Coprosterol is present in faeces. It is the reduced form of cholesterol, formed as a result of reduction by intestinal bacteria. It does not have the double bond between C5 and C6.
Calciferol is an activated ergosterol.
Ergot is present in ergot and yeast. It’s an important compound because it’s a precursor of vitamin D, which is converted by irradiation with UV. It has double bond in the side chain. It has an additional CH3 group in the side chain. Its structure is as follows:
This is an important sterol present in the skin. It has one more double bond at C7 – C8. It has only one H atom at C7 – C6 and none at C8. It is converted to vitamin D when irradiated with UV. Its structure is as follows:
Cholesterol is the precursor of various physiologically important compounds like bile acids, female sex hormones, and steroid hormones of adrenal cortex.
Liebermann–Burchard reaction The intensity of colour is proportional to the concentration of cholesterol. This reaction is used for the quantitative determination of cholesterol in blood.
The chemical properties are related to the secondary hydroxyl group and the double bond at C5 – C6. Cholesterol, when oxidised in suitable conditions, undergoes rapid oxidation to corresponding ketone and cholestenone. The hydroxyl group readily forms esters with acids. The fatty acid esters, namely cholesterol acetate palmitate and propionate, are found in blood and tissues.…
Physical properties They are white shining rhombic plate like crystals. They are tasteless and odourless. Cholesterol has a high melting point of 150°C. Cholesterol is insoluble in water and soluble in fat solvents (chloroform, acetone, and benzene). It is soluble in soap solution and bile salt solution. When mixed with fat or oil, cholesterol has…