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.
It was recently shown that apigenin induces autophagy (a kind of cellular waste-recycling system) in leukemia cells, which may support a possible chemopreventive role, but that induction of autophagy simultaneously induces resistance against the chemotherapy drug vincristine. 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 prevent renal damage caused by cyclosporin in rats, associated with reduced expression of the cell death mediator bcl-2 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.
In vitro studies have shown that apigenin may be toxic to red blood cells.
Apigenin may also stimulate adult neurogenesis, with at least one study claiming that apigenin "stimulate[s] adult neurogenesis in vivo and in vitro, by promoting neuronal differentiation" and may be useful "for stimulating adult neurogenesis and for the treatment of neurological diseases, disorders and injuries, by stimulating the generation of neuronal cells in the adult brain." While potentially promising, the study used rats and its effects have yet to be demonstrated in humans. 
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^}Meyer, Hellen; Bolarinwa, Adrian; Wolfram, Guenther; Linseisen, Jakob (2006). "Bioavailability of Apigenin from Apiin-Rich Parsley in Humans". Annals of Nutrition and Metabolism50 (3): 167–72. doi:10.1159/000090736. PMID16407641.