gms | German Medical Science

Background: To investigate potential inhibitory effects of epigallocatechin gallate (EGCG, a polyphenol in green tea), resveratrol (a polyphenol in red wine), and curcumin (a polyphenol in the spice Turmeric) on the proliferation of human retinal pigment epithelial (RPE) cells and to elucidate possible toxic side effects.

Methods: ARPE19 cells were cultured in the presence of various concentrations of EGCG, resveratrol, or curcumin, and compared to controls. The number of viable cells was measured after 24, 48, and 72 hours by flow cytometry. RPE cell proliferation (CFSE dilution assay), drug toxicity (Hoechst 33258), apoptosis (caspase 3/7 and 8), and VEGF (vascular endothelial growth factor) concentration in the supernatants (ELISA) were assessed.

Results: All 3 drugs inhibited RPE cell proliferation at all points in time with resveratrol being the most efficient and curcumin the least efficient. EGCG inhibited cell proliferation with intermediate efficiency, and showed the least induction of cell death. Resveratrol almost completely suppressed cell proliferation, and induced ARPE19 cell necrosis and caspase 3/7- and caspase 8-dependent apoptosis. Curcumin inhibited ARPE19 cell proliferation exclusively by induction of caspase 3/7- dependent but caspase 8-independent cell death and necrosis. In addition, EGCG, and even more so resveratrol, blocked VEGF production, but curcumin did not.

Conclusions: Resveratrol and, at lesser efficiency, EGCG inhibited ARPE19 cell proliferation, as opposed to curcumin. The inhibitory effect of EGCG was associated with less toxicity. Thus, both resveratrol and EGCG are potential candidates in the treatment of proliferative vitreoretinopathy or eye diseases induced by VEGF.