Xanthohumol (14) and isoxanthohumol (6) derived from hop (Humulus lupulus L., Cannabaceae) and selected chalcone and chromene derivatives, obtained by chemical synthesis, were studied for antifeedant activity against the peach-potato aphid (Myzus persicae [Sulz.]). The study used also commercially available 4-chromanone (1), flavanone (4), naringenin (5), chromone (7), flavone (8), 7-aminoflavone (9), trans-chalcone (10), and 4-methoxychalcone (12). For chromone derivatives it was observed that the presence of a phenyl substituent at C-2 in the chromone (7) skeleton increased the insect antifeedant activity, and this activity was observed for a longer time. Also, the introduction of an amino group at C-7 of flavone (8) considerably increased the insect antifeedant activity, which was observed for the whole test time. Among the compounds examined, the strongest deterrents were isoxanthohumol (6), 7-methoxy-2,2-dimethylchroman-4-one (3), 7-aminoflavone (9), and 4-ethyl-4'-methoxychalcone (13).
