ACETONIC EXTRACT FROM FEIJOA SELLOWIANA BERG.FRUITS INHIBITS PROLIFERATION, MODULATES BRUSH BORDERMEMBRANE ENZYMES ACTIVITIES AND PREVENT LIPID PEROXIDATIONIN HUMAN INTESTINAL EPITHELIAL CELLS

INTRODUCTION: Feijoa sellowiana fruits grow throughout the Mediterranean area and are used for human food. These fruits and especially the acetonic extract have been shown to possess biological activities, such as anti-cancer properties. AIMS & METHODS: We aim to investigate the effects of the acetonic extract of Feijoa sellowiana fruits on the viability, proliferation, brush border membrane enzyme activities and membrane lipid peroxidation of the human intestinal epithelial cells. Caco-2 cells were seeded into a 6-wells multiwells plate and cultured with appropriate medium. At confluence, cells were starvated for 24h and then exposed to the acetonic extract (500 ug/mL), for 24h. Lactase and sucrase activity, cell proliferation and viability were measured with the modified Dahlqvist method, bromodeoxyuridine incorporation assay and MTT vitality test, respectively. To test membrane lipid peroxidation we used the malondialdehyde (MDA) assay; for this purpose, cells were pre-treated with H2O2 (1 mM) for 2h, with H2O2for 2h and then the acetonic extract for 24h or with the acetonic extract for 2h and then H2O2 for 24h, respectively. Cells with medium alone were used as control. Data are expressed as mean±SD of 8 single experiments. RESULTS: Compared to control conditions, the acetonic extract significantly increased lactase activity (+7.1±1.0 fold increase vs control, p<0.05) and sucrase acivity (+3.2±0.7 fold increase vs control, p<0.05), significantly decreased proliferation (0.17±0.01 vs 0.23±0.01 l450−540; p<0.05) and had no effects on cells viability. Treatment of cells with H2O2alone induceda significant increase of the MDA levels (+2.3±0.3 fold increase vs control; p<0.05) that was not observed when the acetonic extract was added 2h after H2O2 (+1.3±0.5 fold increase vs control; p= NS). Also the pre-treatment of cells with the acetonic extractdid not induced a significant increase of the MDA levels (+1.5±0.4 fold increase vs control; p= NS). CONCLUSION: The treatment with the acetonic extract from Feijoa sellowiana fruits improves lactase and sucrase activity, inhibits cell proliferation, have no cytotoxic effects and prevent the H2O2-induced lipid peroxidation of human intestinal epithelial cells. These changes induced by the acetonic extract in the brush border enzyme activity may be exploited in case of enzymatic deficit of lactase and sucrase. Moreover, the observed anti-oxidant activity suggests a potential use of Feijoa as an adjuvant treatment of diseases related to oxidative stress.