The in vitro antioxidant and antimicrobial activities of the essential oil and various extracts of Origanum syriacum L var bevanii

The present work examines the in vitro antioxidant and antimicrobial properties of the essential oil and various extracts from the herbal parts of Origanum syriacum L var bevanii. Polar subfractions of methanol extracts from both deodorised and non-deodorised materials showed the highest DPPH (2,2-diphenyl-l-picrylhydrazyl) radical-scavenging activity, with IC50 values of 21.40 and 26.98 (mu)g ml^-1 respectively, whereas the IC50 of the essential oil was 134.00 (mu)g ml-1. The antioxidant potential of the extracts appeared to be closely related to the presence of polar phenolics. However, the inhibitive effect on linoleic acid oxidation might be promoted by the presence of non-polar phenolics, as both hexane and dichloromethane extracts showed high antioxidant activities. The antimicrobial activity of the essential oil was superior to those of the other extracts. Nineteen compounds representing 962 g kg^-1 of the essential oil were identified; carvacrol (669 g kg^-1) was the main component. Overall, the results suggest that the essential oil and extracts from the herbal parts of O syriacum could be used as natural preservative ingredients in the food industry.