Antioxidant activity of oregano essential oil (Origanum vulgare L.)

Abstract

Essential oil obtained from oregano (Origanum vulgare L.) by Clevenger-type hydrodistillation and hydromodulus 1:10 m/v during 180 minutes, has been investigated in this work. Qualitative and quantitative composition of the oil was determined by GC-MS and GC-FID spectrometry. Antioxidant activity of the obtained oil was examined spectrophotometrically by DPPH test (after 20, 30, 45 and 60 minutes of incubation) and TBA-MDA assay. The yield of essential oil was 4.1 mL/100 g of plant material. Seven components were identified: α-thujene, myrcene, α-terpinene, o-cymene, γ-terpinene, thymol and carvacrol. The major components were thymol (45%) and carvacrol (37.4%). Oil incubated for 60 minutes has shown the best antioxidant activity according to DPPH test. The concentrations of essential oil, required for neutralization of 50% of initial DPPH radical concentration (EC50), were 0.761, 0.590, 0.360 and 0.326 mg/mL, after 20, 30, 45 and 60 minutes of incubation, respectively. Lipid peroxidation inhibition of 92.3% was achieved by 1.35 mg/mL essential oil concentration. The results obtained indicate that oregano essential oil is a good source of natural antioxidants with potential application in food and pharmaceutical industries, as a safer alternative to the synthetic antioxidants.

Keywords

• Origanum vulgare L.
• essential oil
• antioxidant activity
• GC-MS analysis