| Quercetin is a dietary flavonoid that can affect the balance between anti-oxidant defense system
and oxidative stress. A number of studies showed the positive effects of quercetin on diabetes
mellitus and related metabolic disorders through different pathways such as gut flora. However,
findings are conflicting. In addition, it seems no studies have summarized all potential mechanisms
of quercetin in diabetes mellitus, so far. Therefore, the aims of the present comprehensive review
were to provide an overview on biological and biochemical characteristics of quercetin and
investigate the effect of quercetin on diabetes mellitus and related metabolic disorders by focusing
on its effects on the modulation of gut microbiota. For this purpose, findings of In vitro, animal
studies, clinical trials, and review studies with the English language published until January 2021
were summarized. They were identified through electronic databases (PubMed, Scopus, and
Cochrane Library) and Google Scholar. Findings showed that quercetin can be an effective
component for improving glycemic status and other metabolic disorders related to diabetes mellitus
based on In vitro and animal studies. However, environmental factors, food processing and using
nanoformulations can affect its efficacy in human studies. Several potential mechanisms, including
the modulation of gut flora are proposed for its actions. However, due to limited clinical trials
and contradictory findings, more high-quality clinical trials are needed to make a decision on the
efficacy of supplementation with quercetin as a complementary therapy for the management of
diabetes mellitus, metabolic disorders, and modulating gut flora. |