Hemant K. Singh

A comparative study in rodents of standardized extracts of Bacopa monniera and Ginkgo biloba: Anticholinesterase and cognitive enhancing activities

Bacopa monniera and Ginkgo biloba are well-known cognitive enhancers in Indian and Chinese traditional medicine systems. Standardized extracts of B. monniera and G. biloba were used to evaluate the antidementic and anticholinesterase activities in adult male Swiss mice. Antidementic activity was tested against scopolamine (3 mg/kg ip)-induced deficits in passive avoidance test. Three different extracts of B. monniera (30 mg/kg) and extract of G. biloba (15, 30 and 60 mg/kg) were administered postoperatively, daily for 7 days and 60 min after the last dose, i.e., on Day 7, first trial was conducted. In passive avoidance test, increased transfer latency time (TLT) and no transfer response (NTR) were taken as criteria for learning. TLT and NTR were significantly increased and decreased in second trial, 24 h after the first trial in control group and scopolamine-dementia group, respectively. The B. monniera- and G. biloba-treated groups produced significant increase in TLT and NTR on second trial (40-80%) after scopolamine treatment, thus, attenuating its antidementic effect. Both the extracts showed a dose (10-1000 microg)-dependent inhibitory effect on acetylcholinesterase (AChE) activity (in vitro), performed spectrophotometrically. IC(50) of G. biloba was 268.33 microg, whereas none of the extracts of B. monniera showed more than 50% inhibition. At a dose concentration of 30 and 60 mg/kg, extracts of G. biloba showed a cognitive enhancing property and, at the same time, a significant decrease in AChE-specific activity in both per se and scopolamine-dementia groups. These extracts possess a significant anticholinesterase and antidementic properties, which may be useful in the treatment of dementia.

Adaptogenic effect of Bacopa monniera (Brahmi)

As stress is linked to many diseases, research on an effective antistress agent (adaptogen) from plants has gained importance. We report the investigations on the adaptogenic property of a standardized extract of Bacopa monniera against acute (AS) and chronic stress (CS) models in rats. Panax root powder (Panax quinquefolium) was taken as a standard. Male SD rats, weighing 180-200 g, exposed to immobilization stress for 150 min once only for AS and for seven consecutive days in CS, were fed with B. monniera or Panax root powder daily for 3 days in AS and for 7 days in CS, 45 min prior to each exposure of stress. Rats were sacrificed immediately after stress, the blood was collected, and the plasma was separated out for biochemical estimation. Adrenals, spleen, and thymus were dissected for organ weight and stomach for ulcer score. AS exposure significantly increased the ulcer index, adrenal gland weight, plasma glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK) but significantly decreased the spleen weight. Pretreatment with B. monniera at 40 mg/kg po significantly reduced the AS-induced increase in the ulcer index, adrenal gland weight, plasma glucose, AST, and CK. A dose of 80 mg/kg po significantly reversed the AS-induced changes in adrenal gland weight, spleen weight, plasma glucose, ALT, and AST. Panax root powder, 100 mg/kg po, significantly reversed the AS-induced changes in spleen weight, plasma ALT, AST, and CK. CS exposure resulted in a significant increase in the ulcer index, adrenal gland weight, plasma AST, and CK with a significant decrease in the thymus and spleen weight, plasma triglyceride, and cholesterol. Pretreatment with low dose of B. monniera extract at 40 mg/kg significantly reversed changes in ulcer index and plasma AST only, whereas the pretreatment with higher dose significantly reversed CS-induced changes in ulcer index, adrenal gland weight, CK, and AST. Panax root powder significantly reversed CS-induced increase in ulcer index, adrenal gland weight, CK, and AST. On the basis of our result, it is concluded that the standardized extract of B. monniera possesses a potent adaptogenic activity.

Standardized extract of Bacopa monniera (BESEB CDRI‐08) attenuates contextual associative learning deficits in the aging rat's brain induced by D‐galactose

In this study, we examined the neuroprotective effect of standardized Bacopa monniera extract (BME: BESEB CDRI‐08) against the D‐galactose (D‐gal)‐induced brain aging in rats. Experimental groups were subjected to contextual‐associative learning task. We found that the administration of BME in the D‐gal‐treated group attenuated contextual‐associative learning deficits; the individuals showed more correct responses and retrieved the reward with less latency. Subsequent analysis showed that the BME administration significantly decreased advance glycation end product (AGE) in serum and increased the activity of antioxidant response element (ARE) and the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), and nuclear transcription factor NF‐E2‐related factor 2 (Nrf2), accompanied by a reduction in the level of serotonin (5‐HT) in the hippocampus. The BME treatment also reversed D‐gal‐induced brain aging by upregulating the levels of the presynaptic proteins synaptotagmin I (SYT1) and synaptophysin (SYP) and the postsynaptic proteins Ca2+/calmodulin dependent protein kinase II (αCaMKII) and postsynaptic density protein‐95 (PSD‐95) in the hippocampus during synaptic plasticity. A significant finding is that the D‐gal‐ + BME‐treated rats exhibited more correct responses in contextual‐associative learning than D‐gal alone‐treated rats. Our findings suggest that BME treatment attenuates D‐gal‐induced brain aging and regulates the level of antioxidant enzymes, Nrf2 expression, and the level of 5‐HT, which was accompanied by concomitantly increased levels of synaptic proteins SYT1, SYP, αCaMKII, p‐αCaMKII, and PSD‐95.

Attenuation of 1-( m -Chlorophenyl)-Biguanide Induced Hippocampus-Dependent Memory Impairment by a Standardised Extract of Bacopa monniera (BESEB CDRI-08)

Bacopa monniera is a well-known medhya-rasayana (memory enhancing and rejuvenating) plant in Indian traditional medical system of Ayurveda. The effect of a standardized extract of Bacopa monniera (BESEB CDRI-08) on serotonergic receptors and its influence on other neurotransmitters during hippocampal-dependent learning was evaluated in the present study. Wistar rat pups received a single dose of BESEB CDRI-08 during postnatal days 15–29 showed higher latency during hippocampal-dependent learning accompanied with enhanced 5HT3A receptor expression, serotonin and acetylcholine levels in hippocampus. Furthermore, 5HT3A receptor agonist 1-(m-chlorophenyl)-biguanide (mCPBG) impaired learning in the passive avoidance task followed by reduction of 5HT3A receptor expression, 5HT and ACh levels. Administration of BESEB CDRI-08 along with mCPBG attenuated mCPBG induced behavioral, molecular and neurochemical alterations. Our results suggest that BESEB CDRI-08 possibly acts on serotonergic system, which in turn influences the cholinergic system through 5-HT3 receptor to improve the hippocampal-dependent task.

Nootropic potential of Alternanthera sessilis and Clerodendrum infortunatum leaves on mice

Abstract Objective To ascertain the nootropic potential (memory enhancing effects) of the leaves of Alternanthera sessilis (Amaranthaceae) and Clerodendrum infortunatum (Verbenaceae) using rectangular maze and Y maze (interoceptive behavioral models) Methods Methanolic extracts of leaves Alternanthera sessilis and Clerodendrum infortunatum dosed at 100 and 200 mg/kg each were administered to adult Swiss albino Wistar mice and the effect on acquisition, retention and retrieval of spatial recognition memory was determined. Bacopa monniera extract was used as the standard drug while Scopolamine hydrobromide served as the amnestic agent. Results The higher doses of both the extracts exhibited a more promising nootropic potential. Maximal response was observed in the 200 mg/kg dose of Clerodendrum infortunatum methanolic extract, which closely approximated the results for the standard drug Brahmi. Both the higher doses elicited greater responses in both the models studied and were comparable to that achieved with the standard drug. Conclusions The methanolic extracts of Clerodendrum infortunatum afforded greater memory enhancing effects in comparison to Alternanthera sessilis extract, the higher dose evoking pronounced alteration behavior and better learning assessments.

Possible Involvement of Standardized Bacopa monniera Extract (CDRI-08) in Epigenetic Regulation of reelin and Brain-Derived Neurotrophic Factor to Enhance Memory

Bacopa monniera extract (CDRI-08; BME) has been known to improve learning and memory, and understanding the molecular mechanisms may help to know its specificity. We investigated whether the BME treatment alters the methylation status of reelin and brain-derived neurotropic factor (BDNF) to enhance the memory through the interaction of N-methyl-D-aspartate receptor (NMDAR) with synaptic proteins. Rat pups were subjected to novel object recognition test following daily oral administration of BME (80 mg/kg) in 0.5% gum acacia (per-orally, p.o.; PND 15–29)/three doses of 5-azacytidine (5-azaC; 3.2 mg/kg) in 0.9% saline (intraperitoneally, i.p.) on PND-30. After the behavioral test, methylation status of reelin, BDNF and activation of NMDAR, and its interactions with synaptic proteins were tested. Rat pups treated with BME/5-azaC showed higher discrimination towards novel objects than with old objects during testing. Further, we observed an elevated level of unmethylated DNA in reelin and BDNF promoter region. Up-regulated reelin along with the splice variant of apolipoprotein E receptor 2 (ApoER 2, ex 19) form a cluster and activate NMDAR through disabled adopter protein-1 (DAB1) to enhance BDNF. Observed results suggest that BME regulate reelin epigenetically, which might enhance NMDAR interactions with synaptic proteins and induction of BDNF. These changes may be linked with improved novel object recognition memory.

Molecular Docking of Bacosides with Tryptophan Hydroxylase: A Model to Understand the Bacosides Mechanism

Tryptophan hydroxylase (TPH) catalyses l-tryptophan into 5-hydroxy-l-tryptophan, which is the first and rate-limiting step of serotonin (5-HT) biosynthesis. Earlier, we found that TPH2 up-regulated in the hippocampus of postnatal rats after the oral treatment of Bacopa monniera leaf extract containing the active compound bacosides. However, the knowledge about the interactions between bacosides with TPH is limited. In this study, we take advantage of in silico approach to understand the interaction of bacoside-TPH complex using three different docking algorithms such as HexDock, PatchDock and AutoDock. All these three algorithms showed that bacoside A and A3 well fit into the cavity consists of active sites. Further, our analysis revealed that major active compounds bacoside A3 and A interact with different residues of TPH through hydrogen bond. Interestingly, Tyr235, Thr265 and Glu317 are the key residues among them, but none of them are either at tryptophan or BH4 binding region. However, its note worthy to mention that Tyr 235 is a catalytic sensitive residue, Thr265 is present in the flexible loop region and Glu317 is known to interacts with Fe. Interactions with these residues may critically regulate TPH function and thus serotonin synthesis. Our study suggested that the interaction of bacosides (A3/A) with TPH might up-regulate its activity to elevate the biosynthesis of 5-HT, thereby enhances learning and memory formation.

Detection and quantitation of gallic acid in Alternanthera sessilis and Clerodendrum infortunatum by HPTLC

Objective: Gallic acid is an organic acid found in a variety of foods and medicinal plants that are well known as powerful antioxidants, and have along history of usage traditionally. Many Foods, herbs and tea all contain Gallic acid. Gallic acid is also found in gall nuts, sumac, witch hazel, watercress, oak bark, and a variety of other plants and herbs, also found in important Indian Medicinal Plants like Alternanthera sessilis and Clerodendrum infortunatum as mentioned in Ayurveda, in intellect enhancing preparations, later explored as part of tannins, which are astringent, bitter plant polyphenols. The age old Indian System of Medicine, i.e. Ayurveda is based on traditional way of maintaining a healthy lifestyle and living in sync with the nature, thereby reducing or delaying the onset of any degrading / diseased condition involving neurological disorders. Leaves of Alternanthera sessilis (Family Amaranthaceae) and Clerodendrum infortunatum (Family Verbenaceae) have been mentioned in Ayurveda but have not been fully explored scientifically. Materials and Methods: It was thought worthwhile to generate experimental data on the plant material so as to explore some markers present in these plants, like Gallic Acid, which may be useful for future ready reference and may also serve as a parameter in Standardization and Quality Control / Adulteration studies. Gallic Acid has already captured researchers interest due to its effect on nervous system. Results: The concentration of Gallic Acid in leaves of Alternanthera sessilis and Clerodendrum infortunatum was found to be 8.022μg/mL and 8.54μg/mL respectively. Conclusion: The Data thus generated in present research work may be of use in future studies involving development of standardization /adulteration / substitution parameters on Alternanthera sessilis & Clerodendrum infortunatum. It is known that the present day lifestyle invariably results in Oxidative stress which results in an imbalance between high consumption of oxygen and low levels of endogenous antioxidants. It is known that Gallic acid (GA) is a strong antioxidant. It is pertinent to state that Gallic Acid may be considered as a marker for future studies on medicinal plants, related to Neuropsychopharmacological investigations mainly involving oxidative stress.