Baureithel K H, Büter K B, Engesser A, Burkard W, Schaffner W
Dept. of Pharmaceutical Biology, University of Basel, Switzerland.
Pharm Acta Helv. 1997 Jun;72(3):153-7. doi: 10.1016/s0031-6865(97)00002-2.
Flower extracts of Hypericum perforatum, Hypericum hirsutum, Hypericum patulum and Hypericum olympicum efficiently inhibited binding of [3H]flumazenil to rat brain benzodiazepine binding sites of the GABAA-receptor in vitro with IC50 values of 6.83, 6.97, 13.2 and 6.14 micrograms/ml, respectively. Single constituents of the extracts like hypericin, the flavones quercetin and luteolin, the glycosylated flavonoides rutin, hyperoside and quercitrin and the biflavone 13, II8-biapigenin did not inhibit binding up to concentrations of 1 microM. In contrast, amentoflavone revealed an IC50 = 14.9 +/- 1.9 nM on benzodiazepine binding in vitro. Comparative HPLC analyses of hypericin and amentoflavone in extracts of different Hypericum species revealed a possible correlation between the amentoflavone concentration and the inhibition of flumazenil binding. For hypericin no such correlation was observed. Our experimental data demonstrate that amentoflavone, in contrast to hypericin, presents a very active compound with regard to the inhibition of [3H]-flumazenil binding in vitro and thus might be involved in the antidepressant effects of Hypericum perforatum extracts.
贯叶连翘、毛金丝桃、金丝梅和奥林匹斯金丝桃的花提取物在体外能有效抑制[3H]氟马西尼与大鼠脑γ-氨基丁酸A受体（GABAA受体）苯二氮䓬结合位点的结合，IC50值分别为6.83、6.97、13.2和6.14微克/毫升。提取物的单一成分如金丝桃素、黄酮类化合物槲皮素和木犀草素、糖基化黄酮类化合物芦丁、金丝桃苷和槲皮苷以及双黄酮13,II8-双芹菜素在浓度高达1微摩尔时均不抑制结合。相比之下，穗花杉双黄酮在体外对苯二氮䓬结合的IC50 = 14.9±1.9纳摩尔。对不同金丝桃属植物提取物中金丝桃素和穗花杉双黄酮的比较高效液相色谱分析表明，穗花杉双黄酮浓度与氟马西尼结合抑制之间可能存在相关性。对于金丝桃素，未观察到这种相关性。我们的实验数据表明，与金丝桃素相比，穗花杉双黄酮在体外抑制[3H]氟马西尼结合方面是一种非常活跃的化合物，因此可能参与贯叶连翘提取物的抗抑郁作用。
