Comparative Effects of Phytosterol Oxides and Cholesterol Oxides in Cultured Macrophage-Derived Cell Lines

The cytotoxicity of cholesterol and a mixture of β-sitosterol/campesterol (50%/40%) and their oxides was examined in a cultured-derived macrophage cell line, C57BL/6. Cell numbers, lactate dehydrogenase (LDH) leakage, protein content, lipid uptake, and mitochondria dehydrogenase activity were determined after exposure of cell mononlayers to sterols and sterol oxides at a concentration of 200 μg/mL for up to 120 h. Results indicate that the oxides of cholesterol, β-sitosterol, and campesterol exhibited similar patterns of toxicity as indicated by LDH leakage, cell viability, and mitochondria dehydrogenase activity. Greatest cell damage was associated with treatments containing 5α,6α-epoxide or cholesterol oxides, followed by β-sitosterol/campesterol oxides, cholesterol, and β-sitosterol. The oxides of β-sitosterol/campesterol caused less LDH leakage and less of an effect on protein content. Results of this study demonstrate that phytosterols contained in vegetable oils, when subjected to frying conditions, do oxidize and may cause cellular damage in an in vitro cell line similar to cholesterol oxides, although less severe. Keywords: Phytosterols; cholesterol; sterol oxides; macrophage