Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Epigallocatechin Gallate (EGCG) Inhibits the Sulfation of 1-Naphthol in a Human Colon Carcinoma Cell Line, Caco-2
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2001 Volume 24 Issue 9 Pages 1076-1078


We have previously reported that epigallocatechin gallate (EGCG) strongly inhibits the in vitro phenol sulfotransferase (P-ST) activity of a human colon carcinoma cell line, Caco-2. In the present study, we examined the ability of EGCG to inhibit the sulfation of 1-naphthol in intact Caco-2 cells. Sulfation of 1-naphthol was detected in Caco-2 cells after 2 h of incubation, and was observed to continue for 24 h, resulting in an accumulation of sulfated 1-naphthol. Sulfation was strongly inhibited by the addition of EGCG to the culture medium. The IC50 of EGCG was calculated to be 20 μM; this value is similar to that obtained from in vitro assays (14 μM) [Ref. Tamura et al., Biol. Pharm. Bull., 23, 695, (2000)]. These results indicate that catechins are capable of inhibiting P-ST activity in intact cells as well as in vitro. We believe that the inhibitory activity of catechins might be the mechanism by which catechins (and green tea) exert anti-carcinogenic activity against procarcinogenic compounds that require P-ST activation in vivo.

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© 2001 The Pharmaceutical Society of Japan
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