Piperine activates testicular apoptosis in adult rats.

Piperine, an alkaloid present in the fruits of commonly used spice pepper, is known to impair reproductive functions. In the present study, piperine was administered to adult male rats at the dose levels of 1, 10, and 100 mg/kg body weight for 30 days to evaluate its effects on the testis. A significant decrease in the activities of antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in the testis was observed at 10 and 100 mg of piperine administration when compared with the controls. A dose-dependent increase in lipid peroxidation and hydrogen peroxide generation was also observed. Sialic acid levels in the testis were also found to be decreased when piperine was administered at 10 and 100 mg dose levels. Immunofluorescence studies demonstrated a dose-dependent increase in caspase 3 and Fas protein in testicular germ cells after piperine treatment. These observations indicate that piperine induces oxidative stress and thereby triggers apoptosis in the testis, contributing to hampered reproductive functions. (c) 2008 Wiley Periodicals, Inc.