Potential Anti-Inflammatory, Hypoglycemic, and Hypolipidemic Activities of Alpha-Pinene in Diabetic Rats

Diabetes mellitus (DM) is a chronic disease characterised by high levels of glucose in the blood, resulting from a relative or absolute deficiency in the action of insulin. It is now clear that a state of chronic low-level inflam-mation is closely associated with the pathophysiology of DM, which may contribute to the long-term effects of the disease. Some monoterpenes, compounds present in oils from various aromatic plants, such as beta-pinene, have antidiabetic and anti-inflammatory properties. Thus, the current study sought to assess the hypoglycemic, hypolipidemic, and anti-inflammatory effects of alpha-pinene, an isomer of beta-pinene, in diabetic rats. Methods: Male Wistar rats (200-250 g) received a single injection of alloxan (40 mg/kg) through the penile vein to induce diabetes. Diabetic animals were orally treated with vehicle or alpha-pinene (25, 50, 100 mg/kg) or glibenclamide (5 mg/kg) for seven consecutive days. On the last day of treatment, blood samples were collected for biochemical analysis and the anti-inflammatory effect of alpha-pinene was evaluated using the carrageenan-induced paw edema and carrageenan-induced peritonitis models. Results: The treatment with the monoterpene decreased blood glucose, cholesterol, triglyceride, VLDL, LDL, HDL, AST and ALT levels when compared to the vehicle group. Likewise, the association alpha-pinene + glibenclamide also decreased blood glucose, total cholesterol and triglyc-eride levels. The oral treatment with alpha-pinene inhibited carrageenan-induced recruitment of total leukocytes to the peritoneal cavity and also inhibited carrageenan-induced paw edema. Alpha-pinene showed significant hy-poglycemic and hypolipemic activity at doses 25, 50 and 100 mg/kg. The strongest anti-inflammatory activity of alpha-pinene was observed at a dose of 50 mg/kg. Finally, these findings suggest that alpha-pinene may have anti-inflammatory, hypoglycemic, and hypolipemic properties. Its anti-inflammatory properties are probably an asset for the treatment of diabetes and its complications. However, new preclinical tests are required to elucidate the mechanism of action by which alpha-pinene exerts its activity.