Dinesh Y. Gawande

Pharmacological validation of in-silico guided novel nootropic potential of Achyranthes aspera L.

ETHNOPHARMACOLOGICAL RELEVANCE Achyranthes aspera (A. aspera) has been used as a brain tonic in folk medicine. Although, ethnic use of medicinal plant has been basis for drug discovery from medicinal plants, but the available in-silico tools can be useful to find novel pharmacological uses of medicinal plants beyond their ethnic use. AIM OF THE STUDY To validate in-silico prediction for novel nootropic effect of A. aspera by employing battery of tests in mice. MATERIAL AND METHODS Phytoconstituents of A. aspera reported in Dictionary of Natural Product were subjected to in-silico prediction using PASS and Pharmaexpert. The nootropic activity predicted for A. aspera was assessed using radial arm maze, passive shock avoidance and novel object recognition tests in mice. After behavioral evaluation animals were decapitated and their brains were collected and stored for estimation of glutamate levels and acetylcholinesterase activity. RESULTS In-silico activity spectrum for majority of A. aspera phytoconstituents exhibited excellent prediction score for nootropic activity of this plant. A. aspera extract treatment significantly improved the learning and memory as evident by decreased working memory errors, reference memory errors and latency time in radial arm maze, step through latency in passive shock avoidance and increased recognition index in novel object recognition were observed, moreover significantly enhanced glutamate levels and reduced acetylcholinesterase activity in hippocampus and cortex were observed as compared to the saline treated group. CONCLUSION In-silico and in-vivo results suggest that A. aspera plant may improve the learning and memory by modulating the brain glutamatergic and cholinergic neurotransmission.

Revealing pharmacodynamics of medicinal plants using in silico approach: A case study with wet lab validation

BACKGROUND Exploration of therapeutic mechanism is an integral part of medicinal plant based drug discovery for better understanding of pharmacological behavior of these agents. But, its study using conventional hit and trial wet laboratory experiments proves to be very tedious, time consuming and expensive, thus encouraging development of in silico techniques. Hence, an in silico technique has been devised using a computer software Prediction of Activity Spectra for Substances (PASS) to study pharmacodynamics of medicinal plants. The technique has been presented with a case study using Ficus religiosa L. (Moraceae) in which its anticonvulsant mechanism has been elucidated with PASS and further validated experimentally. METHODS Pentylenetetrazol (PTZ)-induced convulsion test was used to study the anticonvulsant effect of standardized bark extract of F. religiosa. Thereafter, structure of all the reported bioactive metabolites in the bark was subjected to PASS software to obtain biological activity spectrum of each compound. The mechanism signifying anticonvulsant effect was selected from the spectrum and was further validated using in vitro test. RESULTS AND DISCUSSION The extract showed significant anticonvulsant effect in PTZ test. PASS analysis showed a high activity score for GABA aminotransferase (GABA-AT) inhibitory effect of the bioactive metabolites present in the bark. In vitro GABA-AT enzyme assay results were in concordance with the predicted mechanism by PASS for the observed anticonvulsant effect, as the extract showed potent inhibition of the enzyme. The results of present study showed the in silico technique to be useful for elucidation of unknown therapeutic mechanisms of medicinal plants.

Revealing Medicinal Plants That Are Useful for the Comprehensive Management of Epilepsy and Associated Comorbidities through In Silico Mining of Their Phytochemical Diversity.

In silico techniques in drug discovery may rationalise and speed up the identification of lead molecules from nature. Drug discovery from medicinal plants has mostly been confined to indications in accordance with their ethnical use only. However, the availability of multiple phytoconstituents in medicinal plants suggests that these may be much more useful beyond their traditional uses and in the management of chronic diseases, along with their comorbidities. In this study, the computer programmes PASS and PharmaExpert were used to reveal the medicinal plants useful in the comprehensive management of epilepsy and associated psychiatric disorders based on the pleiotropic effects predicted for their phytoconstituents. In silico analysis revealed that seven of 50 medicinal plants from traditional Indian medicine possessed the desired pleiotropic effect, i.e., anticonvulsant, antidepressant, and nootropic activities. The majority of phytoconstituents from Passiflora incarnata were concurrently predicted to have the desired pleiotropic effects. Therefore, P. incarnata was pharmacologically validated using the pentylenetetrazole kindling mouse model. Behavioural and neurochemical evaluations confirmed the ameliorative role of P. incarnata in epilepsy and the associated depression and memory deficit. The pharmacological findings from this study propose that PASS and PharmaExpert may serve as good tools for the optimisation of the selection of plants based on their phytoconstituents for the treatment of different ailments, even beyond their traditional use.

Anticonvulsant activity and acute neurotoxic profile of Achyranthes aspera Linn.

ETHNOPHARMACOLOGICAL RELEVANCE Root powder of Achyranthes aspera Linn. (A. aspera) belongs to family Amaranthaceae is used in Indian traditional medicine for the management of epilepsy and its efficacy is widely acclaimed among the different rural communities. AIM OF THE STUDY The present study was aimed to establish the possible anticonvulsant effect of A. aspera methanolic root extract using acute anticonvulsant models and to evaluate the acute toxicity and neurotoxic potential A. aspera extract. MATERIAL AND METHODS A. aspera methanolic extract was standardized with respect to betaine using HPTLC. The maximal electroshock (MES), pentylenetetrazol (PTZ), picrotoxin and bicuculline induced seizure models were used to evaluate the anticonvulsant potential of standardized A. aspera root extract. The GABA content in cortex and hippocampus of extract treated mice was evaluated using HPLC. Moreover, the animals were also evaluated for acute toxicity study and neurotoxicity test. RESULTS A significant enhancement in the seizure threshold was observed by A. aspera extract (5 and 10mg/kg) treated mice in PTZ, picrotoxin and bicuculline models as compared to saline treated mice respectively, whereas the extract failed to show protection in MES induced seizures. Moreover, A. aspera treatment (5 and 10mg/kg) significantly enhances the GABA levels in hippocampus and cortex as compared to saline treated group. A. aspera root extract was devoid of any sign of acute toxicity as well as neurotoxicity. CONCLUSIONS A. aspera root extract exhibits significant anticonvulsant effect by facilitation of GABAergic neurotransmission in the brain.

Agmatine ameliorates adjuvant induced arthritis and inflammatory cachexia in rats

The present study investigated the pharmacological effect of agmatine in Complete Freud Adjuvant (CFA) induced arthritis and cachexia in rats. The rats were injected with CFA (0.1ml/rat) to induced symptoms of arthritis. Day 8 onwards of CFA administration, rats were injected daily with agmatine for next 7days, and arthritis score, body weights and food intake were monitored daily (g). Since cachexia is known to produce severe inflammation, malnutrition and inhibition of albumin gene expression, we have also monitored the total proteins, albumin, TNF-α and IL-6 levels in arthritic rats and its modulation by agmatine. In the present study, CFA treated rats showed a progressive reduction in both food intake and body weight. In addition analysis of blood serum of arthritis animals showed a significant reduction in proteins and albumin and significant elevation in tumor necrosis factor (TNF)-α and Interleukins (IL)-6. Chronic agmatine (20-40mg/kg, ip) treatment not only attenuated the signs of arthritis but also reverses anorexia and body weight loss in CFA treated rats. In addition, agmatine restored total protein and albumin and reduces TNF-α and IL-6 levels in arthritis rats. These results suggest that agmatine administration can prevent the body weights loss and symptoms of arthritis via inhibition of inflammatory cytokines.

Agmatine for combined treatment of epilepsy, depression and cognitive impairment in chronic epileptic animals

Epilepsy is fourth most common neurological disorders associated with depression and cognitive deficits. As per present scenario, none of the antiseizure drugs have been reported successful to have ameliorative effect on epilepsy associated depression and cognitive deficits. Thus, the study was envisioned to assess an ameliorative potential of agmatine on epilepsy and its efficacy and safety for management of associated depression and cognitive deficits. The animals were made epileptic employing pentylenetetrazole (35mg/kg i.p. every 48±2h) kindling model of epilepsy and subsequently were treated with vehicle, valproic acid (300mg/kg/day i.p.) and agmatine (2.5, 5, and 10mg/kg)/day/i.p. for 15days. Except naïve, all the groups were challenged with same pentylenetetrazole dose as employed during kindling on days 5, 10, and 15 to evaluate seizure severity. Two hours after seizure severity test, tail suspension test and passive shock avoidance paradigm was employed to evaluate depression and cognitive behavior respectively. Results suggested that epileptic animals were significantly associated with depression and cognitive impairment. Chronic valproate treatment significantly reduced seizure severity, but was found unable to mitigate depression and cognitive deficits. However, agmatine treatment dose dependently ameliorated seizure severity as well as associated depression and cognitive deficits. On 15th day, animals were euthanized and pertinent neurochemical estimations were carried out in cortical and hippocampal areas of the mice brain. Thus, study concluded that agmatine ameliorated seizure severity, depression and cognitive impairment in epileptic animals, possibly via restoring glutamate-GABA neurotransmission and serotonin synthesis with decreased nitrosative stress.

Capacities of computer evaluation of hidden potential of phytochemicals of medicinal plants of the traditional Indian Ayurvedic medicine

Applicability of our computer programs PASS and PharmaExpert for prediction of biological activity spectra of rather complex and structurally diverse phytocomponents of medicinal plants, both separately and in combinations has been evaluated. For this purpose we have created the web-resource containing known information about structural formulas and biological activity of 1906 phytocomponents of 50 Ayurvedic medicinal plants used in Traditional Indian Medicine (TIM) (http://ayurveda.pharmaexpert.ru). The PASS training set was updated by addition of information about structure and biological activity of 946 natural compounds; then the training procedure and validation were performed, to estimate the quality of PASS prediction. It was shown that the differences between the average accuracy of prediction obtained in leave-5%-out cross-validation (94.467%) and in leave-one-out cross-validation (94.605%) are very small thus demonstrating high predictive ability of the program. Results of biological activity spectra prediction for all phytocomponents included in our database coincided in 83.5% of cases with known experimental data. Additional types of biological activity predicted with high probability indicate further promising directions for further studies of certain phytocomponents of some medicinal plants. The analysis of prediction results of sets of phytocomponents in each of 50 medicinal plants was made by the PharmaExpert software. Based on this analysis, we found that the combination of phytocomponents from Passiflora incarnata may exhibit nootropic, anticonvulsant, and antidepressant effects. Experiments carried out in mice models confirmed the predicted effects of P. incarnata extracts.

Computer evaluation of hidden potential of phytochemicals of medicinal plants of the traditional Indian ayurvedic medicine

Applicability of our computer programs PASS and PharmaExpert to prediction of biological activity spectra of rather complex and structurally diverse phytocomponents of medicinal plants, both separately and in combinations has been evaluated. The web-resource on phytochemicals of 50 medicinal plants used in Ayurveda was created for the study of hidden therapeutic potential of Traditional Indian Medicine (TIM) (http://ayurveda.pharmaexpert.ru). It contains information on 50 medicinal plants, their using in TIM and their pharmacology activities, also as 1906 phytocomponents. PASS training set was updated by addition of information about 946 natural compounds; then the training procedure and validation were performed, to estimate the quality of PASS prediction. It was shown that the difference between the average accuracy of prediction obtained in leave-5%-out cross-validation (94,467%) and in leave-one-out cross-validation (94,605%) is very small. These results showed high predictive ability of the program. Results of biological activity spectra prediction for all phytocomponents included in our database are in good correspondence with the experimental data. Additional kinds of biological activity predicted with high probability provide the information about most promising directions of further studies. The analysis of prediction results of sets of phytocomponents in each of 50 medicinal plants was made by PharmaExpert software. Based on this analysis, we found that the combination of phytocomponents from Passiflora incarnata may exhibit nootropic, anticonvulsant and antidepressant effects. Experiments carried out in mice models confirmed the predicted effects of Passiflora incarnata extracts.

Acute orexigenic effect of agmatine involves interaction between central α2-adrenergic and GABAergic receptors

Agmatine and GABA have been abundantly expressed in brain nuclei involved in regulation of energy homeostasis and promoting stimulation of food intake in rodents. However, their mutual interaction, if any, in the elicitation of feeding behavior is largely remains unclear. The current study provides experimental evidence for the possible interaction of agmatine, adrenergic and GABAergic systems in stimulation of feeding in satiated rats. Satiated rats fitted with intracerebroventricular (i.c.v.) cannulae and were administered agmatine, alone or jointly with (a) GABAA receptor agonist, muscimol, diazepam or antagonist bicuculline and flumazenil, GABAA positive modulator, allopregnanolone or negative modulator of GABAA receptor, dehydroepiandrosterone (b) In view of the high affinity of agmatine for α2-adrenoceptors and the close association between α2-adrenoceptors and GABAergic system, the effect of their modulators on feeding elicited by agmatine/GABAergic agonists were also examined. I.c.v. administration of agmatine (40-80μg/rat) induces the significant orexigenic effect in satiated rats. The orexigenic effect of agmatine was potentiated by muscimol (25ng/rat, i.c.v.); diazepam (0.5mg/kg, i.p.); allopregnanolone (0.5mg/kg, s.c.) and blocked by bicuculline (1mg/kg, i.p.) and dehydroepiandrosterone (4mg/kg,s.c.). However, it remained unaffected in presence of flumazenil (25ng/rat, i.c.v.). The orexigenic effect of agmatine and GABAergic agonists was potentiated by a α2-adrenoceptors agonist, clonidine (10ng/rat, i.c.v.) and blocked by its antagonist, yohimbine (5μg/rat, i.c.v.). Yohimbine also blocked the hyperphagic effect elicited by ineffective dose combination of agmatine (5μg/rat, i.c.v.) with muscimol (25ng/rat, i.c.v.) or diazepam (0.5mg/kg, i.p.) or allopregnanolone (0.5mg/kg,s.c.). The results of the present study suggest that agmatine induced α2-adrenoceptors activation might facilitate GABAergic activity to stimulate food intake in satiated rats.