Piperine, a pungent alkaloid, is cytotoxic to cultured neurons from the embryonic rat brain.

The present study reveals that piperine, a pungent alkaloid present in various Piper species, is cytotoxic to cultured brain neurons. Exposure to piperine (12.5-100 microM) for 72 h caused a concentration-dependent reduction in the survival of primary cultured neurons from various regions of the embryonic rat brain under high density cell culture conditions. There were relative regional differences in the susceptibility to cytotoxic effects of piperine in which septum and hippocampus showed higher vulnerability among the eight regions. The primary cultures of septal and hippocampal neurons under low density cell culture condition were performed to evaluate the contribution of non-neuronal cells. The concentration-response profiles in both high and low density cell culture conditions were comparable (septum: EC50 = 43 and 27 microM, hippocampus: EC50 = 50 and 44 microM, under high and low density cell culture conditions, respectively) suggesting a minor role of non-neuronal cells on cytotoxicity of piperine to developing neurons.