Bile, acid shark

Based on his examination of the bile salts of various species, Haslewood (1959) had concluded that an evolutionary pattern exists which is reflected in the pathway by which the cholesterol side chain is cleaved to yield the flve carbon acidic side chain of the bile acids. Thus, the older animals (shark) possess a side chain that has a 27 hydroxyl group, the reptiles mainly synthesize a 27 carboxylic acid and mammals a 25 carboxylic acid. Haslewood suggested that 3a, 7a, 12a-tri-hydroxycoprostanic acid might be an intermediate in cholic acid formation in 1952. 

Scymnol, C27H4JOJ, occurs as a sulphuric ester in shark bile, and is of interest in that it represents a compound intermediate in type between cholesterol and cholic acid, and may indicate their biochemical relationship. Scymnol has the same nucleus as cholic acid, but carries a different side-chain,... 

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