The roles of quercetin in diabetes mellitus and related metabolic disorders; special focus on the modulation of gut microbiota: A comprehensive review

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.

Iranian Salvia species: A phytochemical and pharmacological update

Salvia is the largest genus of the Lamiaceae family, with over 900 species in the world which about 60 species are distributed in Iran, 17 of them are endemic. In Iran, Salvia species have been used to treat various diseases with a wide spectrum of pharmacological activity in vitro and in vivo. The present review summarizes the phytochemistry and pharmacology of medicinal Iranian Salvia species in order to describe their therapeutic potential for a range of diseases. . Phytochemical investigations reveal that the Iranian Salvia has a varied range of metabolites including terpenoids, flavonoids and phenolic acids. The most important pharmacological activities are antidiabetic, antioxidant, antimicrobial, cytotoxic and anti-inflammatory. Iranian Salvia traditionally used as carminatives, analgesics, digestive aids, antiseptics, sedative, anxiolytic, hypnotic, pain reduction and antidiabetic. Among the endemic species, the most interesting for human health are treating a variety of diseases.