A comprehensive systematic review of the therapeutic effects and mechanisms of action of quercetin in sepsis

Sepsis is a life-threatening condition caused by a dysregulated host response to infection. Several studies have indicated that flavonoids exhibit a wide variety of biological actions including free radical scavenging and antioxidant activities. Quercetin, one of the most extensively distributed flavonoids in the vegetables and fruits, presents various biological activities including modulation of oxidative stress, anti-infectious, anti-inflammatory, and neuroprotective activities. The present systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements. We searched Web of Sciences, Google Scholar, PubMed, Scopus, and Embase databases up to February 2021 by using the relevant keywords. Out of 672 records screened, 35 articles met the study criteria. The evidence reviewed here indicates that quercetin supplementation may exert beneficial effects on sepsis by attenuating inflammation and oxidative stress, downregulating the mRNA expression of toll-like receptors (TLRs), modulating the immune response, and alleviating sepsis-related organ dysfunctions. Due to the promising therapeutic effects of quercetin on sepsis complications and the lack of clinical trials in this regard, future human randomized clinical trials are warranted.