Subrat Kumar Bhattamisra1, Paras Nath Singh, Sushil Kumar Singh. 1. Neuropharmacology Laboratory, Department of Pharmaceutics, Institute of Technology, Banaras Hindu University, Varanasi, Uttar Pradesh, India. bhattamisra@yahoo.co.in
Abstract
CONTEXT: Marsilea minuta Linn (Marsileaceae) is a common Indian hydrophytic plant. Traditionally, the plant has been used as a sedative for the treatment of insomnia and other mental disorders. Background information of this plant has encouraged us to investigate its antiamnesic activity in rat. OBJECTIVE: Standardized ethanol extract of M. minuta was investigated for their putative role in learning and memory performance in normal and amnesic rats. MATERIALS AND METHODS: Ethanol extract of M. minuta (EMM) was standardized for marsiline using HPLC. The effect of standardized extract of M. minuta (1.15% w/w marsiline) was tested in amnesic rat using elevated plus maze (EPM) and passive avoidance (PA) test. Amnesia was induced after scopolamine (1 mg/kg, s.c.) and electroconvulsive shock (150 mA, 0.2 s) treatment. Behavioral studies were further substantiated with acetylcholinesterase (AChE) activity and radioligand muscarinic receptor binding studies in rat brain regions. RESULTS: Oral administration of EMM at 200 and 400 mg/kg/day for 3 days significantly reversed the amnesia whereas, no per se effect was observed. In comparison to control, AChE activity in frontal cortex and hippocampus was found to be significantly (P < 0.05) inhibited by EMM. EMM at doses 200 and 400 mg/kg has significantly (P < 0.05) increased (+34 % and +40 % change in affinity, respectively) the binding of 3H-QNB in frontal cortex indicating the up regulation of the muscarinic receptors. DISCUSSION AND CONCLUSION: These findings suggest that standardized extract of M. minuta have excellent antiamnesic activity, probably mediating through central cholinergic system.
CONTEXT: Marsilea minuta Linn (Marsileaceae) is a common Indian hydrophytic plant. Traditionally, the plant has been used as a sedative for the treatment of insomnia and other mental disorders. Background information of this plant has encouraged us to investigate its antiamnesic activity in rat. OBJECTIVE: Standardized ethanol extract of M. minuta was investigated for their putative role in learning and memory performance in normal and amnesicrats. MATERIALS AND METHODS:Ethanol extract of M. minuta (EMM) was standardized for marsiline using HPLC. The effect of standardized extract of M. minuta (1.15% w/w marsiline) was tested in amnesicrat using elevated plus maze (EPM) and passive avoidance (PA) test. Amnesia was induced after scopolamine (1 mg/kg, s.c.) and electroconvulsive shock (150 mA, 0.2 s) treatment. Behavioral studies were further substantiated with acetylcholinesterase (AChE) activity and radioligand muscarinic receptor binding studies in rat brain regions. RESULTS: Oral administration of EMM at 200 and 400 mg/kg/day for 3 days significantly reversed the amnesia whereas, no per se effect was observed. In comparison to control, AChE activity in frontal cortex and hippocampus was found to be significantly (P < 0.05) inhibited by EMM. EMM at doses 200 and 400 mg/kg has significantly (P < 0.05) increased (+34 % and +40 % change in affinity, respectively) the binding of 3H-QNB in frontal cortex indicating the up regulation of the muscarinic receptors. DISCUSSION AND CONCLUSION: These findings suggest that standardized extract of M. minuta have excellent antiamnesic activity, probably mediating through central cholinergic system.