Involved in the biosynthesis of prenylated phenolics natural products which contribute to the bitter taste of beer and display broad biological activities (Probable). O-methyltransferase with a low substrate selectivity (PubMed:18223037). Methylates chalconaringenin, desmethylxanthohumol, xanthohumol, isoliquiritigenin, butein, 2',4-dihydroxychalcone, resveratrol, genistein and guaiacol (PubMed:18223037). Catalyzes the biosynthesis of 2',4'-dihydroxy-4,6'-dimethoxy-3'-prenylchalcone (4-O-methylxanthohumol) (PubMed:18223037). S-adenosyl-L-methionine + xanthohumol = 4-O-methylxanthohumol + H(+) + S-adenosyl-L-homocysteine desmethylxanthohumol + S-adenosyl-L-methionine = H(+) + S-adenosyl-L-homocysteine + xanthohumol isoliquiritigenin + S-adenosyl-L-methionine = 2'-O-methylisoliquiritigenin + S-adenosyl-L-homocysteine S-adenosyl-L-methionine + trans-resveratrol = 3-methoxy-4',5-dihydroxy-trans-stilbene + H(+) + S-adenosyl-L-homocysteine Inhibited by S-adenosyl homocysteine. Optimum pH is 8.5. Optimum temperature is 39 degrees Celsius. Secondary metabolite biosynthesis. Homodimer. Highly expressed in lupulin glands. Detected in cones, male flowers and roots. Belongs to the class I-like SAM-binding methyltransferase superfamily. Cation-independent O-methyltransferase family.