Five antioxidative phenolic acids were isolated from the leaves of oregano (Origanum vulgare L.). The structure of a new compound (5a) was determined to be 2-caffeoyloxy-3-[2-(4-hydroxybenzyl)-4, 5-dihydroxy]phenylpropionic acid on the basis of spectroscopic evidence. Especially, phenyl glucoside (1) and 5a showed an activity comparable to that of BHA.
