相思樹葉子抽出物抗氧化活性之初探

Preliminary Investigation on the Antioxidant Activity of Extracts from the Leaves of Acacia Confusa

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

《中華林學季刊》 41卷2期 (2008/06) Pp. 249-263

https://doi.org/10.30064/QJCF.200806.0008

摘要

本研究利用1, 1-Diphenyl-2-picrylhydrazyl (DPPH)自由基清除活性、超氧自由基捕捉活性、抑制脂質過氧化、還原力與金屬螯合能力等抗氧化活性試驗，評估相思樹(Acacia confusa Merr.)葉子抽出物之抗氧化活性，並測定其總抗氧化能力、總酚類及總黃酮類含量。試驗結果顯示，甲醇抽出物之粗抽出物、乙酸乙酯可溶部及正丁醇可溶部的總酚類含量及總黃酮類含量均高，故能有效的清除DPPH自由基、清除超氧自由基、抑制脂質過氧化及還原過氧化物質，並具有良好的總抗氧化能力，其中，以乙酸乙酯可溶部之總酚類含量(307.8 mg of gallic acid equivalent/g)及總黃酮類含量(108.0 mg of quercetin equivalent/g)最高，故具有最強的清除DPPH自由基之效用(EC50=7.0μg/mL)、抑制脂質過氧化作用(EC50=110.0μg/mL)及還原過氧化物質之能力，其清除超氧自由基之作用(EC50=2.5μg/mL)甚至比已知之抗氧化劑兒茶素(EC50=7.0μg/mL)優異。此外，相思樹葉子熱水抽出物亦具有良好的清除DPPH自由基之效果及總抗氧化能力，其總酚類含量及總黃酮類含量則分別為254.7 mg of gallic acid equivalent/g及35.8 mg of quercetin equivalent/g。綜合試驗結果顯示，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 ； 葉子 ； 抽出物 ； 抗氧化活性 ； 總酚類含量 ； 黃酮類化合物

並列摘要

In this research, the antioxidant activity of extract from the leaves of Acacia confusa was evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical and superoxide radical scavenging assays, lipid peroxidation assay, reducing power and metal chelating ability on ferrous ions assays, and trolox equivalent antioxidant capacity (TEAC) assay. Total phenolic contents and total flavonoid contents were also evaluated. Antioxidant results of methanolic extract from A. confusa leaves revealed that the crude extract, EtOAc soluble fraction and BuOH soluble fraction possessed high amounts of total phenolic contents and total flavonoid contents, therefore these extracts exhibited great effectiveness in scavenging DPPH free radical, scavenging superoxide radical, inhibition of lipid peroxidation and reducing peroxidated substrates, and also have great TEAC. Among those extracts, EtOAc soluble fraction possesses the highest amount of total phenolic content (307.8 mg of GAE/g) and total flavonoid content (108.0 mg of QE/g), and demonstrated the great capacity of scavenging DPPH free radical (EC50=7.0μg/mL), inhibition of lipid peroxidation (EC50=110.0μg/mL) and reducing peroxidated substrates. Moreover, the scavenging of superoxide radical of EtOAc soluble fraction (EC50=2.5μg/mL) is more effective than catechin (EC50=7.0μg/mL). In addition, the hot-water extract of A. confusa also has great effectiveness in DPPH and TEAC assays, and it possesses high amounts of total phenolic contents (254.7 mg of GAE/g) and total flavonoid contents (35.8 mg of QE/g). The above-mentioned results obtained above indicated that the leaves of A. confusa have the potential to be used as a source for natural health products such as antioxidants.

並列關鍵字

Acacia confuse ； Leaves ； Extracts ； Antioxidant activity ； Total phenolic content ； Flavonoids