Pycnogenol (PYC) is a standardized extract from the French maritime pine bark that consists of a concentrate of polyphenols. The purpose of this study was to investigate the effect of PYC on the growth inhibition of HT29 colon adenocarcinoma cells and iNOS mRNA expression level. PYC treatment at 30μg/ml for 24 hr significantly induced the growth inhibition of HT29 cells. It was observed to occur in a dose-dependent manner. PYC treatment at 50 and 100μg/ml has inhibited HT29 cell growth by 83% and 98%, respectively. In estimation of iNOS mRNA expression level by RT-PCR, it was induced at 30μg/ml and increased by increment of PYC concentration. We assume that PYC treatment may, at least in part, attribute to induce iNOS to generate peroxynitrite (ONOO^⁣) resulting in the growth inhibition of HT29 cells.

Keywords: Pycnogenol, HT29, iNOS, Growth inhibition, Peroxynitrite (ONOO^⁣,)