Isolation of a substance inducing apoptosis of cultured human gastric cancer cells from a hot-water extract of adzuki (Vigna angularis)

We have reported previously that treatment of KATO III cells, a human gastric cancer cell line, with hot-water extracts from adzuki beans inhibited their growth and induced apoptosis. This extract also suppressed benzo (a)pyrene-induced tumorigenesis in the forestomach of A/J mice. In the present study, this extract was chromatographed on an ODS column using H20-methanol as the eluent, and an apoptosis-inducing substance was purified by ODS-HPLC using the same eluent. Mass spectrometry and 1H-, 13C-NMR identified the apoptosis-inducing substance as catechin-7-omicron-beta-glucopyranoside (C7G). C7G suppressed the proliferation of both KATO III cells and HL-60 cells, but not that of normal cells. The DNA fragmentation induced by C7G was suppressed by N-acetyl-L-cysteine, implying that the antitumorigenic effect of the adzuki bean extract might be due to active oxygen-induced apoptosis.