((A-222)) (A-222) Effect of Quercetin on inflammatory markers in Diabetes mellitus: a systematic review and meta-analysis of animal studies

Background: Diabetes mellitus (DM) is a chronic metabolic disorder affecting tissues and organs, which can lead to more complications for the affected individuals. The development and progression of diabetes complications are strongly linked to inflammatory processes. Both pro-inflammatory cytokines, chemokines, and adhesion molecules play an important role in the development of diabetic complications. Quercetin, a flavonoid, is an effective inhibitor of lipoxygenases, exhibits anti-inflammatory, anti-oxidant, and immunomodulatory effects. However, limited evidence shows that Quercetin affects these parameters, with regard to anti-inflammation in diabetic conditions.

Objectives: To determine the effect of Quercetin on inflammatory markers in animal model of DM.

Methods: A comprehensive literature search was conducted without any date constraints using PubMed, Embase, Web of Science, and Google Scholar to select studies evaluating the effect of Quercetin on inflammatory markers focusing on IL (interleukin)-1β, IL-6 and tumour necrosis factor-α (TNF-α). Animal Studies on diabetic mice and rats were included for the analysis; however, in vitro, ex vivo, and non-rodent studies were excluded from the analysis. To determine the levels of inflammatory markers among the included studies, a meta-analysis was performed between animal models of diabetes with or without Quercetin intervention. A meta-analysis using a random-effects model (RE) was performed to calculate standardized mean differences (SMD) with 95% confidence intervals. Heterogeneity (I²), sensitivity analyses, risk of bias (SYRCLE tool), and publication bias (funnel plots, Egger’s test) were assessed.

Results: The systematic literature review and meta-analysis of 14 studies indicate that Quercetin treatment significantly reduces the IL- 1β (SMD: -1.57, 95% CI -2.65 to -0.49) (P = 0.004), IL-6 (SMD: -4.28, 95% CI -5.86 to -2.70) (P < 0.00001) and TNF-α (SMD: -3.40, 95% CI -5.17 to -1.63) (P = 0.0002). Possible publication bias and moderate-to-substantial heterogeneity were observed. The results were unchanged after the sensitivity analyses, trim-and-fill analyses, and the elimination of outlying studies.

Conclusions: This meta-analysis concludes that Quercetin treatment significantly reduces the inflammatory markers in diabetic animal models. These findings provide a strong preclinical foundation for further clinical research, highlighting Quercetin as a potential treatment to lower the inflammatory markers level in diabetic conditions.