Minor and trace sterols in marine invertebrates: VI. Occurrence and possible origins of sterols possessing unusually short hydrocarbon side chains

摘要: Abstract Sterols with biosynthetically unusually short side chains (fewer than eight carbon atoms expected for primary squalene cyclization products) have been identified in the extracts of numerous marine invertebrates. The structures chain and conventional sterols determined various species Porifera Coelenterata. Sterol were by comparison their mass spectra gas chromatographic retention times those authentic or synthetic samples. Evidence is presented supporting natural occurrence these compounds tissues invertebrates as opposed to formation degradative processes during sample handling laboratory work-up. found possess predominantly androst-5-en-3β-ol nucleus C-17 alkyl ranging from zero six atoms. Concentrations range trace levels over 5% sterol mixture species. possible origins are evaluated light current knowledge function, biosynthesis, dealkylation, microbial degradation, autoxidation. Known autoxidations reviewed, singlet oxygen free radical mechanisms autoxidation (at physiological temperatures) which may lead shortened hydrocarbon suggested. autoxidative generation known suggested through application REACT computer program. Predicted tabulated each parent then compared compositions actual examined. environmental vivo supported evaluations.