Search for Bioactive Marine Natural Products

海洋生物有50多万种。由于海洋生物所处的生存环境与陆地生物不同，海洋生物代谢产生的各种物质往往具有各种前所未有的化学结构和生物活性。为了从海洋生物中寻找新的生物活性物质，我们继续研究了在冲绳县和帕劳群岛的珊瑚礁中采集的几种海绵。从冲绳海绵Theonella swinhoei中分离得到5种具有生物活性的肽内酯，分别命名为Theonellapeptolides Ia、Ib、Ic、Id和Ie。这些肽内酯对L1210细胞具有细胞毒性，并对Na^+、K^+和Ca^++2具有离子迁移活性。从帕劳海绵Asteropussarasinosum中分离得到9个新的去甲羊毛甾烷-三萜低聚糖苷，分别为sarasinosides A_1、A_2、A_3、B_1、B_2、B_3、C_1、C_2和C_3。这些寡苷类化合物具有明显的鱼毒活性，抑制海星受精卵细胞分裂.从冲绳海绵Xestospongia sp.中分离得到9个新的大环生物碱，分别命名为araguspongines A-H和J。这些具有两个l-氧喹里西啶部分的生物碱表现出有效的血管舒张活性。

Marine organisms comprise over half a million species. Due to their unusual living environment as compared with terrestrial organisms, marine organisms metabolite and produce a variety of substances which often have various unprecedented chemical structures and biological activities. During the course of continuing studies in search of new biologically active substances from marine organisms, we have studied several marine sponges collected in the coral reef of Okinawa Prefecture and Palau Islands.1. Bioactive five lactones named theonellapeptolides Ia, Ib, Ic, Id, and Ie were isolated from the Okinawan marine sponge Theonella swinhoei and elucidated their absolute stereostructures by a new HPLC method for N-methly amino acids which was developed to analyze the amino acid composition of these peptide lactones. These peptide lactones are cytotoxic for L1210 cell and exhibit ionophoric activities to Na^+, K^+, and Ca^<++>2. Nine new norlanostane-triterpenoid oligoglycosides, sarasinosides A_1, A_2, A_3, B_1, B_2, B_3, C_1 C_2, and C_3 were isolated from the Palauan marine sponge Asteropus sarasinosum and their structures were determined. These oligoglycosides exhibit ichthyotoxic activity and inhibit cell division of fertilized eggs ofthe starfish.3. Nine novel macrocyclic alkaloids, araguspongines A-H, and J were isolated from an Okinawan marine sponge Xestospongia sp. and their absolute stereostructures were determined. These alkaloids having two l-oxaquinolizidine moieties exhibit potent vasodilative activity.