Neuropsychopharmacological profile of Astragalus membranaceous var. mongholicus

ObjectiveTo clarify the neuropharmacological profile of the Mongolian vetch, Astragalus mongholicus (Astragalus membranaceous var. mongholicus; synonym: A. mongholicus), extracts were evaluated for behavioral effects in rats and mice.MethodsAn aqueous extract of A. mongholicus was made by boiling roots from freshly-collected plants in 2.5 volumes (w/v) of water for 60 minutes. An ethanol extract was made by incubating in 70% ethanol for 5 days at 25°C. Effects of the aqueous extracts were evaluated in a forced swimming assessment of antidepressant effects, a hole-board test of exploratory behavior, an analysis of inhibition of aggression following electrical stimulation and influences on amnesia resulting from electroshock. Furthermore, effects of ethanol extracts of A. mongholicus were assessed on l-tryptophan induced twitches (indicating serotonin-mediated effects) and on hypothermia induced by apomorphine (indicating dopamine-mediated interactions) in mice.ResultsPer os (PO) administration of the aqueous decoction of the vetch to rats increased the response in a forced swimming test as reflected in wheel rotations. However, the decoction had no significant effect on the exploratory behavior of rats in the hole-board test. Acute PO administration of the aqueous extract of A. mongholicus decreased the threshold for aggressive behavior and this effect persisted with subchronic administration. Chronic administration of the plant extract suppressed aggression of rats. An ethanol extract of A. mongholicus showed an antiserotoninergic action and had a significant influence on the hypothermia induced by apomorphine.ConclusionA. mongholicus has a variety of potent psychotropic actions, suggesting influences on diverse neurotransmitter systems.