Antihyperglycemic and antihyperlipidemic effects of Cymbopogon citratus leaves in dexamethasone-induced diabetic rats

Abstract

Background: In sub-Saharan Africa, especially in Cameroon, different parts of Cymbopogon citrarus (C. citratus) are prescribed as remedies for diabetes mellitus and dyslipidemia. This study was designed to investigate the effects of hydroalcoholic extract of C. citratus (HACC) leaves in dexamethasone-induced-diabetic (Dex-db) rats. Materials and Methods: The HACC was obtained by decoction for 15 min by mixing 250 g of dry powder of the leaves of C. citratus by completing the total volume to 1L with a hydroalcoholic solution (water-ethanol, 30:70). After cooling to room temperature and filtration using Whatman No. 4 filter paper, the extract was concentrated using a rotary evaporator at 45 °C. Moderate diabetes was induced by daily subcutaneous injection of dexamethasone (5 mg/kg) once daily for 7 days. On the 8th day, the animals which have a blood glucose level greater than 120 mg/dL were selected and randomized into 5 groups of 5 animals each who received the different treatments for two weeks as follows: two negative control groups, negative normal control (NNC) and negative dexamethasone control (NDC) received only vehicle (distilled water); one positive control group received glibenclamide (5 mg/kg) and two groups received HACC at doses of 50 and 100 mg/kg respectively. On the other hand, compared to the NDC group, we observed a significant (P<0.001) dose-response after 14 days of treatment a decrease in serum concentrations of TC, LDLc, and AI, and an increase in HDLc. A highly significant decrease (P<0.001) was also observed in serum TG concentration but with a more pronounced action at the lowest dose of HACC (50 mg/kg). Results: After two weeks of administration of the HACC, we observed during the oral glucose tolerance test (OGTT) a highly significant rate of reduction in glycemia (%) at the two doses tested (50 and 100 mg/kg) compared to the NNC group (P<0.001) 2 hours after glucose load, no significant difference was observed (P>0.05). With regard to the serum lipid profile (total cholesterol (TC), HDL cholesterol (HDLc), triglycerides (TG), LDL cholesterol (LDLc) and atherogenicity index (AI)), after 14 days of administration of the various treatments, with the exception of the TC which decreased significantly (P<0.001), no significant difference (P>0.05) was observed on the other parameters in the animals having received the HACC only at the dose of 100 mg/kg compared to the NNC group. Conclusion: This finding suggests that the leaves of C. citratus have a highly significant antihyperglycemic and antihyperlipidemic activity in diabetic rats by preventing the postprandial glycemia peak and by readjusting the lipid profile, in particular by lowering serum LDL-cholesterol, triglycerides and the atherogenicity index.