Wu Jyh-Horng, Tung Yu-Tang, Wang Sheng-Yang, Shyur Lie-Fen, Kuo Yueh-Hsiung, Chang Shang-Tzen
School of Forestry and Resource Conservation, National Taiwan University, Taipei 106, Taiwan.
J Agric Food Chem. 2005 Jul 27;53(15):5917-21. doi: 10.1021/jf050550m.
In the present study, the ethanolic extracts from the heartwood of Acacia confusa, a species indigenous to Taiwan, exhibit strong antioxidant effects. Among all the fractions from ethanolic extracts of heartwood, the EtOAc soluble fraction exhibits the best antioxidant activity. The 80% 1,1-diphenyl-2-picrylhydrazyl radical inhibitory activity by the EtOAc extract was observed at a concentration of 5 mug/mL, and at the same dosage there was a similar free radical scavenging activity for (-)-ascorbic acid and (+)-catechin, both of which are well-known antioxidants. In addition, the EtOAc extract also protects PhiX174 supercoiled DNA against strand scission induced by hydroxyl radical. Furthermore, following by column chromatography and reverse-phase high-performance liquid chromatorgrapy, 10 pure phenolic compounds, including three major antioxidants (3,7,8,3',4'-pentahydroxyflavone, 7,8,3',4'-tetrahydroxy-3-methoxyflavone, and 3,4,2',3',4'-pentahydroxy-trans-chalcone) and a new flavonoid (3,7,8,3'-tetrahydroxy-4'-methoxyflavone), were isolated from the ethanolic extracts of A. confusa heartwood.
在本研究中，台湾本土树种相思树心材的乙醇提取物表现出很强的抗氧化作用。在心材乙醇提取物的所有馏分中，乙酸乙酯可溶馏分表现出最佳的抗氧化活性。乙酸乙酯提取物在浓度为5微克/毫升时观察到对1,1-二苯基-2-苦基肼自由基有80%的抑制活性，在相同剂量下，其对（-）-抗坏血酸和（+）-儿茶素（两者均为著名的抗氧化剂）有类似的自由基清除活性。此外，乙酸乙酯提取物还能保护PhiX174超螺旋DNA免受羟基自由基诱导的链断裂。此外，通过柱色谱和反相高效液相色谱法，从相思树心材的乙醇提取物中分离出10种纯酚类化合物，包括三种主要抗氧化剂（3,7,8,3',4'-五羟基黄酮、7,8,3',4'-四羟基-3-甲氧基黄酮和3,4,2',3',4'-五羟基反式查耳酮）和一种新的黄酮类化合物（3,7,8,3'-四羟基-4'-甲氧基黄酮）。
