A Comparative Study between Different Tunisian Propolis Essential Oils and Their Antioxidant Activities

Propolis is a resinous substance collected by bees from plants with a complex and variable chemical composition. Propolis and its fractions possess multiple biological activities. This study focused on a chemical and statistical comparison between four Tunisian Propolis Essential Oils (PEO) and their antioxidant activities. Volatile oils were extracted by hydrodistillation and analyzed by GC-MS. Essential oil yield varied from 0.095% to 0.324%. A total of 59 volatile components were identified mainly dominated by sesquiterpenes and diterpenes hydrocarbons. Six major components were found in all samples collected from the four different locations α-Cedrol, Manoyl Oxide, Manool, Totarol, Tricosane, and Eicosane. The antioxidant activities of Tunisian PEO have been evaluated using two methods: β-carotene-linoleic acid bleaching and DPPH radical scavenging assays and the results were compared with those of the standard antioxidant (Triolox). PEO from Bizerte region presented a lower IC50 value (30.5 μg/mL) than that of the standard antioxidant Trolox (IC50 = 40.05 μg/mL) indicating high antioxidant capacity using DPPH assay but for the β-carotene-linoleic acid bleaching assay, PEO from Zouarine region had the lowest value of IC50 (26.5 μg/mL) compared to the standard (IC50 = 31.25 μg/mL). Our findings demonstrated that PEO possess high antioxidant activities and may be suggested as a new potential source of natural antioxidant.