In the search for xanthine oxidase (XOD) inhibitors as anti‐gout agents from natural products, various chromatographic separations of the ethyl acetate‐soluble fraction of Aster glehni (AGEF) led to the isolation of five new caffeoylglucoside derivatives, namely 6′‐O‐caffeoyl‐(6S,9R)‐roseoside (1), 6′‐O‐caffeoylampelopsisionoside (2), 6′‐O‐caffeoylsonchuinoside C (3), 6′‐O‐caffeoyldihydrosyringin (4), and (2E)‐2‐methyl‐but‐2‐ene‐1,4‐diol‐6′‐O‐caffeoyl‐1‐O‐β‐glucopyranoside (glehnoside, 5), together with 13 known compounds. The absolute stereochemistry of the 6′‐O‐caffeoylsonchuinoside C (3) was established with the help of spectroscopic analyses, enzymatic hydrolysis, and Mosher's method, as well as in comparison with literature data. All isolated substances were determined for their inhibitory activities on uric acid production by the xanthine/XOD system. Among them, 4,5‐O‐dicaffeoylquinic acid methyl ester (12) showed the most potent inhibitory activity with an IC50 value of 2.6 ± 0.1 μM, which was comparable to that of allopurinol used as a positive control. Furthermore, hypouricemic effects of AGEF were assessed by measuring serum uric acid levels 3 h after potassium oxonate treatment (250 mg/kg, i.p.) to induce hyperuricemia in rats. When preadministered orally once a day at doses of 50, 100, and 300 mg/kg for 7 days, AGEF reduced the potassium oxonate‐induced elevated serum uric acid level by 15.4, 39.8, and 32.3%, respectively. The results suggest that AGEF has the potential to be a new source of agents for the prevention and/or treatment of hyperuricemia and gout.
在从天然产物中寻找黄嘌呤氧化酶(XOD)抑制剂作为抗痛风药物的过程中,对Aster glehni(AGEF)的乙酸乙酯可溶性馏分进行了各种色谱分离,分离出了5种新的咖啡酰葡萄糖苷衍生物,即6′-O-咖啡酰-(6S、9R)-roseoside (1)、6′-O-咖啡酰灯盏花苷 (2)、6′-O-咖啡酰松果菊苷 C (3)、6′-O-咖啡酰二氢紫丁香苷 (4)、和(2E)-2-甲基-丁-2-烯-1,4-二醇-6′-O-咖啡酰-1-O-β-吡喃葡萄糖苷(glehnoside,5),以及 13 种已知化合物。通过光谱分析、酶水解和莫舍尔法,以及与文献数据的比较,确定了 6′-O-咖啡酰松弛苷 C(3)的绝对立体化学性质。所有分离出的物质都被测定了对黄嘌呤/XOD 系统产生尿酸的抑制活性。其中,4,5-O-二咖啡酰奎宁酸甲酯(12)的抑制活性最强,IC50 值为 2.6 ± 0.1 μM,与作为阳性对照的别嘌醇的抑制活性相当。此外,在氧化钾(250 毫克/千克,静脉注射)诱导大鼠高尿酸血症后 3 小时,通过测量血清尿酸水平来评估 AGEF 的降尿酸作用。每天口服一次,剂量分别为 50、100 和 300 毫克/千克,连服 7 天后,AGEF 可使草酸钾引起的血清尿酸水平升高分别降低 15.4%、39.8% 和 32.3%。这些结果表明,AGEF 有可能成为预防和/或治疗高尿酸血症和痛风的新药源。