History of Cholesterol Autoxidation
Systematic study of the chemical oxidation begun by Mauthner by 1894  was closely followed by the first published accounts by Israel Lifschütz of encounters with cholesterol autoxidation products whose nature was unrecognized at the time [561,1473]. Experimental work on cholesterol autoxidation may be traced back to Lifschütz’ work of 1895 on wool fat in which the use of different color tests for cholesterol figured prominently [558–561,1473]. From that time the history of cholesterol autoxidation closely parallels the advances made in cholesterol chemistry and suggests that the early biochemistry of cholesterol derived directly from the early attempts to overcome some of the problems associated with cholesterol in which cholesterol autoxidation intruded. The history of study of cholesterol autoxidation may be conveniently divided into three separate phases: (i) an early phase dominated by the work of Lifschütz which included many random observations of oxidative transformations of cholesterol, made before the structure of cholesterol was known and ending with the assignment of the correct structure of cholesterol in 1932; (ii) an intermediate phase involving additional random observations, with isolation from tissues for the first time of identified cholesterol oxidation products, including the 3β,5α,6β-triol 13, the 7-ketone 16 and the epimeric 3β,7diols 14 and 15; and (iii) the most recent phase dating from about 1960 in which application of effective thin-layer chromatography procedures in systematic fashion led us to the present stage of our knowledge of cholesterol autoxidation as adumbrated in this monograph.