Frontier in Structure Elucidation of Natural Products

天然产物结构解析前沿

基本信息

批准号：
12045243
负责人：
MURATA Michio
金额：
$ 10.75万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Chemotaxis of sperm toward eggs during fertilization is a crucial event for species conservation, particularly for animals living in aquatic environments. Relevant chemical attractants have been found from a few marine organisms such as sea urchins and corals. We previously showed that sperm of the ascidian Ciona intestinalis is activated and then attracted toward the egg by a factor released from the egg, which led to the purification of sperm-activating and attracting factor (SAAF) from the egg-conditioning medium of Ciona intestinalis.The structure of SAAF was proposed to be a novel polyhydroxysterol sulfate on the basis of 2D-^1H NMR and FAB-MS/MS analysis using no more than approximately 4 microgram of a specimen. However, there still remained small but serious ambiguity that the biological activity might be attributed to a minor constituent. Synthesis is, therefore, essential for the unequivocal identification of SAAF as the active principle, and for the complete structure elucidation including the stereochemistry at C25. SAAF and its C-25 epimer were synthesized from chenodeoxycholic acid in 19 steps via the pivotal intermediate and both the sperm-activating and attracting activity of them were bioassayed. Synthetic SAAF activated the sperms of ascidian Ciona intestinalis at 3.7 nM and concurrently exhibited the attracting activity at<10 nM, which led to the unambiguous structure determination of SAAF and the verification of its dual activity. It is noteworthy that 25-epi-SAAF turned out to possess the comparative activities as those of SAAF.

受精过程中精子向卵的趋化性是物种保护的关键事件，尤其是在水生环境中的动物。已经发现了一些海胆和珊瑚等海洋生物的相关化学吸引剂。我们先前表明，卵子肠肠肠肠肠杆菌的精子被激活，然后通过鸡蛋中释放的因子吸引到鸡蛋，从而导致净化精子激活和吸引因子（SAAF）（SAAF）（SAAF）（SAAF）从ciona Intestinalis的卵形结构中使用SAAF的结构。标本的大约不超过4微克。但是，仍然存在很小但严重的歧义，即生物活性可能归因于次要成分。因此，合成对于将SAAF作为活性原理的明确鉴定以及完整结构阐明至关重要，包括C25处的立体化学。 SAAF及其C-25异构体是通过关键中间体从Chendoxyoxycholic合成的，并通过枢轴中间体进行了生物测定。合成SAAF在3.7 nm处激活了海腹肠肠的精子，并同时在<10 nm处表现出吸引活性，这导致了SAAF的明确结构的确定及其双重活性的验证。值得注意的是，25-EPI-SAAF的比较活动是SAAF的比较活动。