Effect of quercetin glucosides from Allium extracts on HepG2, PC-3 and HT-29 cancer cell lines.

The present study investigated the effects of quercetin glucosides, which were isolated from the Chinese onion ( Allium chinense ), garlic ( Allium sativum ), onion ( Allium cepa L.) and the Welsh onion ( Allium fistulosum L.) in HepG2, HT-29 and PC-3 cancer cell lines. Quercetin-3,4'-di-O-glucoside (3,4'-Qdg) and quercetin-4'-O-glucoside (4'-Qmg) comprise ~98% of the flavonoids in the methanol extract of onion. A small amount of 3,4'-Qdg is present in the Welsh onion and Chinese onion, whereas 4'-Qmg is also present in the Welsh onion. In HepG2 cells, 4'-Qmg was demonstrated to exhibit more significant growth inhibition compared with 3,4'-Qdg and quercetin 3-β-D-glucoside, but exhibited less inhibitory effects in PC-3 and HT-29 cells. These results suggest the anti-proliferative potential of 4'-Qmg in various cancer cell lines and the health benefits of the genus Allium . The findings indicate the potential of 4'-Qmg as an anticancer agent for further development.