PREUPLOTIN, A PUTATIVE BIOGENETIC PRECURSOR OF THE EUPLOTINS, BIOACTIVE SESQUITERPENOIDS OF THE MARINE CILIATED PROTIST EUPLOTES-CRASSUS

Strains of the marine ciliated protist Euplotes crassus typically contain preuplotin {(all-E)-2-[6-acetoxy-4-(acetoxymethylene)hex-5-enylidene]-6-methylhept-5-enal} 4. This represents the C-12 deprenyl analogue of udoteal, the feeding-deterrent of tropical seaweeds of the genus Udotea. Euplotes crassus typically contains also the O-cyclized form euplotin C 3 which may bethought to descend biogenetically from preuplotin together with euplotins A and B previously isolated from highly-productive strains of this ciliate as likely adjuvant factors of its adaptive radiation.