What is "fisetin"

Fisetin \Fis"e*tin\, n. [G. fisettholz a species of fustic.] (Chem.) A yellow crystalline substance extracted from fustet, and regarded as its essential coloring principle; -- called also fisetic acid.

n. (context organic compound English) A particular flavonol, ''2-(3,4-dihydroxyphenyl)-3,7-dihydroxychromen-4-one'', found in several plants

Fisetin (3, 7, 3′, 4′-tetrahydroxyflavone) is a flavonol, a structurally distinct chemical substance that belongs to the flavonoid group of polyphenols. It can be found in many plants, where it serves as a colouring agent. It is also found in many fruits and vegetables, such as strawberries, apples, persimmons, onions and cucumbers. Its chemical formula was first described by Austrian chemist Josef Herzig in 1891.

The biological activity of fisetin has been studied in many laboratory assays; like other polyphenols it has many activities.