Antioxidant Activity of Constituents from the Methanolic Extract of Acacia confusa Leaves

相思樹葉子之抗氧化活性成分

林修賢(Shaw-Shien Lin) ； 蕭英倫(Ing-Luen Shiau) ； 張上鎮(Shang-Tzen Chang)

《台灣林業科學》 24卷1期 (2009/03) Pp. 61-68

https://doi.org/10.7075/TJFS.200903.0061

摘要

本研究首次利用不同in vitro試驗對相思樹葉子抽出物及其乙酸乙酯可溶部中分離得到的成分進行抗氧化活性體外試驗。由葉子抽出物中共分離鑑定出10種化合物，包括：3,4,5-trihydroxybenzoic acid methyl ester (1), 5,7,3',4'-tetrahydroxyl-flavone (2), myricetin 3-O-(3”-O-galloyl)-α-rhamnopyranoside (3), myricetin 3-O-(3”-O-galloyl)-α-rhamnopyranoside 7-methyl ether (4), myricetin 3-O-(2”-Ogalloyl)-α-rhamnopyranoside 7-methyl ether (5), myricetin-3-O-β-glucopyranoside (6), myricetin-3-O-α-rhamnopyranoside (7), myricetin 3-O-(2”-O-galloyl)-α-rhamnopyranoside (8), quercetin-3-O-α-rhamnopyranoside (9)和europetin-3-O-α-rhamnopyranoside (10)，此外，將10種化合物進行DPPH自由基、超氧自由基捕捉試驗及總抗氧化能力評估，並與標準品兒茶素做比較。在DPPH自由基捕捉試驗，除了化合物1與2，其他化合物之清除能力均較兒茶素(EC50=10.3 μM)強。總抗氧化能力方面，除了化合物1、6、9和10的總抗氧化能力稍差，其他化合物均較兒茶素(TEAC=3.49 mM)優異。另外，清除超氧自由基能力方面，除了化合物1、2、5及6較兒茶素(EC50=7.4 μM)差，其它化合物則與兒茶素相當。綜合上述結果，相思樹葉子抽出物頗具潛力開發為抗氧化之保健用品。

關鍵字

相思樹 ； 抗氧化活性 ； 成分 ； 葉子

並列摘要

In this study, the antioxidant activities of the leaf extract of Acacia confusa and constituents isolated from its ethyl acetate (EtOAc) fraction were investigated for the first time using various in vitro assays. Ten antioxidant compounds, namely, 3,4,5-trihydroxybenzoic acid methyl ester (1), 5,7,3',4'-tetrahydroxyl-flavone (2), myricetin 3-O-(3”-O-galloyl)-α-rhamnopyranoside (3), myricetin 3-O-(3”-O-galloyl)-α-rhamnopyranoside 7-methyl ether (4), myricetin 3-O-(2”-O-galloyl)-α-rhamnopyranoside 7-methyl ether (5), myricetin-3-O-β-glucopyranoside (6), myricetin-3-O-α-rhamnopyranoside (7), myricetin 3-O-(2”-O-galloyl)-α-rhamnopyranoside (8), quercetin-3-O-α-rhamnopyranoside (9), and europetin-3-O-α-rhamnopyranoside (10) were isolated and identified from the leaf extract. In addition, their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, superoxide radical-scavenging activity, and trolox equivalent antioxidant capacity (TEAC) were compared with catechin (as the positive control). As to the DPPH-scavenging activity, all compounds except for 1 and 2 displayed greater antioxidant capacities than catechin (EC50=10.3 μM), and all of their TEAC values were higher than that of catechin (3.49 mM of trolox) except for 1, 6, 9, and 10. In addition, all compounds except for 1, 2, 5, and 6, also expressed as high a superoxide radical scavenging activity as catechin (EC50=7.4 μM).

並列關鍵字

Acacia confuse ； antioxidant activity ； constituents ； leaves