A new flavanone with antifungal activity isolated from hops.

6-Isopentenylnaringenin 1, which has previously been synthesized by other workers, was isolated together with xanthohumol 2 and isoxanthohumol 3 from hard resins of hops (Humulus lupulus L.). The structures of 1 and sophoraflavanone B were examined; that of the latter previously reported as 6-isopentenylnaringenin, has been revised to 8-isopentenymaringenin. 1, 2 and 3 were found to have antifungal activities.