Humulus lupus (Hops)
A climbing perennial vine, the flowers of which are used as a flavoring agent in beer. Hops contains a range of flavonoids, including 8-prenylnaringenin – a potent phytoestrogen. Hops also exhibits chemopreventive activity, as an inhibitor of CYP1A1 – a liver (Phase I) enzyme that activates chemical carcinogens. Hops extract – in combination with valerian – has been studied as a sleep aid. Compounds isolated from hops also possess cytotoxic, anti-aromatase and antioxidant activities in-vitro, although in-vivo research remains to be done.