Comparison of antioxidant potential of volatile oils of Syzygium aromaticum and Illicium verum relative to conventionally used standards

The volatile oils of syzygium aromaticum linn. (cloves) and illicium verum hook. (star anise) were extracted by steam distillation. the antioxidant potential of these oils was evaluated by four methods: 1,1-diphenyl-2- picrylhydrazyl radical (dpph) free radical scavenging activity,total antioxidant activity,ferric reducing antioxidant power (frap) assay and ferric thiocyanate assay and total phenolics were also determined. the results revealed that scavenging potential of clove volatile oil was more than star anise volatile oil. the ic50 of the clove volatile oil was 4.56 ± 1.07 mg/ml while that of star anise was found to be 120 ± 1.80 mg/ml relative to butylated hydroxytoluene (bht),having ic50 of 12.1 ± 0.92 mg/ml. total antioxidant activity of clove volatile oil was also higher than star anise volatile oil. the frap values of clove and star anise volatile oils were 2830 ± 2.14 and 388 ± 1.32 μg of trolox equivalents (te) respectively. the total phenolic contents of clove and star anise volatile oils were 934.34 ± 1.6 and 85.36 ± 0.28 mg of gallic acid equivalents (gae)/g of volatile oil respectively. the inhibition of lipid peroxidation by clove volatile oil was found to be 66.63% ± 0.41 while that of star anise was 43.24% ± 0.48.