Antimutagenic effects of a tea made from Actinidia arguta, sarunashi in Japanese, and its inhibitory effects on the formation of aberrant crypt foci induced by 1,2-dimethylhydrazine in mice.

Abstract

We previously determined the antimutagenic activity of the juice of Actinidia arguta (hereafter referred to as sarunashi-juice) using the Ames test. The anticarcinogenic effect of sarunashi-juice was observed in lung and skin tumorigenesis in mice. We hypothesized that tea prepared from the leaves and twigs of A. arguta (hereafter referred to as sarunashi-tea) might also have antimutagenic and anticarcinogenic properties. We investigated the antimutagenic activity of sarunashi-tea using the Ames test, and its preventive effects on the formation of aberrant crypt foci (ACF) induced by 1,2-dimethylhydrazine (DMH) in mice. Antimutagenic results against aflatoxin B1, benzo(a)pyrene (B(a)P), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and 1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridin-2-amine (PhIP) were observed with the administration of sarunashi-tea. The amounts of sarunashi-tea needed for 50% inhibition (ID50) toward B(a)P, MeIQx, and Trp-P-2 were 2.9, 2.5, and 6.3 times higher, respectively, than that of sarunashi-juice. The antimutagenic components present in the juice and tea prepared from sarunashi may be similar chemicals. However, the concentration of the antimutagenic substances may be 2.5–6.3 times lower in sarunashi-tea than in sarunashi-juice. The total number of ACF was significantly reduced in mice treated with DMH in the presence of sarunashi-tea compared to that in mice treated with DMH in the absence of sarunashi-tea. Further investigation of the mechanisms of antimutagenicity and anti-ACF formation and identification of active components in sarunashi-tea will be worthwhile.