ANTIOXIDANT ACTIVITY OF ORIGANUM MAJORANA L. HERB AND EXTRACTS OBTAINED BY SUPERCRITICAL CO_2 EXTRACTION

摘要

As the usage of synthetic antioxidants (e.g. butylated hydroxytoluene) is not approved in several developed countries, thus natural antioxidants have gained popularity in recent years. Among Lamiaceae plants many contain phenolic compounds which may lead the strong antioxidant activity. In this study, the antioxidant properties of marjoram (Origanum majorana L.) herb and extracts obtained by ethanol, n-hexane and supercritical CO_2 extraction are presented. Individual antioxidants (ursolic acid, carnosic acid and carnosol) were identified with high performance liquid chromatography. The effects of the parameters (temperature and pressure) of high pressure extraction on the yields of carnosol and ursolic acid were analysed. The effects of fractionation of extracts were followed at different extraction pressure. For screening the antioxidant activities of the herb aqueous and solvent extracts widely used analytical methods were applied. The free radical scavenging activities with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the total scavenger activity by chemiluminometric method were compared. From solvent extracts the antioxidant activity was performed using Rancimat method.