金银花中酚酸类和黄酮类成分的黄嘌呤氧化酶抑制活性

Inhibitory activity of the flavonoids and phenolic acids from Jinyinhua on the xanthine oxidase

建立基于紫外分光光度原理的微孔板筛选方法,用于金银花药材中黄嘌呤氧化酶抑制剂的筛选,并进行抑制活性测定。通过对筛选条件优化,建立了可靠的筛选模型,并对从金银花中分离得到的20个单体化合物进行了筛选,发现8个酚酸类成分和4个黄酮类成分具有黄嘌呤氧化酶抑制活性,其中3,4-二咖啡酰奎宁酸甲酯、槲皮素和木犀草素有很好的活性,其IC50分别为8.36,6.46和2.08μmol/L。筛选结果表明,金银花中黄酮苷元的活性优于黄酮苷,双咖啡酰奎宁酸的活性明显优于单咖啡酰奎宁酸类成分,双咖啡酰奎宁酸甲酯的活性明显优于双咖啡酰奎宁酸,且双咖啡酰奎宁酸的5位取代对化合物的活性贡献最大。

The inhibitory effect on of xanthine oxidase was assayed by high-throughput microplate spectrophotom- eter in ultraviolet region and the developed method was used to screen the compounds separated from Jinyinhua. The in vitro high-throughput screening method for xanthine oxidase inhibitors was developed and optimized with four flavonoids and eight phenolic acids in Jinyinhua being discovered to have xanthine oxidase inhibitory activity. It was found that quercetin, luteolin and 3, 4-di-caffeoylquinic acid methyl had excellent activity and their IC50 values were 8.36, 6. 46 and 2. 08 μmol/L respectively. In the crude drug of Jinyinhua, the activity of flavonoid aglycones was better than that of flavonoid glycosides, and the activity of double caffeoyl quinic acids was better than that of single caffeoyl quin!c acids.Moreover, the activity of phenolic conjugates of methylated quinic acid was significantly better than that of quinic acid, and the 5-caffeoyl moiety contributed most to the activity of double caffeoyl quinic acids.