Antioxidative Properties of Thymus pseudopulegioides: Comparison of Different Extracts and Essential Oils

Abstract

The ethanol (EE), acetone (AE), methanol (ME), hexane (HE), and water extracts (WE) of Thymus pseudopulegioides Klokov & Des.Shost (TPK) were assessed for their antioxidant activities. Antioxidant activities were evaluated by reduction of Mo(VI) to Mo(V), reducing power, linoleic acid peroxidation, superoxide scavenging activity, free radical-scavenging activity, metal chelating activity, hydrogen peroxide scavenging activity and peroxide scavenging activity and compared with alpha-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and trolox. Essential oils of TPK were characterized in total to be 27 components. TPK essential oil was found to contain thymol (20.62 %), germacrene D (9.84 %) and gamma-terpinene (8.36 %) as the major components. The WE was more potent antioxidant as a scavenger of peroxyl and super oxide radical than the other extracts. The AE (linoleic acid peroxidation, H O scavenging activity) and ME (reducing power, free 2 2 radical scavenging activity, metal scavenging activity) exhibited significant activities. Apparently, a relationship was found between the antioxidant potency and the phenolics (phenolic compounds, flavonoids and anthocyanins) in each extract. The ethanol extract has the highest total phenolics (4.164 mg gallic acid (GAE)/ g DW) and flavonoids (0.610 mg quercetin/g DW). Total anthocyanin of dried plant was also determined (0.661 mg/g DW).