Black pepper (Piper nigrum) oleoresin has a neuroprotective effect on apoptosis induced by activity deprivation

Neuronal activity plays a key role in the development and maintenance of the central nervous system. In cultured cerebellar granule neurons (CGNs), activity deprivation by treatment with a low concentration of KCl induces neuronal apoptosis. We found that black pepper (Piper nigrum) oleoresin significantly increased the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide signal on activity-deprived CGNs, whereas piperine, a major compound in black pepper extract, did not. Consistently, induction of cleaved caspase-3, a hallmark of apoptosis was inhibited by black pepper oleoresin upon neuronal activity deprivation. These results show that black pepper oleoresin protects CGNs from apoptosis induced by activity deprivation, and suggest that components other than piperine might contribute to this effect.