Y. Shirataki et al., Relationship between cytotoxic activity and radical intensity of isoflavones from Sophora species, ANTICANC R, 21(4A), 2001, pp. 2643-2648
Among 11 isoflavones tested, genistein [YS13] produced higher cytotoxic act
ivity against human oral tumor cell lines (HSC-2, HSG) than against normal
cells (human gingival fibroblast, HGF), suggesting its tumor-specific actio
n. Electron spin resonance (ESR) spectroscopy showed that YS13 did not prod
uce radical, nor scavenged O-2. (-), generated by hypoxanthine-xanthine oxi
dase reaction system, suggesting that radical-mediated oxidation mechanism
is not be involved in the YS13-induced cytotoxicity. Addition of one prenyl
group produced YS18 and YS19 with higher anti-Helicobacter pylori activity
. Addition of two prenyl groups produced YS21 with the highest cytotoxic ac
tivity but lower tumor-specificity. Since YS21 produced the highest amount
of radical and most efficiently scavenged O-2. (-), this compound may induc
e cytotoxicity by radical-mediated oxidation mechanism. All isoflavones fai
led to induce anti-human immunodeficiency virus (HIV) activity. These data
suggest the medicinal efficacy of isoflavones.