Anti‐Proliferative Effects of Selected Dietary Polyphenols on Human Colon Carcinoma Cell Line, T84

Abstract

Polyphenols are naturally occurring compounds in plants which are typically involved in defense against ultraviolet radiation or pathogens. Previous studies have shown that various polyphenols have anti‐proliferative properties in a variety of human cancers. The purpose of this study is to determine the effect of Quercetin (QC), Epigallocatechin‐3‐gallate (EGCG), Catechin and Resveratrol (RVL) on cell death and apoptosis in human colon carcinoma, T84, cells.Cell death and apoptosis was measured by using Annexin V: FITC Apoptosis Detection Kit I and a flow cytometry. Short term (1 hour) and long term (overnight; O/N) effects were observed. Cells were grown in 6 well plates, serum starved O/N and treated with different concentrations of polyphenols for varying time. Linear Sweep Voltammetry (LSV) was used to electrochemically characterize the antioxidant capacity and to quantify active RVL and QC (the polyphenols acting as reducing agents) for the time frame of the study.While EGCG and Catechin did not have an effect, RVL and QC showed an interesting dose and time‐dependent change in cell death and apoptosis. O/N exposure to 200 µM QC caused an increase in cell death and apoptosis (control: 5.5+ 1.0%; QC: 15.5+ 4.3%). However, 30 µM RVL increased cell death and apoptosis at 1 hr (control: 4.3+ 0.8; RVL: 13.9+ 3.2) and returned back to control levels with time. Based on LSV, QC has a higher antioxidant capacity than RVL. However, the antioxidant effect of RVL decreased over time. In summary, QC and RVL both have anti‐proliferative properties with QC having prolonged effects in human colon carcinoma cells. Thus, a combination of polyphenols might have a better effect in preventing colon cancer.