Characterization of Microwave Extracted Essential Oil from Taxus cuspidata Stem and Determination of Its Phenolic Content, Antioxidant and Free Radical Scavenging Activities

Abstract

This study was outlined to probe chemical composition, antioxidant and free radical scavenging activities of Taxus cuspidata stem essential oil (TCEO) using different antioxidant models followed by determination of its total phenolic content. The TCEO was obtained by hydrodistillation of stem material using a microwave-assisted extraction technique. Gas chromatography-Mass spectrometry analysis of the TCEO resulted in the determination of 87 different compounds, representing 92.3% of total oil. The oil contained monoand sesquiterpene hydrocarbons, oxygenated monoand sesquiterpenes, diterpenes, phenolics, hydroxy derivatives, steroids, indole derivatives, and fatty acids as its major constituents. The TCEO showed antioxidant capacity as the inhibition of DPPH radical by 92.8%. Also the TCEO had potent inhibitory effect on nitric oxide, superoxide, and hydroxyl radicals by 80.0%, 71.7%, and 73.7%, respectively. Moreover, the TCEO displayed concentration-dependent reducing power ability and remarkable ferric ion-induced lipid peroxidation inhibitory effect in bovine brain extract. In addition, the TCEO yielded 6.5 ± 0.5 mg GAE/g sample equivalent phenolic content. These findings confirm the biological efficacy of T. cuspidata stem as a potential source of natural antioxidant.