Antioxidant and antimicrobial activities of various solvent extracts, piperine and piperic acid from Piper nigrum

Black pepper (Piper nigrum L.) has long been regarded as a spice added to many foods and it is also considered as a medicinal plant. The predominant compound obtained from ethanolic extract of P. nigrum, the piperine, was purified and identified by HPLC, C-13 NMR and by FT-IR analysis. Piperic acid was synthesized by alkaline hydrolysis of the purified piperine. The antioxidant and the antibacterial activities of different solvent extracts from P. nigrum and purified piperine and piperic acid were determined by using various in vitro tests. In all ours experiments, synthesized piperic acid was found to have the highest antioxidant power and was the most effective with the minimum inhibitory concentration (<325 mu g/ml) against all strains tested. This comparative report indicates that these compounds, piperine and piperic acid, could be used as natural antioxidant and antibacterial agents in both food preservation and human health. (C) 2012 Elsevier Ltd. All rights reserved.