Characterization of Antioxidants in Nutmeg {Myristica fragrans Houttuyn) Oil

摘要

Antioxidant capacity of nutmeg (Myristica fragrans Houttuyn) oil was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH') free radical scavenging assay and the β-carotene-linoleic acid assay. The antioxidant EC_(50) values of the crude nutmeg oil dissolved in methanol were 2.4 μL/mL and 0.4 μL/mL, respectively. The former value was approximately equivalent to the free radical scavenging capacities of 462 μM BHT and 656 μM a-tocopherol, and the latter one was comparable to the inhibitive capacities of 43 μM BHT and 9 μM α-tocopherol against the oxidation of β-carotene and linoleic acid. Further investigations discovered three major antioxidant constituents of the. nutmeg oil (i.e., eugenol, isoeugenol, and methoxyeugenol), which were sequentially separated and identified by silica open column chromatography, HPLC and GC-MS. Their antioxidant activities in the DPPH assay decreased in the following order: eugenol > methoxyeugenol > BHT > isoeugenol > a-tocopherol, while in the P-carotene-linoleic acid assay, the antioxidant activities of the chemicals were in the following order: a-tocopherol > BHT > isoeugenol > methoxyeugenol > eugenol.