Variation of the Chemical Composition of Essential Oils and Antioxidant Activity of Teucrium poliumL. Growing Wild in Jordan at Different Flowering Stages

Abstract

The composition of hydro-distilled oils of Teucrium polium L. at different stages (pre-flowering and flowering) was evaluated by Gas Chromatography/Mass Spectrometry (GC/MS). Furthermore, the antioxidant activity of the essential oils extracted from pre-flower and full-flower of T. polium was examined utilizing DPPH free radical scavenging and ABTS^.+ cation radical scavenging. The essential oils were analysis yielded 59 and 57 components, respectively. Oxygenated sesquiterpenes accounted for (49.90%) of the total amount in the fresh aerial portion at the pre-flower stage, followed by monoterpenes hydrocarbons (17.75%) and sesquiterpene hydrocarbons (8.00%). The majority of the fresh aerial portion at the full-flower stage portion was composed of oxygenated sesquiterpenes (45.71%) monoterpenes hydrocarbons (25.49%) and sesquiterpene hydrocarbons (12.14%). epi-α-Cadinol accounted for (11.90%) of the fresh plant at the pre-flower stage, followed by (E)-β-santalol (6.15%). After flowering, the concentrations of both components were dropped to (10.13%) and (5.14%), respectively. The results of the study indicate that T. polium has antioxidants in both the pre-flower and full-flower stages. Compared to the full-flowering sample, the pre-flowering essential oil showed greater antioxidant activity.