EVALUATION OF THE CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF THE PEEL OIL OF CITRUS NOBILIS

Peel oil of Citrus nobilis (Lour) was analyzed for determining its chemical composition. Fourteen identified components accounted for 99.1% (GC) and 100.0% (FID) of the total oil. Major component of the oil was limonene (76.8%-GC and 86.2%-FID). Essential oil was also evaluated for its antioxidant activity in four complementary test systems namely; beta-carotene/linoleic acid, DPPH radical scavenging, reducing power and metal chelating activities. In the first system, antioxidant activity increased with the increasing concentration. At 20.0 mg.ml(-1) concentration, antioxidant property of the oil was 96.8% +/- 0.2 and as strong as the positive controls BHT and alpha-tocopherol. Scavenging effect of the oil was superior to the positive controls BHT and alpha-tocopherol at 1.5 mg.ml(-1) concentration (96.4% +/- 0.1). Reducing power and chelating effect of the essential oil increased with the increasing concentration.