木豆叶提取物主要成分的抗氧化活性研究.doc

木豆叶提取物主要成分的抗氧化活性研究 摘要：用DPPH自由基清除法和β-胡萝卜素漂白法检测木豆叶的水提取物和乙醇提取物以及从乙醇提取物中分离的乙醚层组分，乙酸乙酯层组分，正丁醇层组分，水层组分和从乙醇提取物中分离出的四种主要化合物木豆素，球松素荭草荭草球松素β-胡萝卜素漂白法测试中，乙酸乙酯层组分（94.13%±3.41%）的抑制率是最高的，相当4mg/mlBHT（93.89%±1.45%）所达到的抑制效果。球松素荭草β-胡萝卜素 Antioxidant Activities of Extracts and Main Components of Pigeonpea [Cajanus cajan (L.) Millsp.] Leaves Abstract: Antioxidant activities of the aqueous and ethanol extracts of pigeonpea [Cajanus cajan (L.) Millsp] leaves, as well as petroleum ether, ethyl acetate, n-butanol and water fractions and the four main compounds separated from the ethanol extract, i.e. cajaninstilbene acid (3-hydroxy-4-prenylmethoxystilbene-2-carboxylic acid), pinostrobin,vitexin and orientin, were examined by a DPPH radical-scavenging assay and aβ-carotene-linoleic acid test. In the DPPH system, the antioxidant activity of the ethanol extracts was superior to that of the aqueous extracts, with IC50 values were 242.01 and404.91 μg/mL, respectively. Among the four fractions, the ethyl acetate one showed the highest scavenging activity, with an IC50 value of 194.98 μg/mL. Cajaninstilbene acid(302.12 μg/mL) and orientin (316.21 μg/mL) showed more efficient radical-scavenging abilities than pinostrobin and vitexin. In the β-carotene-linoleic acid test, the inhibition ratio (%) of the ethyl acetate fraction (94.13%±3.41%) was found to be the highest, being almost equal to the inhibition capacity of the positive control BHT (93.89%±1.45%) at 4 mg/mL. Pinostrobin (500 μg/mL) and vitexin (500 μg/mL) showed insignificant antioxidant activities compared with cajaninstilbene (321.53 μg/mL) and orientin (444.61μg/mL). In general, the ethyl acetate fraction of the ethanol extract showed greater activity than the main compounds in both systems, such results might be attributed to the synergistic effects of the components. The antioxidant activities of all the tested samples were concentration-dependent. Based on the results obtained, we can conclude that the pigeonpea leaf extracts may be v