Evaluation of Antidiabetic Activity of Carnosol (Phenolic Diterpene in Rosemary) in Streptozotocin-Induced Diabetic Rats

Background: Carnosol (CS) is an ortho-diphenolic diterpene in rosemary with great antioxidant potential. This study was designed to investigate the hypolipidemic, anti-oxidant, and anti-diabetic activities of CS. Methods: In our experiment, the rats were divided into the following groups of 8 animals each: control, untreated diabetic, three CS (1, 5, 10 mg/kg/day)-treated diabetic groups. On the first day of the study, the diabetic groups were given streptozotocin (STZ) in a single intraperitoneal (i.p.) injection at a dose of 60 mg/kg for induction of diabetes. CS was injected (i.p.) to the treatment groups from 3 days after STZ administration during a period of 4 weeks. At the end of the experimental period, we assessed the serum levels of glucose, IL-6, TNF-α, malondialdehyde (MDA), glutathione–s transferase (GST), superoxide dismutase (SOD), catalase (CAT) activities, triglycerides (TG), total cholesterol (TC), low density lipoprotein (LDL-C), and high density lipoprotein (HDL-C). Results: The results indicated that STZ caused an elevation of serum glucose, IL-6, TNF-α, MDA, TG, TC, LDL-C, and it also made a reduction of serum GST, SOD, CAT, and HDL-C (p<0.001). The findings showed amelioration in the serum glucose, IL-6, TNF-α, MDA, TG, TC, LDL-C, GST, SOD, CAT, and HDL-C in the CS-treated diabetic groups versus the untreated group, in a dose dependent manner (p < 0.001). Conclusion: In conclusion, the present investigation proposes that CS may be improved diabetes and its complications by modulation of oxidative stress and inflammatory responses.