Effect of Olive Leaf Extract on glucose level among Diabetes-Induced Rats: A Systematic Review and Meta-analysis

Background This systematic review statistically analyzed Randomized Controlled Trials on Olive Leaf Extract (OLE) for effectiveness in managing glucose levels in diabetic rats. Methods Selected articles, with no date restriction in the search process, were assessed independently by the authors using SYRCLE’s risk of bias tool for animal studies. Comprehensive-Meta-analysis version 3.0 was used for data analysis. Findings from 8 trials that included 162 rats were reviewed. Result The findings revealed a significant increase in the insulin level, 4.83 μIU/mL SMD (Standardized Mean Difference), 95% CI, 2.13 to 7.54, and a reduction in blood glucose, from the combined random effects analysis of −4.21 mg/dl, 95% CI, −5.75 to −2.67. The secondary outcomes included significant reduction in total cholesterol and triglyceride levels with a forest plot showing hypolipidemic effect among the OLE treated rats as compared with the placebo groups, −6.32 mg/dl SMD (95% CI −9.75 to −2.88) and −4.22 mg/dl (95% CI −6.96 to −1.48) respectively. There was no statistical significant difference in body weight between the OLE treated rats and placebo groups, (0.46 gram SMD, 95% CI, −0.05 to 0.96, p = 0.98). Conclusion OLE is beneficial for both the lipid profile and glycemic control of diabetes induced rats and may be as effective among humans. The significant findings of this study The Olive Leaf Extract given to diabetes-induced rats caused a significant increase in the insulin level, and a decrease in glucose, triglyceride, and cholesterol levels; hence, OLE can be a promising alternative to control diabetes and its cardiovascular complications. This study adds This is the first systematic review and meta-analysis done on RCTs that determined the effect of Olive Leaf Extract on the Glucose and Insulin levels among diabetes-induced rats. It also analyzed the effect of OLE on triglyceride and cholesterol levels.