Saeed Mollaei - Phytochemical Laboratory, Department of Chemistry, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
Mina Mohammadi - Organic Laboratory, Department of Chemistry, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran

Oliveria decumbens Vent. (Apiaceae family) is an annual herb, and distributes in Syria, Iraq, south-east Anatolia, and Iran. In this study, the effect of acid pre-treatment before hydro-distillation was investigated on the yield and biological properties of the O. decumbens essential oil. Hydro-distillation method was used for the extraction of essential oils from the air-dried powdered flowers (۱۰ g) which were treated with acid solution. Then, the yield as well as antioxidant and insecticidal properties of the essential oils were calculated. The obtained results indicated that the pre-treatment with high acid concentration (۰.۶ mM HCl) increased the essential oil yield (۷.۱۶%) compared to the conventional method (۴.۴%). Acid solution could hydrolyze the cell walls, and then release secondary metabolites out of the cells. Also, carvacrol and thymol were the major constituents with up to ۶۰% obtained through both methods, and the acid pre-treatment could not change the amount of them, significantly. However, no significant changes were detected in the antioxidant and insecticidal properties of the essential oil, which were pretreated with ۰.۶ mM HCl, comparing to hydro-distillation method. Therefore, it may be suggested that if high yield is required, the O. decumbens flowers could be treated with acid solution.

Antioxidant, Essential oil, Oliveria decumbens, Pre-treatment