Inhibitory Effects of Onion (Allium cepa L.) Extract on Proliferation of Cancer Cells and Adipocytes via Inhibiting Fatty Acid Synthase

Onions (Allium cepa L.) are widely used in the food industry for its nutritional and aromatic properties.Our studies showed that ethyl acetate extract of onion (EEO) had potent inhibitory effects on animal fatty acidsynthase (FAS), and could induce apoptosis in FAS over-expressing human breast cancer MDA-MB-231 cells.Furthermore, this apoptosis was accompanied by reduction of intracellular FAS activity and could be rescuedby 25 mM or 50 mM exogenous palmitic acids, the final product of FAS catalyzed synthesis. These resultssuggest that the apoptosis induced by EEO occurs via inhibition of FAS. We also found that EEO could suppresslipid accumulation during the differentiation of 3T3-L1 adipocytes, which was also related to its inhibition ofintracellular FAS activity. Since obesity is closely related to breast cancer and obese patients are at elevated riskof developing various cancers, these findings suggested that onion might be useful for preventing obesity-relatedmalignancy.