Abstract
Flavonoids represent a group of phytochemicals exhibiting a wide range of biological activities arising mainly from their antioxidant properties and ability to modulate several enzymes or cell receptors. Flavonoids have been recognized to exert anti-bacterial and anti-viral activity, anti-inflammatory, anti-angionic, analgesic, anti-allergic effects, hepatoprotective, cytostatic, apoptotic, estrogenic and anti-estrogenic properties.
However, not all flavonoids and their actions are necessarily beneficial. Some flavonoids have mutagenic and/or prooxidant effects and can also interfere with essential biochemical pathways.
Among the proteins that interact with flavonoids, cytochromes P450 (CYPs), monooxygenases metabolizing xenobiotics (e.g. drugs, carcinogens) and endogenous substrates (e.g. steroids), play a prominent role. Flavonoid compounds influence these enzymes in several ways: flavonoids induce the expression of several CYPs and modulate (inhibit or stimulate) their metabolic activity.
In addition, some CYPs participate in metabolism of flavonoids. Flavonoids enhance activation of carcinogens and/or influence the metabolism of drugs via induction of specific CYPs.
On the other hand, inhibition of CYPs involved in carcinogen