Inhibiting effects of epigallocatechin gallate (EGCG) on the formation of age pigment in vitro and in vivo

Lipofuscin age pigment is often considered as a hallmark of aging, which shows an accumulation rate inversely correlated with longevity and it is primarily composed of carbonyl-amino cross linked protein residues. The purpose of this study is to determine whether epigallocatechin gallate (EGCG) would inhibit the formation of age pigment in both MDA-modified human serum albumin and D-galactose-induced aging mice models by using spectrofluorometry, HPLC-PDA, FTIR spectrometer, SEM and TEM observation. Results showed that EGCG could inhibit the formation of age pigment in vitro and in vivo. The structure-activity relationship suggested that besides anti-oxidative stress and trapping the reactive unsaturated aldehydes, the inhibiting effects were correlated with the galloyl D-ring of tea catechins on neutralizing the amino-carbonyl cross-linking reaction.   Key words: Epigallocatechin gallate (EGCG), age pigment, galloyl group, amino-carbonyl cross-linking products.