Leaves of Eugenia brasiliensis Used as a Folk Medicine Contain Cyclooxygenase Enzyme and Lipid Peroxidation Inhibitory Compounds

Tea prepared from leaves of Eugenia brasiliensis has been used as a folk medicine in Brazil to alleviate inflammation and pain. In this study, tea and methanolic extract inhibited cyclooxygenase (COX-1 and -2) enzymes and lipid peroxidation (LPO). Therefore, bioassay-guided purification of methanolic extract was carried out and afforded a new lignan (aR,8S,8'R-7,8,7',8'-tetrahydro-8,8'-dimethyl-3,3'-dimethoxy-4,4'-dihydroxy-dibenzocyclooctadiene) and three known C-methylated flavonoids (stropopinin; demethoxymatteucinol; myrigalone G). All isolates at 37.5 mu g/mL inhibited COX enzymes, similar to aspirin and ibuprofen used as controls at 108 and 12 mu g/mL, respectively. Most of the isolates also showed strong LPO inhibition at 5 mu g/mL.