Evaluation of Anticancer Activity of Lacto- and Natural Fermented Onion Cultivars

Abstract

The present investigation was carried out to evaluate anticancer and antibacterial activity of lacto- and natural fermented onions. The effect of the methanol extracts of lacto-fermented and natural fermented onions on MCF7 and peripheral blood mononuclear cells proliferation was measured using MTT assay at different concentrations (6.25, 12.5, 25, 50, 75, 100, 150, 200, 300, 350, 400, 450, 500 μg/ml). Two lactobacillus strains named Lactobacillus plantarum strains 1745 and 1058 were used in this study. The antibacterial activity of these extracts was also investigated against Staphylococcus saprophyticus, Proteus mirabilis, Escherichia coli and Streptococcus mutans. The best growth condition and lactic acid production for strains 1745 and 1058 were, respectively, achieved under aerobic and anaerobic conditions at 37 °C after 3 days. The highest level of lactic acid and acetic acid was also obtained in onions fermented by strains 1745. The lacto-fermented onion extracts in all species were found to have potent anticancer and antibacterial activity compared to natural fermented onions. In the present study, a good correlation has been shown between the flavonoid contents of onions and cytotoxic or antibacterial activity. Our data demonstrated that lacto-fermented onions might be good candidates against breast cancer cells.