Flavonoids in Rosmarinus officinalis leaves.

Three new flavonoid glucuronides, luteolin 3'-O-beta-D-glucuronide, luteolin 3'-O-(4"-O-acetyl)-beta-D-glucuronide, and luteolin 3'-O-(3"-O-acetyl)-beta-D-glucuronide, together with hesperidin, were isolated from 50% aqueous MeOH extract of the leaves of rosemary. The structures were established by chemical and spectroscopic methods. Their antioxidant activities were evaluated by a ferric thiocyanate method with hesperidin showing the greatest activity.