Search for serine protease inhibitors from marine invertebrates.

在伊豆半岛、八条岛、九州和四国采集了海绵（273份）、腔肠动物（32份）、苔藓虫（7份）和被囊动物（26份）。样品的热甲醇萃取液在H_2O和CHCl_3之间进行分割，得到有机层和水层。测定每层对凝血酶和胰蛋白酶的抑制活性。海绵类45种，腔肠类5种，被囊类5种。一般在水层中发现活性，但一些有机层也有活性。提取一种海绵活性样品，提取提取液，经分离得到凝血酶抑制剂nazumamide a，其抑制凝血酶的IC_<50>为2.8 mug/mL。氨基酸分析和包括二维核磁共振和FABMS在内的光谱分析发现了一个具有n -2,5-二羟基苯甲酸末端的四肽(1)。另一种具有活性的海绵圆柱弓形虫经类似处理后，得到凝血酶抑制剂toxadocial a，其抑制凝血酶的IC_<50>为6.5 mug/mL。通过光谱分析和化学转化对其结构进行了解析，得到了一种不同寻常的四硫醛，如图2所示。

Marine sponges (273 samples), coelenterates (32 samples), bryozoans (7 samples) and tunicates (26 samples) were collected from the Izu Peninsula, Hachijo Island, Kyushu and Shikoku. The hot methanol extracts of samples were partitioned between H_2O and CHCl_3 to give organic and aqueous layers. Each layer was assayed for inhibitory activities against thrombin and trypsin. Forty-five samples of sponges, 5 of coelenterates and 5 of tunicates were active. Genrally, activities were found in the aqueous layers, but some organic layers showed activities.One of active sponge sample, Theonella swinhoei was extracted, and the extract was fractionated to obtain a thrombin inhibitor named nazumamide A, which inhibited thrombin at an IC_<50> of 2.8 mug/mL. Amino acids analysis and spectral analyses including 2D NMR and FABMS led to a tetrapeptide possessing the N-2,5-dihydroxybenzoate terminus (1).Another active sponge Toxadocia cylindrica was similarly processed to yield a thrombin inhibitor, toxadocial A, which inhibited thrombin at an IC_<50> of 6.5 mug/mL. The structure elucidation was carried out by means of spectral analyses and chemical transformation to obtain an unusual tetrasulfated aldehyde as shown (2)