Although traditional therapies using  natural sources have been used for thousands of years, neither  the  active components nor  their molecular targets have been very well defined. Identification of the active chemical entities and molecular  targets of  these natural products is an active  area of research. Up to 70% of all drugs currently used for the treatment of cancer were derived from natural sources . In particular,  studies have shown that xanthohumol (XN; 2’,4’,6’,4-tetrahydroxy-3’-prenylchalcone),  a prenylated chalcone isolated from the hop plant (Humulus lupulus L.) (2) , inhibits the growth of different types of  human cancer cells,  including breast, colon, ovarian, and prostate cancer cells; leukemia cells; and  adipocytes (3-11) ,  and prevents the development of carcinogen-induced preneoplastic lesions in mouse mammary gland organ  culture (5) . Researchers also showed that this chalcone inhibits tumor cell invasion (12) angiogenesis (13) ,  and bone resorption (7).  XN has been shown to inhibit NF-kB activation I3, 14, suppresses the  activity of diacylglycerol acyltransferase which is involved in triglyceride synthesis (15, 16), downregulate  topoisomerase 1 (17) and  aromatase (18), and inhibit nitric oxide (19)   and prostaglandin E2 production (5). Additionally, others have described both caspase-dependent (3) and -independent (6)   activation of apoptosis by XN. Furthermore, this compound inhibits phase I  cytochrome P450 enzyme which is involved in metabolic activation of carcinogens (20) and induces phase II enzyme NAD(P)H:quinone reductase (21). XN was found to activate the famesoid X receptor (FXR) (22) ,  inhibits triglyceride  and  apolipoprotein B  secretion (23), and exhibits antidiabetic activity through the inhibition of lipid and glucose metabolism (22).

Xanthohumol is contained in the yellow pollen of the female hops flowers. It has anti-bacterial, anti-fungal, and anti-viral properties to protect the flowers, as part of the survival of the plant.