependent behavioural and molecular/cellular responses and support the suggestion of WSE and DF for the control of different components of drug addiction.

Withania somnifera (L.) Dunal (Ashwagandha): A comprehensive review on ethnopharmacology, pharmacotherapeutics, biomedicinal and toxicological aspects

Withania somnifera (L.) Dunal (Solanaceae) has been used as a traditional Rasayana herb for a long time. Traditional uses of this plant indicate its ameliorative properties against a plethora of human medical conditions, viz. hypertension, stress, diabetes, asthma, cancer etc. This review presents a comprehensive summary of the geographical distribution, traditional use, phytochemistry, and pharmacological activities of W. somnifera and its active constituents. In addition, it presents a detailed account of its presence as an active constituent in many commercial preparations with curative properties and health benefits. Clinical studies and toxicological considerations of its extracts and constituents are also elucidated. Comparative analysis of relevant in-vitro, in-vivo, and clinical investigations indicated potent bioactivity of W. somnifera extracts and phytochemicals as anti-cancer, anti-inflammatory, apoptotic, immunomodulatory, antimicrobial, anti-diabetic, hepatoprotective, hypoglycaemic, hypolipidemic, cardio-protective and spermatogenic agents. W. somnifera was found to be especially active against many neurological and psychological conditions like Parkinson's disease, Alzheimer's disease, Huntington's disease, ischemic stroke, sleep deprivation, amyotrophic lateral sclerosis, attention deficit hyperactivity disorder, bipolar disorder, anxiety, depression, schizophrenia and obsessive-compulsive disorder. The probable mechanism of action that imparts the pharmacological potential has also been explored. However, in-depth studies are needed on the clinical use of W. somnifera against human diseases. Besides, detailed toxicological analysis is also to be performed for its safe and efficacious use in preclinical and clinical studies and as a health-promoting herb.

The biologically active compound of Withania somnifera (L.) Dunal, docosanyl ferulate, is endowed with potent anxiolytic properties but devoid of typical benzodiazepine-like side effects

BACKGROUND

Clinical and experimental studies support the therapeutic potential of Withania somnifera (WS) (L.) Dunal on anxiety disorders. This potential is attributable to components present in different plant extracts; however, the individual compound(s) endowed with specific anxiolytic effects and potential modulatory activity of the GABAA receptor complex (GABAAR) have remained unidentified until the recent isolation from a WS methanolic root extract of some GABAAR-active compounds, including the long alkyl-chain ferulic acid ester, docosanyl ferulate (DF).

AIMS

This study was designed to assess whether DF (0.05, 0.25 and 2 mg/kg), similarly to diazepam (2 mg/kg), may exert anxiolytic effects, whether these effects may be significantly blocked by the benzodiazepine antagonist flumazenil (10 mg/kg) and whether DF may lack some of the benzodiazepines' typical motor, cognitive and motivational side effects.

METHODS

The behavioural paradigms Elevated Plus Maze, Static Rods, Novel Object Recognition, Place Conditioning and potentiation of ethanol-induced Loss of Righting Reflex were applied on male CD-1 mice.

RESULTS

Similarly to diazepam, DF exerts anxiolytic effects that are blocked by flumazenil. Moreover, at the full anxiolytic dose of 2 mg/kg, DF lacks typical benzodiazepine-like side effects on motor and cognitive performances and on place conditioning. Moreover, DF fails to potentiate ethanol's (3 g/kg) depressant activity at the ethanol-induced Loss of Righting Reflex paradigm.

CONCLUSIONS

These data point to DF as an effective benzodiazepine-like anxiolytic compound that, in light of its lack of motor, mnemonic and motivational side effects, could be a suitable candidate for the treatment of anxiety disorders.

Endogenous opiates and behavior: 2019

This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

[Neurotransmitter changes in the rat brain under combined intoxication induced by alcohol and morphine]

We investigated the levels of biogenic monoamines and their metabolites in the rat hypothalamus, midbrain and cerebellum in acute complex intoxication with morphine and alcohol. The distinctive features of neurotransmitter disorders in various parts of the rat brain under a single exposure to ethanol and morphine, as well as the differences between acute morphine-alcohol and alcohol-morphine intoxication were established. Complex intoxication with alcohol and morphine resulted in signs of dopamine consumption only in the hypothalamus, regardless of the order of alcohol and morphine administration. Under conditions of alcohol-morphine intoxication an increase in the level of metabolites of the serotonergic system was noted in the investigated parts of the brain. In the midbrain and cerebellum the manifestation of combined action of ethanol and morphine is mainly determined by the effect of the last of the administered substances. There are features of changes in the indices of the dopaminergic and serotonergic systems in these experimental conditions, confirmed by the processes of dopamine catabolism and a decrease in the norepinephrine and serotonin concentration in the hypothalamus, which are not observed under individual action of ethanol and morphine.

Effect of Withania somnifera (L.) Dunal aqueous root extract on reinstatement using conditioned place preference and brain GABA and dopamine levels in alcohol dependent animals

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal (WS), a known'Rasayana' (rejuvenating agent) as per Ayurveda is prescribed to promote health, to increase longevity and to hasten recovery in disease convalescent stages. WS has demonstrated protective effect on alcohol dependence and withdrawal anxiety in previous experimental studies.

AIM OF THE STUDY

To evaluate effect of WS on conditioned place behavioral paradigm (model of relapse) and on GABA and dopamine levels in critical brain areas in alcohol dependent animals.

METHODOLOGY

Following Animal Ethics Committee permission, the mice (n = 24) were divided into the following study groups for experiment 1: 1 -distilled water (vehicle control), 2 -WS and 3 -Naltrexone. They were conditioned on conditioned place preference (CPP) using alcohol (2 gm/kg)/saline (1 ml) administered intraperitoneally for 8 days. WS and Naltrexone were administered during the period of extinction (6-8 days). Effect of WS (650 mg/kg) on reinstating behaviour of mice (time spent in alcohol paired compartment) primed with alcohol injection was noted. In experiment 2, effect of WS (450 mg/kg/) on GABA and dopamine levels in the midbrain, striatum and cortex (ng/gm) were measured in alcohol dependent rats (n = 24) following the first phase of standardisation assay (n = 36). The rats were made alcohol dependent for 15 days (intermittent access model) and WS was administered concurrently. GABA and dopamine levels were measured on Day 16.

RESULTS

WS group showed decrease in time spent in alcohol paired compartment alike Naltrexone and it differed significantly compared to the distilled water control group (p < 0.05) Alcohol-dependent rats showed significant decrease in GABA and increase in dopamine levels vs distilled water in the midbrain, striatum and cortex. WS and Naltrexone administration showed rise in GABA and fall in dopamine in all the isolated brain parts in the respective groups (p < 0.05 vs alcohol treated group).

CONCLUSION

Withania somnifera protected animals from relapse and showed beneficial effects on the brain neurotransmitters involved in alcohol dependence. The study provides substantial evidence for its potential application in alcohol use disorder.

Ethanol-Dependent Synthesis of Salsolinol in the Posterior Ventral Tegmental Area as Key Mechanism of Ethanol's Action on Mesolimbic Dopamine

Abnormal consumption of ethanol, the ingredient responsible for alcoholic drinks' addictive liability, causes millions of deaths yearly. Ethanol's addictive potential is triggered through activation, by a still unknown mechanism, of the mesolimbic dopamine (DA) system, part of a key motivation circuit, DA neurons in the posterior ventral tegmental area (pVTA) projecting to the ipsilateral nucleus accumbens shell (AcbSh). The present in vivo brain microdialysis study, in dually-implanted rats with one probe in the pVTA and another in the ipsilateral or contralateral AcbSh, demonstrates this mechanism. As a consequence of the oral administration of a pharmacologically relevant dose of ethanol, we simultaneously detect a) in the pVTA, a substance, 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol), untraceable under control conditions, product of condensation between DA and ethanol's first by-product, acetaldehyde; and b) in the AcbSh, a significant increase of DA release. Moreover, such newly generated salsolinol in the pVTA is responsible for increasing AcbSh DA release via μ opioid receptor (μOR) stimulation. In fact, inhibition of salsolinol's generation in the pVTA or blockade of pVTA μORs prevents ethanol-increased ipsilateral, but not contralateral, AcbSh DA release. This evidence discloses the long-sought key mechanism of ethanol's addictive potential and suggests the grounds for developing preventive and therapeutic strategies against abnormal consumption.

Impact of Caffeine on Ethanol-Induced Stimulation and Sensitization: Changes in ERK and DARPP-32 Phosphorylation in Nucleus Accumbens

BACKGROUND

Caffeine is frequently consumed with ethanol to reduce the impairing effects induced by ethanol, including psychomotor slowing or incoordination. Both drugs modulate dopamine (DA)-related markers in accumbens (Acb), and Acb DA is involved in voluntary locomotion and locomotor sensitization. The present study determined whether caffeine can affect locomotion induced by acute and repeated ethanol administration in adult male CD-1 mice.

METHODS

Acute administration of caffeine (7.5 to 30.0 mg/kg) was evaluated for its effects on acute ethanol-induced (1.5 to 3.5 g/kg) changes in open-field horizontal locomotion, supported rearing, and rearing not supported by the wall. DA receptor-dependent phosphorylation markers were assessed: extracellular signal-regulated kinase (pERK), and dopamine-and cAMP-regulated phosphoprotein Mr32kDa phosphorylated at threonine 75 site (pDARPP-32-Thr75) in Acb core and shell. Acutely administered caffeine was also evaluated in ethanol-sensitized (1.5 g/kg) mice.

RESULTS

Acute ethanol decreased both types of rearing. Caffeine increased supported rearing but did not block ethanol -induced decreases in rearing. Both substances increased horizontal locomotion in a biphasic manner, and caffeine potentiated ethanol-induced locomotion. Although ethanol administered repeatedly induced sensitization of locomotion and unsupported rearing, acute administration of caffeine to ethanol-sensitized mice in an ethanol-free state resulted in blunted stimulant effects compared with those seen in ethanol-naïve mice. Ethanol increased pERK immunoreactivity in both subregions of the Acb, but coadministration with caffeine blunted this increase. There were no effects on pDARPP-32(Thr75) immunoreactivity.

CONCLUSIONS

The present results demonstrated that, after the first administration, caffeine potentiated the stimulating actions of ethanol, but did not counteract its suppressant or ataxic effects. Moreover, our results show that caffeine has less activating effects in ethanol-sensitized animals.

Effects of Withania somnifera (Ashwagandha) on Stress and the Stress- Related Neuropsychiatric Disorders Anxiety, Depression, and Insomnia

BACKGROUND

Withania somnifera (WS), also known as Ashwagandha, is commonly used in Ayurveda and other traditional medicine systems. WS has seen an increase in worldwide usage due to its reputation as an adaptogen. This popularity has elicited increased scientific study of its biological effects, including a potential application for neuropsychiatric and neurodegenerative disorders.

OBJECTIVE

This review aims to provide a comprehensive summary of preclinical and clinical studies examining the neuropsychiatric effects of WS, specifically its application in stress, anxiety, depression, and insomnia.

METHODS

Reports of human trials and animal studies of WS were collected primarily from the PubMed, Scopus, and Google Scholar databases.

RESULTS

WS root and leaf extracts exhibited noteworthy anti-stress and anti-anxiety activity in animal and human studies. WS also improved symptoms of depression and insomnia, though fewer studies investigated these applications. WS may alleviate these conditions predominantly through modulation of the hypothalamic-pituitary-adrenal and sympathetic-adrenal-medullary axes, as well as through GABAergic and serotonergic pathways. While some studies link specific withanolide components to its neuropsychiatric benefits, there is evidence for the presence of additional, as yet unidentified, active compounds in WS.

CONCLUSION

While benefits were seen in the reviewed studies, significant variability in the WS extracts examined prevents a consensus on the optimum WS preparation or dosage for treating neuropsychiatric conditions. WS generally appears safe for human use; however, it will be important to investigate potential herb-drug interactions involving WS if used alongside pharmaceutical interventions. Further elucidation of active compounds of WS is also needed.

Plants with Anti-Addictive Potential

Drug addiction is prevalent among individuals of modern society, being a major cause of disability and premature loss of life. Although the drug addiction have profound social, economical and health impact in the world population, its management remains a challenge as available pharmacological treatments remains ineffective for most people. The limited efficacy and adverse effects have led to a search for alternative therapies to treat drug addiction. In this context, natural products are an important source for new chemical substances with a potential therapeutic applicability. Therefore, this chapter will present data obtained after an extensive literature search regarding the use of medicinal plants as a pharmacological alternative for drug addiction treatment.

Withania somnifera L.: Insights into the phytochemical profile, therapeutic potential, clinical trials, and future prospective

Withania somnifera L. is a multipurpose medicinal plant of family Solanaceae occurring abundantly in sub-tropical regions of the world. The folk healers used the plant to treat several diseases such as fever, cancer, asthma, diabetes, ulcer, hepatitis, eyesores, arthritis, heart problems, and hemorrhoids. The plant is famous for the anti-cancerous activity, low back pain treatment, and muscle strengthening, which may be attributed to the withanolide alkaloids. W. somnifera is also rich in numerous valued secondary metabolites such as steroids, alkaloids, flavonoids, phenolics, saponins, and glycosides. A wide range of preclinical trials such as cardioprotective, anticancer, antioxidant, antibacterial, antifungal, anti-inflammatory, hepatoprotective, anti-depressant, and hypoglycemic have been attributed to various parts of the plant. Different parts of the plant have also been evaluated for the clinical trials such as male infertility, obsessive-compulsive disorder, antianxiety, bone and muscle strengthening potential, hypolipidemic, and antidiabetic. This review focuses on folk medicinal uses, phytochemistry, pharmacological, and nutrapharmaceutical potential of the versatile plant.

Ashwagandha in brain disorders: A review of recent developments

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (Family: Solanaceae), commonly known as Ashwagandha or Indian ginseng is distributed widely in India, Nepal, China and Yemen. The roots of plant consist of active phytoconstituents mainly withanolides, alkaloids and sitoindosides and are conventionally used for the treatment of multiple brain disorders.

AIM OF THE REVIEW

This review aims to critically assess and summarize the current state and implication of Ashwagandha in brain disorders. We have mainly focussed on the reported neuroactive phytoconstituents, available marketed products, pharmacological studies, mechanism of action and recent patents published related to neuroprotective effects of Ashwagandha in brain disorders.

MATERIALS AND METHODS

All the information and data was collected on Ashwagandha using keywords "Ashwagandha" along with "Phytoconstituents", "Ayurvedic, Unani and Homeopathy marketed formulation", "Brain disorders", "Mechanism" and "Patents". Following sources were searched for data collection: electronic scientific databases such as Science Direct, Google Scholar, Elsevier, PubMed, Wiley On-line Library, Taylor and Francis, Springer; books such as AYUSH Pharmacopoeia; authentic textbooks and formularies.

RESULTS

Identified neuroprotective phytoconstituents of Ashwagandha are sitoindosides VII-X, withaferin A, withanosides IV, withanols, withanolide A, withanolide B, anaferine, beta-sitosterol, withanolide D with key pharmacological effects in brain disorders mainly anxiety, Alzheimer's, Parkinson's, Schizophrenia, Huntington's disease, dyslexia, depression, autism, addiction, amyotrophic lateral sclerosis, attention deficit hyperactivity disorder and bipolar disorders. The literature survey does not highlight any toxic effects of Ashwagandha. Further, multiple available marketed products and patents recognized its beneficial role in various brain disorders; however, very few data is available on mechanistic pathway and clinical studies of Ashwagandha for various brain disorders is scarce and not promising.

CONCLUSION

The review concludes the results of recent studies on Ashwagandha suggesting its extensive potential as neuroprotective in various brain disorders as supported by preclinical studies, clinical trials and published patents. However vague understanding of the mechanistic pathways involved in imparting the neuroprotective effect of Ashwagandha warrants further study to promote it as a promising drug candidate.