Bioactive Constituents Of Marine Sponge Haliclona Oculata And Plakortis Simplex

Marine sponges, the oldest and simplest multicellular animals widely spreading on earth, have been proved to be a particularly fruitful source of new compounds with novel structures and bioactivities because of its special environment and its lifestyle. During the course of searching for novel secondary metabolites from marine organisms collected from the South China Sea, we encountered the sponge Haliclona oculata and Plakortis simplex collected from Yongxing island, Xisha, China. The crude extract of the two sponge show significant activity against human cancer cell lines. So we think it is worth investigating the constituents of these two sponges.The sponge Haliclona oculata belongs to class Demospongiae, order Haplosclerida and family Haliclonidae. Guided by bioassay method, the crude extracts were separated employing solvent partitioning followed by various chromatographic methods including VLC, LPLC, MPLC, HPLC on silica gel column, ODS RP C18 and Sephadex LH-20 to afford 12 compounds. Structures of 9 compounds were elucidated on the basis of extensive spectroscopic analysis (IR, MS, 1H-NMR, 13C-NMR, HSQC, HMBC, COSY and NOESY or ROESY), with 8 sterols and one alkaloid. These compounds are cholesterol (1), 6α-hydroxy-cholest-4, 22-diene-3-one (2), ergosta-6α-hydroxy-4, 24 (28)-dien-3-one (3), 6α-hydroxystigmast-4-en-3-one (4), 2'-deoxyuridine (5), stigmast-4-en-6α-ol-3-one (6), 6α-hydroxystigmasta-4, 22-dien-3-one (7), ergosta-6a-hydroxy-4, 22-E-dien-3-one (8), p-hydroxybenzaldehyde (9). All of these compounds except 1, 5 and 9 were isolated from this sponge for the first time, but none of which are new.The marine sponge Plakortis simplex belongs to class Demospongiae, order Hamosclerophorida and family Plakinidae. From this sponge we isolated 14 and identified 7compounds including 6 sterols and only 1 terpene. These compounds are Plakorterpene A (10). 5α, 6α-epoxycholesta-7, 22-en-3β-ol (11), 5α, 6α-Epoxystigmasta-7, 22, 25 (27)-en-3β-ol (12), 5α, 6α-Epoxy-22-en-3β-ol (13), 5α, 6α-epoxyergosta-7-en-3β-ol (14), 5α, 6α-epoxystigmasta-7, 22-en-3β-ol (15), 5α, 6α-epoxystigmasta-7-en-3β-ol (16). All of these compounds were isolated from this specimen of sponge for the first time, and compound 10, 12 are new.This was the first systemic study on the bioactive constituents of marine sponge Haliclona oculata and Plakortis simplex in Xisha, China, which established a foundation for further development of these two marine organisms with abundant resources in China.