Epistane is a general term for a large class of cyclopental fused hydrogenated phenanthrene derivatives widely distributed in the biological world. Also known as steroids, steroids. 

Steroid compounds are free of bound fatty acids and are non-saponifying lipids; such compounds are classified as isoprenoids and are formed by tricyclic cyclization followed by intramolecular recombination and chemical modification.


Epistane include sterols (such as cholesterol, lanosterol, sitosterol, sterol, ergosterol), bile acids and bile alcohols, steroid hormones (such as adrenocortical hormones, androgens, estrogens), insect ecdysone, Cardiac glycosides and saponins, as well as scorpion venom and the like.
In addition, there are synthetic steroid drugs such as anti-inflammatory agents (prednisolone, dexamethasone), steroid drugs that promote protein synthesis, and oral contraceptives.