PTERIDINES, STEROLS, AND INDOLE-DERIVATIVES FROM THE LITHISTID SPONGE CORALLISTES-UNDULATUS OF THE CORAL SEA

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[2], already known from another Corallistes, and the new (1'R,2'S)-6-(1',2'-dihydfoxypropyl)-1-methylpteridine-2,4-dione [(-)-8], together with the steroids 3beta-hydroxy-24-methylenecholest-5-en-7-one [15], 7alpha-hydroxysitosterol [16],7beta-hydroxysitosterol [17], and 3beta-hydroxystigmast-5-en-7-one [18], typical of higher terrestrial plants, and the indole derivatives methyl(2E)-3-(indol-3-yl)-2-propenoate [19], methyl(2E)-3-(6-bromoindol-3-yl)-2-propenoate [20], and serotonin [21]. The presence of the same compounds in taxonomically, phyletically, and ecologically unrelated organisms is viewed here as resulting from evolutionary convergence toward adaptive products.