Antidiabetic effect of quercetin: A systematic review and meta-analysis of animal studies.

Quercetin is a plant polyphenol with biological activities such as anti-inflammatory, anticancer, antidiabetic, neuroprotective and anti-allergic. The objective of this review is to provide a systematic evaluation of the evidence and a meta-analysis of data from previously published researches on the antidiabetic action of quercetin. A comprehensive literature search was conducted between July 2018 and August 2018 on PubMed, EMBASE, Web of Sciences and Scopus databases. A random-effects model was used to estimate the pooled effect size and studies were weighted according to an estimate of the mean difference. The heterogeneity between studies was assessed using a Higgins' I2 test with corresponding p values. Overall 13 eligible articles with appropriate data on serum glucose were included in the statistical analysis. The meta-analysis for serum glucose level (mg/dL) showed that at doses of 10, 25 and 50 mg/kg there was a significant difference between the means. Therefore, the results of the meta-analysis support the hypothesis that quercetin lowers serum glucose level, at doses of 10, 25 and 50 mg/kg.