Fisetin

Fisetin is a flavonol, a type of flavonoid polyphenol, with the chemical name 3,3',4',7-tetrahydroxyflavone. It occurs naturally in a range of fruits and vegetables, most notably in strawberries, and is also found in apples, persimmons, onions, and cucumbers. In foods and dietary supplements, fisetin is typically present in modest amounts, but it has attracted attention for its bioactive properties.

Chemically, fisetin belongs to the flavonol subgroup of flavonoids and has a characteristic three-ring structure with four hydroxy groups. Its molecular formula is C15H10O6, and it exerts biological effects through multiple pathways, including antioxidant activity and modulation of signaling cascades involved in inflammation and cell survival.

In laboratory and animal studies, fisetin has shown antioxidant, anti-inflammatory, and anti-cancer activities, as well as neuroprotective and cardiometabolic effects in some models. It has also been investigated as a senolytic agent, capable of selectively clearing senescent cells in preclinical systems, a property of interest in aging research. However, human data are limited, and the clinical relevance of these effects remains to be established.

Pharmacokinetics and delivery are characterized by relatively low oral bioavailability, with rapid metabolism and conjugation to glucuronides or sulfates. This has prompted research into formulation strategies to improve absorption and tissue distribution, including nanoformulations and lipid-based carriers.

No medical indications have been approved for fisetin. It is sold as a dietary supplement in many regions, and dosing recommendations are not established in clinical trials. More robust human studies are needed to determine safety, efficacy, and potential therapeutic uses.