ANTIOXIDANT ACTIVITY OF LAMIACEAE HERBS GROWNUNDER ORGANIC AND CONVENTIONAL FARMING

Lamiaceae herbs produce varieties of secondary metabolites which can be effectively used as food antioxidants. Antioxidant potential of selected widely used culinary herbs (two oregano species – Origanum vulgare L. and Origanum heracleoticum L. and spearmint Mentha spicata L.) from organic and conventional farming was therefore tested. Activity of aqueous extract was measured by using diphenylpicrylhydrazyl (DPPH) radical scavenging method, total phenolics content was determined by using the Folin-Ciocalteu reagent method. Antioxidant activity of both fresh and dried herbs was tested by the Schaal test based on the monitoring of the course of fat oxidation gravimetrically with free oxygen access in the dark at 60°C. Essential oils components which play an important role in antioxidant activity of herbs were determined by GC/MS analysis. Herbs from organic farming did not exhibit statistically significant higher antioxidant activity than those grown conventionally. Higher antioxidant activity of dried herbs aqueous extract than of extracts from fresh herbs was detected. The activity of herb extracts was different in hydrophilic and lipophilic matrices. Spearmint was the best antioxidant in an aqueous medium, while the effect of Greek oregano was ideal if fat containing medium was used. Its considerable antioxidant effect was because of high content of carvacrol and thymol in its essential oil