Cytotoxicity of Common Vegetable Oils and Fish Oils in the Australian Market; Good and Bad Oils

Abstract

Fat is an important part of the diet that provides the greatest amount of energy per gram of any food. Factors such as low saturated fatty acids, high unsaturated fatty acid and relatively low ω6/ω3 polyunsaturated fatty acid ratio have been associated with favorable health benefits. However it has been reported that certain vegetable oils have life shortening effects in experimental animals. We have recently reported a rapid bioassay-guided screening of bioactive substances in vegetable oils using cell lines instead of using time consuming animal experiments. This report details the fatty acid profile and biological activity of polar fractions of eighteen different types of vegetable oils and two fish oils available in the Australian market. Biological activity in the polar fractions of the oils were assessed on human embryonic kidney cells (HEK 293T). Fatty acid profile were analyzed by Gas Chromatography (GC). Polar fractions of fish oil (3.54% w/w) and canola oil (1.82% w/w) encountered the highest cytotoxicity: IC50=75µg/ml and 145µg/ml respectively, for HEK cells among the oils tested. Corresponding fractions of mustard, pumpkin, cod liver, sesame, avocado, almond, grape seed, soy, macadamia and apricot kernel oils showed moderate cytotoxicity IC50:180–440µg/ml. Polar fractions of peanut, wheat germ, olive, sunflower, flaxseed, safflower and coconut oils appears to be the safest (IC50>560µg/ml) for the HEK cells. Saturated fatty acids levels, ω6/ω3 ratios or amount of the polar fractions showed no correlation with the cytotoxicity of the polar fraction of the oils. The highest cytotoxicity of fish oil may be due to the formation of toxic compounds from oxidized oils due to the prolong storage or thermal processing of oils.