Cytotoxicity of oxidised lipids in cultured colonal human intestinal cancer cells (caco-2 cells)

In this study, we investigated the extent of the cytotoxicity effect of oxidised lipids and whether tea catechins namely (−)epigallocatechin-3 gallate (EGCG) decreased lipid peroxidation in caco-2 cells. Cells treated with 0–100 μg/ml fish oil or methyl linoleate (ML) oxidised by UV irradiation for 24 h, 48 h and 72 h, indicated a substantial decrease in cell viability especially in samples treated with 100 μg/ml oxidised lipid. Addition of malondialdehyde (MDA) and hydroxynonenal (50 μM) also reduced cell viability. Using EGCG (50 μM) increased the viability of cells treated with 24 h oxidised mackerel oil (72% live and 28% dead) compared with 48 h oxidised mackerel oil (89% live and 11% dead) and 72 h oxidised mackerel oil (71% live and 29% dead) as monitored by the MTT assay. Apoptosis of caco-2 cells by oxidised fish oil and ML and protection by EGCG was confirmed using fluorescence microscopy and caspase-3 presence by Western blotting.