Apigenin

Apigenin (4’,5,7-trihydroxyflavone), found in many plants, is a natural product belonging to the flavone class that is the aglycone of several naturally-occurring glycosides. It is a yellow crystalline solid that has been used to dye wool. Apigenin may contribute to the chemopreventive action of vegetables and fruits. It was recently shown that apigenin induces a process called autophagia (a kind of cellular dormancy) that may well explain its chemopreventive properties, but at the same time it induces resistance against chemotherapy. Apigenin is a potent inhibitor of CYP2C9, an enzyme responsible for the metabolism of many pharmaceutical drugs in the body.

Apigenin has been shown to reverse the adverse effects of cyclosporin. Research has been conducted to study the effects of apigenin on reversal of cyclosporin-induced damage, and this was assessed by immunohistochemical estimation of expression of bcl-2, and estimation of apoptosis in histopathological sections. Cyclosporine A enhances the expression of transforming growth factor-β in the rat kidney, which signifies accelerated apoptosis. Therefore, transforming growth factor-β and apoptotic index may be used to assess apigenin and its effect on cyclosporine A-induced renal damage.

Apigenin acts as a monoamine transporter activator, one of the few chemicals demonstrated to possess this property. Apigenin is a ligand for central benzodiazepine receptors that competitively inhibited the binding of flunitrazepam with a Ki of 4&mu;M, exerting anxiolytic and slight sedative effects.

Glycosides
The naturally-occurring glycosides formed by the combination of apigenin with sugars include:


 * Apiin, isolated from parsley and celery
 * Apigetrin (apigenin-7-glucoside), found in dandelion coffee
 * Vitexin (apigenin-8-C-glucoside)
 * Isovitexin (apigenin-6-C-glucoside or homovitexin, saponaretin)
 * Rhoifolin (apigenin-7-O-neohesperidoside)
 * Schaftoside