Phenolic Content and Antioxidant Capacity of Essential Oil Obtained from Sawdust of Chamaecyparis obtusa by Microwave-Assisted Hydrodistillation

Abstract

Reactive oxygen species and free radicals play a major role in food deterioration. Current research is directed towards finding naturally occurring antioxidants of plant origin. In the present study, the chemical composition analysis of the essential oil obtained from sawdust of Chamaecyparis obtusa (COEO) was conducted by gas chromatography coupled with mass spectroscopy (GC-MS). Further, the phenolic content and antioxidant capacity of the COEO were investigated using different radical scavenging assays. The COEO obtained from the dried sawdust material using a microwave-assisted hydrodistillation technique resulted in the determination of 46 different compounds by GC-MS analysis, representing 98.94 % of total oil content. The COEO was characterised by the presence of mono- and sesquiterpene hydrocarbons, oxygenated mono- and sesquiterpenes, steroids, diterpenes and indole derivatives. At the highest tested concentration range, the COEO showed antioxidant capacity, i.e. the inhibition of DPPH, nitric oxide, superoxide and hydroxyl radicals of 80.16, 82.93, 72.99 and 71.62 %, respectively. Moreover, the COEO displayed concentration-dependent reducing power ability and remarkable inhibitory effect on ferric ion-induced lipid peroxidation in bovine brain extract. In addition, the COEO yielded (6.13±0.05) mg of gallic acid per g of dry mass. The present study confirms that the C. obtusa essential oil has potent antioxidant, lipid peroxidation inhibition and radical scavenging abilities; therefore, it might be used as a natural antioxidant to prevent food deterioration.

Keywords

• Chamaecyparis obtusa
• essential oil
• microwave extraction
• reactive oxygen species
• free radicals
• antioxidants