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United States Department of Agriculture

Agricultural Research Service

Title: Characterization of volatile constituents of Origanum onites and their antifungal and antibacterical activity

Authors
item Altintas, Ayhan - ANADOLU UNIV-TURKEY
item Tabanca, Nurhayat
item Tyihak, Erno -
item Ott, Peter -
item Moricz, Agnes -
item Mincsovics, Emil -
item Wedge, David

Submitted to: Journal of Association of Official Analytical Chemists International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 8, 2013
Publication Date: December 2, 2013
Citation: Altintas, A., Tabanca, N., Tyihak, E., Ott, P.G., Moricz, A., Mincsovics, E., Wedge, D.E. 2013. Characterization of volatile constituents of Origanum onites and their antifungal and antibacterical activity. Journal of Association of Official Analytical Chemists International. 96(6):1200-1206.

Interpretive Summary: The genus Origanum is a main contributor to the oregano trade. Turkey has, in recent years, become a major supplier of Origanum herb and its oil to the world markets. Due to its high quality, the Turkish Origanum products are highly esteemed and preferred. Hydrodistillation or steam distillation are generally used for distillation of the essential oil from plant. The use of microwave energy in sample treatment has attracted growing interest in the past few years. The main objective of the present study was to investigate the chemical composition of microwave-assisted hydrodistilled oils and to compare them with classical hydrodistilled oils. Essential oils were subsequently evaluated for antimalarial, antibacterial, and antifungal activities. However, only antifungal activity was observed against the strawberry anthracnose-causing fungal plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides. Pure compounds, carvacrol and thymol were then evaluated for antifungal activity and only carvacrol demonstrated non-selective activity against the three Colletotrichum species.

Technical Abstract: Essential oils obtained by hydrodistillation (HD) and microwave-assisted hydrodistillaton (MWHD) of Origanum onites aerial parts were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). Thirty-one constituents representing 98.6% of the water distilled oil and fifty-two constituents representing 99.6% of the microwave-distilled oil were identified. Carvacrol (76.8% HD, 79.2% MHD) and thymol (4.7% HD, 4.4% MHD) were characterized as major constituents in both of the essential oils. Essential oils were evaluated for antimalarial, antibacterial, and antifungal activities. However, only antifungal activity was observed against the strawberry anthracnose-causing fungal plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides. Furthermore, carvacrol and thymol were then evaluated for antifungal activity and only carvacrol demonstrated non-selective activity against the three Colletotrichum species. Thymol and carvacrol were subsequently evaluated in a 96-well microdilution broth assay against Phomopsis obscurans, Fusarium oxysporum, three Colletotrichum species and Botrytis cinerea. No activity was observed against any of the three Colletotrichum species at or below 30 µM. However, thymol demonstared antifungal activity and produced 31.7% growth inhibition of P. obscurans at 120 hours, at 0.3 µM, whereas carvacrol appeared inactive. Thymol and carvacrol at 30 µM showed 51.5% and 36.9% growth inhibition of B. cinerea at 72 hours.

Last Modified: 12/19/2014
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