Nootropic effect of BR-16A (Mentat), a psychotropic herbal formulation, on cognitive deficits induced by prenatal undernutrition, postnatal environmental impoverishment and hypoxia in rats.

Subchronic administration of BR-16A (Mentat), a compound herbal formulation, and the nootropic agent, piracetam, augmented learning acquisition and retention of learning in normal rats, as well as in states of cognitive deficits induced by prenatal undernutrition, postnatal environmental impoverishment and sodium nitrite hypoxia. The test paradigms used were step-down latency in a passive avoidance test and transfer latency in elevated plus maze. The drugs were administered orally once daily for 7 days, behavioural testing being done 1 hr after the last administration on day 7. Post-trial performances of the rats at 24 hr and after another 7 days was assessed as indices of learning acquisition and retention of learning (memory), respectively. Mentat (100 mg/kg) and piracetam (100 mg/kg) induced statistically significant nootropic effect in all the test parameters. However, the lower dose (50 mg/kg) of Mentat did not significantly augment learning acquisition in normal rats and in induced states of cognitive deficits, but significantly improved retention of learning in normal rats and in animals with cognitive deficits. Acute single administration of either Mentat (100 mg/kg, orally) and piracetam (100 mg/kg, orally) did not exhibit any discernible nootropic effect in any of the paradigms or parameters investigated. The results indicate that Mentat, like piracetam, can facilitate learning and memory, and can be categorized as a nootropic agent. They also corroborate clinical reports on the memory-facilitative effect of Mentat and earlier experimental evidence of its nootropic activity in mice.