Behavioural studies on BR-16A (Mentat), a herbal psychotropic formulation.

The anxiolytic, antidepressant and anti-aggression activities of Mentat were investigated in rats and mice, using standard behavioural paradigms. Single acute administration of Mentat, up to a dose of 200 mg/kg, ip, induced insignificant behavioural effects on the test parameters. However, when Mentat was administered subchronically for 7 days at two dose levels (50 and 100 mg/kg, intragastrically), the drug induced dose-related behavioural effects. Thus, it exhibited anxiolytic effect, as assessed by paradigms like the open-field test and elevated plus-maze tests in mice, and the social interaction test and Vogel's drink conflict test in rats. Furthermore, Mentat attenuated the increase in rat brain tribulin, a putative endocoid marker of anxiety, levels induced by pentylenetetrazole (20 mg/kg, sc), a known anxiogenic agent. Mentat attenuated footshock-induced aggressive behaviour in paired rats but failed to affect clonidine-induced automutilative behaviour. The observed aggression-attenuating effect of Mentat may be related to its anxiolytic activity. Mentat exhibited significant antidepressant effect as indicated by its ability to reduce swim stress induced immobility in Porsolt's behavioural despair test, reduction in escape failures concomitant with an increase in avoidance response in the learned helplessness test, and attenuation of muricidal behaviour, in rats. The observed behavioural effects are consonant with the reported clinical utility of Mentat as an adjuvant in the treatment of anxiety and depression.