夜香牛不同提取部位木犀草素的含量测定及体外抗氧化活性研究

Research on the content determination of luteolin from different extract fractions of vernonia cinerea and their antioxidant activities in vitro

目的比较夜香牛甲醇总提取物、石油醚部位、乙酸乙酯部位和水部位中木犀草素的含量,同时评价夜香牛不同提取部位的体外抗氧化活性。方法采用超声法提取夜香牛不同提取部位的木犀草素,采用高效液相色谱法(HPLC)分别测定其含量。以半数清除浓度(IC50)为体外抗氧化活性评价指标,对夜香牛不同提取部位进行1,1-二苯基-2-三硝基苯肼(DPPH)自由基和羟自由基的清除试验,并以维生素C(VitC)作为阳性对照。结果木犀草素在不同提取部位含量差异明显,不同提取部位的含量高低顺序依次为乙酸乙酯部位(1.0141mg/g)>正丁醇部位(0.7294mg/g)>甲醇总提取物(0.5702mg/g)>石油醚部位(0.2921mg/g),水部位检测不到木犀草素。不同提取部位体外抗氧化活性也有明显区别,其中乙酸乙酯部位的抗氧化活性最强,其DPPH自由基和羟自由基的IC50分别为(0.089±0.008)mg/mL和(1.484±0.252)mg/mL,两者分别与VitC的IC50比较,差异无统计学意义(P> 0.05)。结论夜香牛的乙酸乙酯部位木犀草素含量最高,并且体外抗氧化活性最强。

Objective To compare the contents of luteolin in methanol total extract, petroleum ether fraction, ethyl acetate fraction and water fraction of vernonia cinerea were compared, and to evaluate their antioxidant activities in vitro of different extract fractions of vernonia cinerea. Methods Luteolin from different extract fractions of vernonia cinerea were extracted by the ultrasonic method, and their contents were determined by the high performance liquid chromatography(HPLC) method. The inhibition tests of 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH) free radical and hydroxyl radical(HO·) were carried out in different extract fractions of vernonia cinerea with hemi-inhibitable concentration(IC50) as the evaluation index of antioxidant activity in vitro, and vitamin C(VitC) as the positive control. Results The contents of luteolin in different extract fractions were obviously different, and the order of contents in different fractions was ethyl acetate fraction(1.0141 mg/g) > n-butanol fraction(0.7294 mg/g) > methanol total extract(0.5702 mg/g) > petroleum ether fraction(0.2921 mg/g). However, luteolin could not be detected in water fraction. There were obvious differences in antioxidant activity in vitro among different extract fractions, among which ethyl acetate fraction had the strongest antioxidant activity, and the IC50 of DPPH free radical and HO· were(0.089±0.008) mg/mL and(1.484±0.252) mg/mL, respectively, and there were no statistically significant differences between each of them and IC50 of VitC(P > 0.05). Conclusion The content of luteolin in ethyl acetate fraction of vernonia cinerea was the highest, and its antioxidant activity in vitro was the strongest.