General enzyme targets of quercetin and kaempferol

The general enzyme targets of quercetin and kaempferol represent a diverse group of proteins involved in critical cellular processes such as signal transduction, inflammation, and oxidative stress management (PMID: 27027332). These flavonoids are recognized for their ability to interact with and inhibit several key enzymes, most notably phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinases (MAPK), and various protein tyrosine kinases (PMID: 30746536). Beyond kinases, they also target enzymes like cyclooxygenase (COX-1 and COX-2) and lipoxygenase (LOX), which are central to the inflammatory response, as well as xanthine oxidase and topoisomerases (PMID: 18417135). By modulating these enzymatic activities, quercetin and kaempferol exhibit significant anti-cancer, anti-inflammatory, and cardioprotective properties in preclinical models (PubChem CID 5280343). However, their therapeutic application is complicated by low systemic bioavailability and the potential for drug-drug interactions due to their inhibitory effects on metabolic enzymes like Cytochrome P450 3A4 (CYP3A4) (PMID: 23673480). Their interaction typically involves competitive inhibition at the ATP-binding site of kinases or the active sites of metabolic enzymes, leading to altered signaling pathways and reduced production of inflammatory mediators.

Other names

Flavonoid-binding enzymesQuercetin-sensitive enzymesKaempferol-sensitive enzymesPolyphenolic enzyme targets

Quercetin and kaempferol primarily act as competitive inhibitors of ATP binding in various protein kinases, such as phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinases (MAPK) (PMID: 27027332). They also inhibit the activity of enzymes involved in the arachidonic acid cascade, including cyclooxygenase (COX) and lipoxygenase (LOX), thereby reducing the production of pro-inflammatory eicosanoids (PMID: 30746536). Additionally, they can modulate the activity of phase II detoxifying enzymes and antioxidant enzymes like xanthine oxidase (PMID: 18417135).