Antidopaminergic activity of isoflavone isolated from Butea monosperma flowers
Bioassay guided fractionation of methanolic extract of Butea monosperma Kuntz (Fabaceae) flowers was carried out using inhibition of dopamine-induced contraction of rat vas deferens as a biological end point. The antidopaminergic activity was present in the ethyl acetate soluble fraction of the methanolic extract and the antagonism between the extract and dopamine was non-competitive in nature. Further separation of the ethyl acetate fraction by preparatory chromatography yielded a compound, suggested to belong to the isoflavone series on the basis of its UV spectrum . The antidopaminergic activity was assessed using haloperidol-induced catalepsy using bar test2 and foot shock-induced aggression in rats3. The methanolic extract, its ethyl acetate soluble fraction, and the isoflavone were used in doses of 50 and 100mg/kg i.p. The methanolic extract, its ethyl acetate soluble fraction and the isoflavone when used alone exhibited catalepsy and significantly potentiated haloperidol-induced catalepsy (p<0.001). They also inhibited foot shock-induced aggression (p<0.001) in rats. Thus, both in-vivo and in-vitro studies confirm presence of antidopaminergic isoflavone in Butea monosperma flowers.
References: 1. Harborne JB. 1973. Phytochemical Methods.1st Ed. Toppan Company, Tokyo, Japan 53–59
2. Ferre, S. et al. (1990) Pharmacol. Biochem. Behav. 35:753–757
3. Datla, KP et al. (1992) Indian J. Exp. Biol. 30:587–591