STEROIDS

1. They are a group of tetracyclic lipid derivatives which have a nucleus of cyclopentano-perhydrophenanthrene with phenanthrene part made of 3 hexane rings while the fourth ring is a pentane.
2. The most common sterol is cholesterol.
3. Ergasterol occurs in cell membranes of ergot fungi, yeast.
4. Coprosterol is found in stool. It is formed by bacterial reduction of cholesterol.
5. Sitosterol present in wheat germ oil.
6. Steroids are of two types -

(i) Alcoholic steroids (Sterol) - Cholesterol, Coprosterol, 7-dehydroxycholesterol, Bile salts

(ii) Ketonic steroids (Sterone) - Ecdyson, Diosgenin, Adrenocorticoids, Sex hormone