In vitro antioxidant and in vivo antidiabetic, antihyperlipidemic activity of linseed oil against streptozotocin‐induced toxicity in albino rats

Abstract The intake of omega‐3 unsaturated fatty acids has a beneficial effect on insulin sensitivity in rats and in subjects with type 2 diabetes. It has been reported that these omega‐3 fatty acids are useful in the treatment of hypertriglyceridemia and in the enhancement of high‐density lipoprotein (HDL)‐cholesterol levels in diabetic patients. The present study was therefore aimed to evaluate the antioxidant, antihyperglycemic and antihyperlipidemic effect of L. usitatissimum fixed oil. The antioxidant activity was evaluated in vitro using 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) and hydrogen peroxide (H 2 O 2 ) assay. The oil exhibited significant in vitro antioxidant activity in the DPPH and H 2 O 2 assay. The oil (1, 2, 3 mL/kg) was further investigated against streptozotocin (STZ)‐induced hyperglycemia and hyperlipidemia in albino rats, subjected to 3 weeks of treatment. The oil manifested decrease in blood glucose and glycated hemoglobin levels at higher dose and significant dose dependent negating action on antioxidant enzymes in the heart, liver and kidney tissues. The oil also normalized the various hematological parameters and electrolyte levels in the STZ treated rats. Treatment with oil significantly increased the level of serum HDL and decreased the levels of total cholesterol, triglycerides, and low‐density lipoprotein‐cholesterol in STZ‐diabetic rats in comparison to normal control. The antioxidant, antihyperglycemic and antihyperlipidemic activity of the oil could be attributed to the presence of linolenic acid (ALA, 18:3 n‐3) and its metabolic products, eicosapentanoic acid (EPA, 20:5 n‐3) and docosahexanoic acid (DHA, 22:6 n‐3).