Abstract: | The nerve tonic activity of Bacopa monniera has been attributed to two saponins named Bacosides A and B. In the present investigation, Bacosides A and a mixture of the two saponins were used as aqueous suspensions. In the shock motivated brightness discrimination reaction a single oral dose of 10 mg/kg, 90 min prior to training, significantly reduced the time per trial, increased the number of positive responses and enhanced the relearning index. Similar effects were also observed in the relearning trial, but it was necessary to give a second dose 90 min prior to testing. In the active conditioned avoidance test 10 mg/kg p.o. given every alternate day significantly reduced the reaction time from the day 4 onward as well as the number of days of training. In the conditioned taste aversion response the bacosides produced a significant decrease in the lithium chloride intake. This effect was dose related in the range of 2.5–7.5 mg/kg p.o. Bacosides appear to be promising compounds having facilitatory effect on mental retention capacity by improving responses with positive as well as negative reinforcement. |