Volatile constituents and antioxidant activity of essential oils from Lippia multiflora Mold. growing in Gabon

Abstract The leaf essential oils from two samples of Lippia multiflora (Verbenaceae) collected in two localities of Gabon were obtained by hydrodistillation and analysed by GC and GC‐MS. The oils differed completely in their chemical composition: the former was characterized by a high amount of ipsdienone (54.6%), ( Z )‐ and ( E )‐ocimenones (20.3%); ( E )‐ β ‐farnesene (7.4%) and β ‐caryophyllene (4.6%) were the main components of the sesquiterpenoid fraction; the latter consisted mainly of thymol (41.9%), thymyl acetate (21.2%), p ‐cymene (9.8%) and carvacrol (7.2%), which allows differenciation between two chemotypes. The antioxidant and antiradical activities of both samples were evaluated comparatively to those of reference compounds (BHT, thymol and carvacrol). An interesting antioxidant activity was found for the second chemotype as expected on the basis of its phenolic compounds content. Copyright © 2004 John Wiley & Sons, Ltd.