The glycosylation and methylation of quercetin by cultured plant cells of Phytolacca americana gave quercetin 3-Ο-β-D-glucoside and isorharnnetin 3-Ο-β-D- glucoside. Myricetin was glycosylated and methylated to syringetin 3-Ο-β-D-glucoside by cultured P. americana cells.