Functional mechanism of flavonoids in reducing hyperuricemia

Dietary plant chemicals - flavonoids

Flavonoids have a basic structure of two phenyl rings and one heterocyclic ring, and can be further classified into flavanols (e.g., catechins, gallatechins, and epicatechins), flavonoids (e.g., apigenin and luteolin), flavonols (e.g., quercetin and rutin), flavanones (e.g., naringin and hesperidin), anthocyanins (e.g., centaurin and anthocyanin), flavanols (e.g., naringin and hesperidin), and anthocyanins (e.g., centaurin and anthocyanin). Isoflavones (e.g. Genistein), etc.

In addition to the considerable benefits that have been found in humans (e.g., antioxidant, anti-aging, and anti-tumor activities), flavonoids have gained a lot of attention in recent years due to their anti-hyperuricemia and anti-gout activities. A large number of flavonoids inhibit XOD and ADA to reduce urate production, regulate renal urate transporters (URATl, GLUT9, ABCG 2, 0AT1, 0AT2, and 0AT3) to reverse urate excretion and reabsorption, and down-regulate pro-inflammatory cytokines (TNF-α, IL-Ι) β, PG-E2 and caspase 1) and inhibition of TLR4 / MyD88 signaling and NLRP-3 inflammasome activation.

Foods containing flavonoids

Some vegetables and fruits, including celery, citrus, lemon, and sour cherries, have been shown to inhibit key enzymes responsible for the formation of UA and its precursors (XOD and ADA), improve UA excretion in both the kidney and intestine, and inhibit UA reabsorption in proximal renal tubules. Citrus fruits contain a large number of bioactive compounds (such as vitamin C and various flavonoids) and according to many reports have potential anticancer, antioxidant, and antimicrobial activities. Previous studies have shown that four citrus species exhibit XOD inhibitory activity in vitro. The potassium citrate contained in lemon can regulate the mRNA expression of human kidney ABCG 2 and GLUT 9. Sour cherries, also known as sour cherries, have a strange astringent taste compared to sweet cherries. HUA rat model revealed that 0.17g/kg dose of sour cherry powder can reduce ADA activity against HUA. In addition, 21 tart cherry species have been reported to have XOD inhibitory activity in vitro.

Hyperuricemia is regulated by flavonoids

Epigallocatechin-3-gallate has been reported to inhibit XOD and ADA and down-regulate renal urate reabsorption transporters GLUT9 and URAT 1. Similarly, three flavanols (theaflavin, theaflavin-3-gallate, and flavin-3, 3 '-digallate) extracted from black tea showed XOD and ADA inhibitory activity and the regulatory activity of urate transporters (GLUT9, URAT 1, OAT 1, OAT 2, and ABCG 2). Quercetin, a flavonol widely found in vegetables and fruits, can inhibit XOD, down-regulate GLUT9 and URAT 1, and up-regulate OAT 1. Rutin, another flavonol, also inhibited XOD in HUA mice. In addition, flavanols (such as taxasin and astilbin) and isoflavones (such as genistein) also have in vivo XOD inhibitory activity. Anthocyanins are water-soluble natural pigments that are abundant in colorful vegetables and fruits. According to in vivo studies, anthocyanins have demonstrated anti-hyperuricemia effects by inhibiting hepatic XOD and regulating the expression of renal urate transporters (URATl, GLUT9, ABCG 2, 0AT1 and 0AT3).

In conclusion, phytochemicals extracted from natural plants provide an effective method for the regulation of high serum uric acid. The prevention and treatment of hyperuricemia is a complicated process involving multiple channels and targets. Therefore, the integrated, multitargeted, and multifactorial action of phytochemicals may be critical for reducing high serum uric acid levels, dissolving sodium urate crystals, and combating hyperuricemia. Extensive research has shown that edible plants, including vegetables, fruits, and herbs, can be used as dietary uric acid lowering supplements. In addition, phytochemicals derived from natural plants, such as flavonoids, have advantages in terms of concentration, convenience, standardization, targeted benefits, and enhanced bioavailability.