三叶人字草总黄酮的抗氧化作用评价

目的:评价三叶人字草总黄酮的抗氧化作用.方法:用75％乙醇提取结合聚酰胺纯化制备三叶人字草总黄酮,并采用紫外分光光度法对其总黄酮含量进行测定；以丁基羟基茴香醚(BHA),水溶性维生素E(Trolox)和柠檬酸作阳性对照,测定三叶人字草总黄酮清除1,1-二苯基-2-三硝基苯肼(DPPH·)、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS+·)、超氧阴离子和羟自由基的能力,以及对Fe3+和Cu2+的还原能力和对Fe2+和Cu2+络合能力,综合评价其抗氧化作用.结果:三叶人字草中总黄酮的含量为(3.26±0.36)％(n=3),具有清除自由基,且具有较好的还原能力和金属络合能力.其对DPPH·,ABTS+.、超氧阴离子和羟自由基、Fe3+还原、Cu2+还原、Fe2+络合以及Cu2+络合的IC50分别为7.84,2.384,26.48,1.878,24.67,7.67,77.67,70.15 mg·L-1,且均呈一定的量效依赖关系.结论:三叶人字草总黄酮具有较强的抗氧化作用.

Evaluation on Antioxidative Activity of Total Flavones of Kummerowia striata

Objective: To evaluate the antioxidative activity of total flavones of Kummerowia striata. Method: The total flavones of K. striata were extracted by 75% ethanol and purified by polyamide resin. And the contents of total flavones were measured. The antioxidative activity of total flavones of K. striata were analyzed by using different assays as 1,1-diphenyl-2-picryhydrozyl radica 12,2-diphenyl-1-(2,4,6-trintrophenyl) hydrazyl (DPPH) radical scavenging, diammonium 2,2'-agino-bis(3-ethylbenzothiazoline-6-salfonate(ABTS⁺) radical scavenging, superoxide radical scavenging, hydroxyl radical scavenging, reducing power and chelating ability, with the positive control of the antioxidative activity of butgl hydroxy anisd(BHA), trolox and citric acid. Result: The contents of total flavones of K. striata were (3.26±0.36)%(n=3),with strong free radical scavenging activity, effective reducing power and chelating ability. The IC₅₀ of inhibition for DPPH radical, ABTS⁺radical, superoxide radical, hydroxyl radical, reducing power (Fe³⁺), reducing power (Cu²⁺), chelating ability (Fe²⁺) and chelating ability (Cu²⁺) were 7.84,2.384,26.48,1.878,24.67,7.67,77.67,70.15 mg·L^-1 respectively. And all were related to the dose. Conclusion: The total flavones of K. striata has obvious antioxidative activity.