Xanthohumol from hop, a new all-rounder?
I will summarize the broad spectrum of biological activities of Xanthohumol (XN), a prenylated chalcone derived from hop (Humulus lupulus L.). In hop, the yellow compound is found in high quantities in the lupulin glands of the female inflorescence. XN is part of our diet mainly in the form of beer or beer mix drinks. Due to thermal conversion of XN to the isoflavanone isoxanthohumol during brewing, the concentration of XN in beer, however, is very low.
Hop not only adds bitterness and aroma to beer, but also plays an important role as a preservative. Although antibiotic properties are mostly attributed to hop bitter acids, various publications have described broad-spectrum anti-infective activities of XN against microorganisms including bacteria, viruses, fungi and malarial protozoa. Since the 1990s, interest in health-promoting effects of XN increased constantly. In 1997, XN was first shown to inhibit the activity of diacylglycerol acyltransferase involved in triglyceride synthesis. Recently, a potential influence of XN on fat metabolism was confirmed in vivo in a mouse model and explained by binding to the farnesoid X receptor, the physiological receptor for bile acids. XN was also described to inhibit bone resorption in vitro and might possess anti-osteoporotic properties.
In 2002, we identified XN as a potent cancer chemopreventive agent acting by multiple mechanisms relevant for the prevention of carcinogenesis. These include antioxidant effects, modulation of carcinogen metabolism, anti-inflammatory potential, estrogen antagonistic properties, anti-proliferative mechanisms by induction of apoptosis and cell differentiation, as well as anti-angiogenic and anti-invasive effects. Novel data indicate that XN prevents carcinogen-induced mammary carcinogenesis in rats and inhibits the growth of the breast tumor xenografts in SCID mice.
Future studies will further characterize the preventive and therapeutic potential of this interesting natural product.