---

Chrysin

The flavonoids are a large group of secondary plant metabolites derived from flavan. Flavonoids are pigments found almost universally in plants. They are responsible for the coloration of the flowers, the fruits and sometimes the leaves. This is the case of the yellow flavonoids and red, blue or violet anthocyanosides. They can also contribute to coloration via their role as copigments: thus colorless flavones and flavonols copigment and protect anthocyanosides. The basic structure of the flavanoids is flavanone (flavan-4-one) from which the flavonoid derivatives flavonol (flavan-3-ol), flavone and flavonol are derived. The most widely occurring flavanoids are the flavones. Examples of flavones include apigenin, chrysin, eupatorin, fisetin, genistein, hesperitin, kaempherol, luteolin, morin, myricetin and quercetin. Chrysin (5,7-dihydroxyflavone) is a naturally-occurring flavone found in passion flower (Passiflora coerulea) extracts. Chrysin has activity as an anxiolytic agent, an anticonvulsant, an agent that reverses P-glycoprotein mediated multidrug resistance in human cancer cells, and as a protein kinase inhibitor. Myocardial infarction risk in elderly men is decreased by chrysin. Chrysin is believed to act by inhibiting aromatase, an enzyme responsible, inter alia, for converting testosterone to estrogen.

---