Kong L D, Wolfender J L, Cheng C H, Hostettmann K, Tan R X
Planta Med. 1999 Dec;65(8):744-6. doi: 10.1055/s-2006-960854.
Xanthine oxidase is a key enzyme associated with the incidence of hyperuricemia-related disorders. Repeated chromatography of the enzyme inhibitory part of the water extract of the twigs and leaves of Brandisia hancei (Scrophulariaceae) gave a flavone luteolin, an iridoid glycoside mussaenoside, two beta-sitosterol glycosides daucosterol and beta-sitosterol gentiobioside, and five phenylethanoids arenarioside, brandioside, acteoside, 2'-O-acetylacteoside and isoacteoside. Luteolin and isoacteoside inhibited the xanthine oxidase (XO, EC 1.2.3.2) with the IC50 values at 7.83 and 45.48 microM, respectively. Isoacteoside was found to be the first phenylethanoid that decreased substantially the formation of uric acid by inhibiting competitively xanthine oxidase (Ki value: 10.08 microM). Furthermore, the study suggested that the caffeoylation of the 6'-hydroxyl group of the phenylethanoids was essential for the enzyme inhibitory action.
黄嘌呤氧化酶是一种与高尿酸血症相关疾病发病率相关的关键酶。对玄参科植物长叶阴行草嫩枝和叶片水提取物的酶抑制部分进行反复色谱分离，得到黄酮类化合物木犀草素、环烯醚萜苷莫桑苷、两种β-谷甾醇苷胡萝卜苷和β-谷甾醇龙胆二糖苷，以及五种苯乙醇苷阿雷纳苷、阴行草苷、毛蕊花糖苷、2'-O-乙酰毛蕊花糖苷和异毛蕊花糖苷。木犀草素和异毛蕊花糖苷对黄嘌呤氧化酶（XO，EC 1.2.3.2）有抑制作用，IC50值分别为7.83和45.48微摩尔。发现异毛蕊花糖苷是第一种通过竞争性抑制黄嘌呤氧化酶（Ki值：10.08微摩尔）而显著降低尿酸形成的苯乙醇苷。此外，该研究表明苯乙醇苷6'-羟基的咖啡酰化对于酶抑制作用至关重要。
