Antidepressant activity of standardised extract of Marsilea minuta Linn.
OBJECTIVE
Marsilea minuta Linn. (Marsileaceae) has been referred in Indian traditional medicine system (Ayurveda) for the treatment of insomnia and other mental disorders. Marsiline isolated from Marsilea minuta was reported to have sedative and anticonvulsant property. The ethanol extract of Marsilea minuta was standardised for marsiline (1.15%, w/w) and studied for its antidepressant activity.


METHODS
Antidepressant activity was studied using forced swimming test (FST), tail suspension test (TST), learned helplessness test (LHT) and 5-hydroxytryptophan (5-HTP) induced head twitches response in rodents. Standardised extract of Marsilea minuta in doses of 100, 200 and 400 mg/kg/day were administered orally for three consecutive days and evaluated on day 3, 1h after the last dose treatment. Imipramine (15 mg/kg/day, i.p.) was used as the standard drug. Neurochemical mechanism of antidepressant activity was elucidated by using radioligand receptor binding assays for 5-HT2A and benzodiazepine receptors in rat frontal cortex.


RESULTS
Immobility time in FST and TST was significantly (P<0.05) reduced by ethanol extract of Marsilea minuta treated animals. A decrease in number of escape failures in LHT was also observed in Marsilea minuta treated rats. Head twitch response induced by 5-HTP was significantly attenuated by Marsilea minuta (400 mg/kg, p.o.) and imipramine showing the involvement of serotonergic system. This effect was corroborated with radioligand receptor binding study where Marsilea minuta (400 mg/kg, p.o.) significantly (P<0.05) down regulated 5-HT2A receptor in frontal cortex, whereas, no marked effect was observed for benzodiazepine receptor.


CONCLUSIONS
The antidepressant effect exhibited by Marsilea minuta extract may be due to its effect on 5-HT2A density in rat frontal cortex.
Bhattamisra
Subrat Kumar
SK
Neuropharmacology Laboratory, Department of Pharmaceutics, Institute of Technology, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India. bhattamisra@yahoo.co.in
Khanna
Vinay Kumar
VK
Agrawal
Ashok Kumar
AK
Singh
Paras Nath
PN
Singh
Sushil Kumar
SK
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D005260:Female; D005445:Flunitrazepam / Q000378:metabolism; D019417:Hindlimb Suspension; D007650:Ketanserin / Q000378:metabolism; D008297:Male; D043964:Marsileaceae; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D058830:Serotonin 5-HT2 Receptor Antagonists; D013550:Swimming
D000928:Antidepressive Agents; D010936:Plant Extracts; D058830:Serotonin 5-HT2 Receptor Antagonists; D005445:Flunitrazepam; D007650:Ketanserin; D006916:5-Hydroxytryptophan