Flavonoid 6-O-methyltransferase involved in the biosynthesis of polymethoxylated flavonoids natural products such as nevadensin and salvigenin, aroma compounds which contribute to the flavor of sweet basil, and exhibit pharmacological activities such as anti-allergic, anti-oxidant, antibacterial, anti-proliferative, and anti-inflammatory effects. Catalyzes S-adenosylmethionine-dependent regioselective 6-O-methylation of flavonoids; active on various hydroxylated flavonoid substrates, including scutellarein-7-methyl ether (SCU7Me) and ladanein (LAD), and, with a lower efficiency, chrysoeriol (CHRYS) and cirsioliol (CIRL)