Zyzzyanones B-D, dipyrroloquinones from the marine sponge Zyzzya fuliginosa.

Zyzzyanones B, C, and D (2-4), three new dipyrroloquinones with a pyrrolo[3,2-f]indole-4,8(1H,7H)-dione skeleton, have been isolated from the Australian marine sponge Zyzzya fuliginosa. The known zyzzyanone A, makaluvamines C, E, G, H, and L, damirones A and B, 3,7-dimethylguanine, and 4-hydroxybenzoic acid were also isolated. The structures of the new compounds 2-4 were established by extensive NMR spectroscopic data.

Biological activities of marine sesquiterpenoid quinones: structure-activity relationships in cytotoxic and hemolytic assays.

Sesquiterpenoid quinones from marine sponges and their semisynthetic derivatives were compared for cytotoxicity on developing eggs of sea urchin Strongylocentrotus nudus and Ehrlich carcinoma cells, and for hemolytic activities on mice red blood cells. Structure-activity studies showed that activities of these compounds with a hydroxyl group at C-20 ((2), (7)) were higher than their methoxyl ((1), (8)) and amino ((4), (5)) derivatives at this position. Sesquiterpenoid quinones containing a dihydropyran ring ((10)-(12)) had lower activity than noncyclic compounds.

Determination of the absolute stereochemistry of cyclosmenospongine.

The absolute stereochemistry of the sponge metabolite cyclosmenospongine (1) was determined as 5R, 8S, 9R, 10S by chemical correlation. Substitution of the methoxyl group by an amino group in the cyclic product 3 of acid-catalyzed rearrangement of ilimaquinone (5) afforded cyclosmenospongine 1. Cyclosmenospongine was also obtained by acid-catalyzed cyclization of smenospongine (6).