Antioxidant Activity of Extracts and Volatile Compositions of Steam Distilled Essential Oil and Super Carbon Dioxide Extracts from Nutmeg (Myristica fragrans H.)

Abstract

Seven extracts of nutmeg, including 1 essential oil using steam-distillation (SD), 3 extracts using supercritical carbon dioxide (SC-CO2) extraction at 3 different pressures (2000, 3000 and 4000 psi) and 3 solvent extracts using n-hexane, ethyl acetate and methanol, respectively, were obtained to evaluate their antioxidant properties. The antioxidant activities of these materials were determined and compared with antioxidants BHA and α-tocopherol in vitro using a ferric thiocyanate assay. The antioxidant properties of these extracts and antioxidants were determined as follows. BHA ＞ methanol ＞ ethyl acetate ＞ α-tocopherol ＞ n-hexane ＞ SC-CO2 3000 psi ＞ SD ＞ SC-CO2 4000 psi ＞ SC-CO2 2000 psi. In these extracts, the volatile compositions from the SC-CO2 and SD extracts were further identified by GC and GC/MS. The total concentration of phenolic compounds was found to be the highest in SC-CO2, 2000 psi extracts, while the lowest total concentration was found in the SD extracts. The highest concentration of monoterpenes was found in the SD extracts, while the lowest concentrations were found in the SC-CO2, 4000 psi extracts. These results suggest that the antioxidant activities of nutmeg extract by steam-distillation and SC-CO2 extraction were not only affected by the amounts of phenolic compounds but also the amounts of monoterpenes.