THE ISOLATION OF ISOAGATHENEDIOL - A NEW TRICYCLIC DITERPENE FROM THELIPIDS OF RHODOSPIRILLUM-RUBRUM

A tricyclic diterpene, isoagathenediol, has been isolated from the lip id fraction of the photosynthetic non-sulphur bacterium Rhodospirillum rubrum. The compound was present in trace amounts and its structure w as determined by NMR spectroscopy and mass spectrometry. Isoagathenedi ol is a new natural product and may function as a membrane fluidity mo dulator. Five other bacterial species have also been screened for the presence of this compound, but the diterpene was detected only in extr acts derived from R. rubrum. As tricyclic diterpene fossils are readil y detected in oil and shale samples, the isolation of isoagathenediol has indicated the biological origin of these fossils.