Anti-diabetic and anti-oxidative activity of fixed oil extracted from Ocimum sanctum L. leaves in diabetic rats

Ocimum sanctum L. (OS) leaves have been shown to exert diverse potential benefits in a variety of stress conditions. The present study was conducted to elucidate the effects of the fixed oil extracted from OS leaves on the blood glucose levels and serum lipid profile of streptozotocin-induced diabetic rats. In addition, the anti-oxidative activity of OS leaves to protect various organs including the liver, kidney and heart was investigated. The fixed oil of the OS leaves was extracted using hexane, and the various fatty acid contents of the oil were determined using gas chromatography-mass spectrometry. Male Wistar rats were allocated into three groups (n=7 per group): Normal control rats, diabetic rats and diabetic rats fed daily with the fixed oil for three weeks. The results showed that α-linolenic acid was the primary fatty acid contained in the fixed oil of OS. After 3 weeks of diabetic induction, the rats exhibited increased blood glucose levels and serum lipid profile, in addition to elevated serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatine kinase MB subunit (CK-MB), creatinine and blood urea nitrogen (BUN). The fixed oil significantly decreased the elevated levels of blood glucose, the serum lipid profile and the levels of serum creatinine and BUN (P<0.001), without exerting significant effects on the elevated serum levels of AST, ALT, LDH and CK-MB. Furthermore, the fixed oil increased the diabetically-reduced levels of serum insulin and decreased the rat kidney weight. Fixed oil suppressed the elevated thiobarbituric acid reactive substances (TBARS) level and increased the activity of various antioxidative enzymes in the rat renal tissue. By contrast, the fixed oil had no effect on the elevated TBARS level and the inhibited activity of the antioxidative enzymes in the rat liver and cardiac tissues. Histopathological results indicated that the fixed oil preserved the renal tissue against oxidative stress in diabetes. In summary, the results of the present study suggest that the fixed oil extracted from OS leaves exerted anti-hyperglycemic, anti-hyperlipidemic and free radical scavenging effects in diabetic rats, thus providing renal protection against diabetes. The α-linolenic acid contained in the fixed oil may be responsible for these effects.