In vitro radical scavenging activity of essential oils from Columbian plants and fractions from oregano (Origanum vulgare L.) essential oil

Antioxidant activities of essential oils from anise (Pimpinella anisum L.), fennel (Foeniculum vulgare Mill.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), oregano (Origanum vulgare L.), ylang-ylang (Cananga odorata Hook.), verbena (Lippia alba Mill.) and salvia negra (Lepechinia schiedeana (Schlecht) Vatke, syn. Stachys schiedeana Schlecht) were determined using the free radical alpha-alpha-diphenyl-beta-picrylhydrazyl (DPPH.) and the preformed radical monocation 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS(.+)). Some of the oils under investigation had antioxidant capacities in a range comparable to that of alpha-tocopherol, BHA, ascorbic acid and Trolox, which were used as reference antioxidants. The all-liquid chromatographic technique of multilayer coil countercurrent chromatography (MLCCC) was applied to the fractionation of oregano essential oil. For oregano, a high antioxidant activity was observed, which is mainly due to the presence of thymol and carvacrol in the essential oil. Copyright (C) 2002 John Wiley Sons, Ltd.