It is shown that the demosponge Corallistes sp. (Tetractinomorpha, Lithistida, Corallistidae) collected in the Coral Sea, contains corallistin A (1), the second example, of a free porphyrin from a living organism. The compound proved to be active against the Kb cell line. In contrast with the geoporphyrins which do not bear any O-atom corallistin A (1) carries two carboxylic groups.

SMIB 1, SMIB 2, SMIB 3, SMIB 4

Reported here are the novel free porphyrins corallistin B, C, D, and E, isolated as methyl esters 2a, 3a, da, and 5a, respectively, from the sponge Corallistes sp. (Lithistida) collected at the basis of the south New Caledonian coral reef. A protocol is also established for formylation of their Ni" complexes, which show a different reactivity pattern toward DMF/POCI, from metal complexes of deuteroporphyrins. Together with corallistin A, previously isolated as the methyl ester la, and the known deuteroporphyrin IX (isolated as 6a) also present in the sponge, the new corallistins, which may be thought to derive from protoporphyrin viu heme, account for an amazing 60% of the EtOH extract from the sponge.

SMIB 1, SMIB 2, SMIB 3, SMIB 4, SMIB 5, SMIB 6

Agelastatin A, isolated from the axinellid sponge Agelas dendromorpha of the Coral Sea, is a new-skeleton alkaloid with, unusually for the oroidin family to which it belongs, marked cytotoxicity toward tumour cells in culture.

SMIB 4, SMIB 5

Le benthos profond récolté tout d'abord lors des campagnes océanographiques MUSORSTOM IV (1) et CHALCAL (2), puis lors des campagnes de récoltes SMlB (1986, 1987, 1989) s'est avéré être extrèmement riche en invertébrés divers dont beaucoup sont nouveaux. L'abondance et l'originalité de cette faune nous a conduit à étudier une cinquantaine d'organismes recoltés entre 200 et 700m: éponges (40), échinodermes (1 O), alcyonaires (2), madréporaires (1).

CHALCAL 1, MUSORSTOM 4

The lithistid sponge Corallistes undulatus, which inhabits the base (- 510 m) of the New Caledonian coral reef, is shown here to contain the pteridines 1-methylpteridine-2,4- dione, already known from another Corallistes, and the new(1'R,2'S)-6-(1',2'-dihydroxypropyl)- 1-methylpteridine-2,4-dione together with the steroids 3ß-hydroxy-24- methylenecholest-5-en-7-one, 7-ALPHA-hydroxysitosterol,7ß -hydroxysitosterol, and 3ß-hydroxystigmast-5-en-7-one, typical of higher terrestrial plants, and the indole derivatives methyl(2E)-3-(indol-3-yl)-2-propenoate, methyl(2E)-3-(6-bromoindol-3-yl)- 2-propenoate, and serotonin. The presence of the same compounds in taxonomically, phyletically, and ecologically unrelated organisms is viewed here as resulting from evolutionary convergence toward adaptive products.

SMIB 4, SMIB 5