Anti‐Inflammatory and Anti‐Tumor‐Promoting Effects of 5‐Deprenyllupulonol C and Other Compounds from Hop (Humulus lupulus L.)

A new phloroglucinol derivative, 5-deprenyllupulonol C (1), along with four other phloroglucinol derivatives, 2–5, five chalcones, 6–10, four flavanones, 11–14, two flavonol glycosides, 15 and 16, and five triterpenoids, 17–21, were isolated from the female inflorescence pellet extracts of hop (Humulus lupulus L.). Upon evaluation of these compounds against the EpsteinBarr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, twelve compounds, i.e., 1–4, 11–14, 17–19, and 21, showed potent inhibitory effects on EBV-EA induction, with IC50 values in the range of 215–393 mol ratio/32 pmol TPA. In addition, eleven compounds, i.e., 1–4, 6, 11, 12, 14, 17, 18, and 20, were found to inhibit TPA-induced inflammation (1 μg/ear) in mice, with ID50 values in the range of 0.13–1.06 μmol per ear. Further, lupulone C (2) and 6-prenylnaringenin (14) exhibited inhibitory effects on skin-tumor promotion in an in vivo two-stage mouse-skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator and with TPA as promoter.