A NEW NORCEMBRANOID DIMER FROM THE RED-SEA SOFT CORAL SINULARIA-GARDINERI

A study of Sinularia gardineri (Pratt) (Alcyoniidae), collected in the Red Sea, revealed a new heptacyclic norcembranoid dimer singardin (1) . The structure of singardin was deduced by spectroscopic analysis. A known sesquiterpene, guaianediol (2), and the known cembranolides (1R, 5S,8R, l-8-methyl-3,6-dioxo-5,8-epoxycyclotetradec-12-ene 10,12-carbol actone (5-epi-sinuleptolide) and sinuleptolide were also isolated. Com pounds 1 and 2 show cytotoxicity to murine leukemia (P-388), human lun g carcinoma (A-549), human colon carcinoma (HT-29), and human melanoma cells (MEL-28).