Dietary and environmental topoisomerase II poisons. A number of dietary and environmental compounds can act as topoisomerase II poisons. Included on the list of dietary natural products are: genistein (soy), EGCG [(−)-epigallocatechin gallate; green tea], sulforaphane (cruciferous vegetables), oleuropein (olives), curcumin (turmeric), thymoquinone (black seed). On the list of environmental chemicals are: 1,4-benzoquinone (benzene metabolite), PCB (polychlorinated biphenyl) quinone (industrial fluid), and NAPQI (N-acetyl-p-benzoquinone imine; acetaminophen metabolite).