Suppressive Effects of the Methanol Extracts from Soybean Products on SOS Response of Salmonella typhimurium Induced by Mutagens and Their Contents of Isoflavones.

Suppressive Effects of the Methanol Extracts from Miso on SOS Response of Salmonella typhimurium Induced by Mutagens and Their Isoflavone Contents.

“…However, the suppression was weak in the soybeans and their products had a lower content of these aglycons. Daidzein and genistein also suppressed the SOS response, but their glycosides did not (Kiyosawa et al, 1995). In the present study, among the miso groups, the increased aglycon content was not always correlated to the extent of suppression.…”

“…Furthermore, the antimutagenicity in the methanol extracts from miso and tempeh was strongly suppressed based on the SOS response of S. typhimurium induced by N-methyl-N'-nitrosoguanidine (MNNG), as compared with that ofthe soy products having a lower content of isoflavone aglycons (Kiyosawa et al, 1995).…”

“…Asahara et al (1992) have reported that 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2) was effectively bound to the strains of bacteria and yeast isolated from commercial miso, and their cell walls had antimutagenicity toward the mutagen based on the umu test with Salmonella typhimurium TA1535/pSKIOO2 (S. typhimurium). The hexane extracts from each commercial miso group have also been reported to exhibit a strong suppression on the mutagenesis of S. typhimurium TA 100toward benzoLa]pyrene and 3-amino-1,4-dimethyl-5H-pyrido [4,3-b J indole (Trp-P-I ), because of the antimutagenicity of unsaturated fatty acids such as olelc, Iinoleic and linolenic acids in the misos (Yamamoto et al, 1994).Furthermore, the antimutagenicity in the methanol extracts from miso and tempeh was strongly suppressed based on the SOS response of S. typhimurium induced by N-methyl-N'-nitrosoguanidine (MNNG), as compared with that ofthe soy products having a lower content of isoflavone aglycons (Kiyosawa et al, 1995).The present study was conducted in order to evaluate the suppressive effect of the methanol extracts from each group of commercial misos and miso preparations on the SOS response of S. typhimurium induced by a mutagen. The isoflavone contents of the methanol extracts were also deterrnined in order to determine any relationship with the suppressive effect among the miso groups.…”

“…For the preparation of the methanol extract from miso, l g of the lyophilized miso was added to 10 ml of methanol, and the mixture was stirred for I h in a refrigerator at about 5'C. After centrifuging the mixture at 18,000 rpm for 30 min, the supernatant was used for the umu test (Oda et a/, 1985).The percent suppression (%) of the SOS response was calculated as previously described (Kiyosawa et a/, 1995). Isoflavones in the methanol extract were deterrnined according to the method of Kitada et al (1986).…”

“…The percent suppression (%) of the SOS response was calculated as previously described (Kiyosawa et a/, 1995). Isoflavones in the methanol extract were deterrnined according to the method of Kitada et al (1986).…”