Anti-proliferative and total ERK1/2 inhibitory effects of plant flavonols on Human cervical cancer (HeLa) cells

Kaempferol, myricetin and quercetin are abundant flavonols in edible fruit and vegetables. Much previous data has shown the beneficial effects of these flavonols in cancer treatments. Thus, the cytotoxic effects on rhesus monkey kidney epithelial cells (LLC-MK2) and the anti-proliferative effects on human cervical cancer (HeLa) cells through total ERK protein expression of kaempferol, myricetin and quercetin have been investigated. The cytotoxic assay at 24h revealed the high safety of three flavonols on LLC-MK2 cells. Kaempferol (1-1000 µM) did not have any significant effect on the viability of these normal epithelial cells. The cytotoxicity of myricetin and quercetin was 5 µM and 50 µM, respectively. No flavonols could suppress total ERK1/2 protein expression in LLC-MK2 cells. In HeLa cells, kaempferol (5 µM) and quercetin (1 µM) significantly inhibited cell proliferations and total ERK1/2 protein expression. Myricetin significantly reduced cancer cell proliferations at 1 µM without any effect on total ERK1/2 protein expression. In conclusion, kaempferol and quercetin had an inhibitory effect on HeLa cells via reduction of total ERK1/2 protein at 24h. But the anti-proliferative effects of myricetin did not exert via total ERK1/2 protein expression. This study affirms the potency of three flavonols as future chemotherapeutic agents and herbal supplements.