Anxiolytic effect of Echium amoenum in mice

Abstract Putative activity of hydroalcoholic and aqueous infusion extracts of Echium amoenum L. was investigated in mice using the rotarod model of motor coordination and the el evated plus m aze model of anxiety. The extracts were administered intraperitonealy (i.p.) once, one hour before performing the tests. Preliminary phytochemical study of the plant, with standard procedures, showed that it contains saponins, flavonoids, unsaturated terpenoids and sterols. There was no evidence of t anins, alkaloids and cyanogeni c glycosides. The hydroal coholic extract of Echium amoenum in the dose range employed (125, 250 and 500 mg/kg) had no significant effect on motor coordination while the aqueous extract (62.5, 125, 250 and 500 mg/kg) disrupted motor coordination signi ficantly. Intraperitoneal injection of aqueous extract (5, 10, 20, 30, 62.5, 80 and 125 mg/kg) showed a significant dose-dependent increas e in time spent in open arm (OAT) with no significant change in open arm entri es (OAE), closed arm entries (CAE) and total arm entries (TAE). The anxiolytic effect was most evident in 125 mg/kg group. It is almost evident that the extract produces its anxiolytic effect in the doses in which no change in motor activity is observable. Comparison of the dose response curve with the anxiolytic dose response of diazep am (0.25, 0.5, 1.0 and 2.0 mg/kg) in the same setting showed that the maximal effi cacy o f the extract is signi ficantly lower than di azep am. Becaus e o f di fferent maximal effi caci es we were not able to cal culate Extract/diazepam pot ency ratio but it does not seem to be more than 1/100. It is concluded that single administration of aqueous extract of Echium amoenum L. produces a signifi cant but mild to moderate anxiolytic effect