Morinda citrifolia（Rubiaceae）其俗名為Noni。本實驗以 80℃熱水、50 % 與99.5%酒精、乙酸乙酯及超臨界二氧化碳（SFE-CO2）等萃取條件，對海巴戟天之果實進行成分萃取，共得8種萃取物；依Trolox 當量的抗氧化能力、清除 DPPH自由基能力、清除超氧陰離子能力、清除氫氧自由基能力、清除過氧化氫能力以及螫合鐵能力等方法，進行抗氧化成分的分析，並將這些樣品進行總酚類含量測定，用以了解其抗氧化物質與總酚類含量之間的關係，結果顯示（a）乙酸乙酯所萃取的果實，其抗氧化能力與總酚類物質可能有關；（b）以50﹪酒精萃取的海巴戟天之果實比其他萃取方式具有較佳的總抗氧化能力（TEAC）與DPPH自由基供氫能力，並且抗氧化的特性較具多樣化，如具有顯著的清除氫氧自由基以及螯合鐵的能力，值得作為進一步純化抗氧化物質的方法。然而整體而言，海巴戟天之果實萃取物的抗氧化活性，皆比標準品差。 This study was conducted to evaluate the antioxidative activity of extracts from fruits of Noni (Morinda citrifolia). Hot (80℃) water, 50 % aqueous or absolute ethanol, ethyl acetate and supercritical fluid carbon dioxide（SF-CO2）were used as solvents to extract the effective components from fruits of Noni. The antioxidative activity of extracts was measured by Trolox equivalent antioxidant capacity (TEAC) assay, the scavenging ability of reactive oxygen species （superoxide ion, hydroxyl radical and hydrogen peroxides）and the chelating activity on ferrous ions. The amount of total phenols was also determined in the various extracts. Our findings indicate the following: (a) the antioxidant efficiency of the extract of ethyl acetate may be attributed to its phenolic content; and (b) the 50 % aqueous ethanol extract was exhibited various antioxidative activity, for example, showed higher TEAC, DPPH assay, the scavenging ability of hydroxyl radical and the chelating activity on ferrous ions. The 50 % aqueous ethanol extraction is preferably used as a method in the extraction of antioxidant. However, Noni fruits showed not the best antioxidative activities compared to standard.
