Steroids are organic compounds made up of 17 carbon atoms consisting of fused rings, out of which three are six members, and one is five-membered rings. This can be obtained from plants as well as animals.

The word steroid came from sterols. Adrenal hormones, bile acid, and cortical hormones are some examples of Steroids. 1,2-cyclopentanophenanthrene is the basic structure that is present in steroids. If the substituent present in one steroidal compound changes, then a new molecule is produced that can vary in its therapeutic action.


  1. In a steroidal compound, six chiral carbons are present, so 64 optical isomers are possible. 5, 8, 9, 10, 13, and 14 are asymmetric carbons.
  2. All the cyclohexane can exist in two conformational forms: chair and boat. Chair conformation is more stable than the boat due to less angle strain.
  3. The stereoisomer exist based upon the ring A and ring B fused. The fusion of rings a and the can be cis or trans; therefore, two isomeric forms can be produced.
  4. The fusion of rings B/C and C/D are trans. It is due to the configuration of 8-beta and 9-Alpha hydrogen, 14-Alpha hydrogen, and carbon 18 methyl.
  5. 5 Alpha cholestane contains trans, anti-trans, and anti-trans fusion of rings.
  6. 5-beta cholestane contains A/B rings with cis fused and cis-syn-trans and antitrans backbone. A student needs to learn about the configuration of steroids as these are fundamental units. If they find difficulty knowing it, they can go through steroid homework help.

Types of sterols:

  • Zoo sterol: it is mainly present in animals. Example: cholesterol. It can be found in free form or Ester form. The molecular formula of cholesterol is C27H25 It contains a hydroxyl group, a hydrocarbon tail, and four fused rings. The hydroxyl group is polar; hence it can easily solubilize in water.

The fused ring system and hydrocarbon tail are hydrophobic. Therefore, cholesterol is regarded as amphipathic because it contains both hydrophobic and hydrophilic parts in the structure. Cholesterol can be converted into cholestanol using hydrogen and Platinum as a catalyst.

  • Sapogenin: they contain steroids and triterpenes, which is why they are called tetracyclic triterpenoids. These are the aglycone parts obtained from saponins by enzymatic or acid hydrolysis. They can be identified based on the spiroketal chain present in the structure.

They are the derivatives of C-27 cholestane. A spiro compound comprises two cyclic rings that join through a single atom, and that atom is called a quaternary atom or spiro atom. Diosgenin, strophanthus, and digitally belong to this category.

  • Cardiac glycoside is a bitter, water-soluble component but insoluble in organic solvents. They are very toxic and odorless amorphous powder. They help increase the rhythm, excitability, and contractability of muscles present in the heart.

On enzymatic hydrolysis produces glycone and aglycone moieties that are cardenolides and bufadienolides. Cardenolides have one double bond in the lactone ring, with five members attached to the steroidal nucleus at 17 positions. Bufedienolides contain a 6-membered lactone ring with two double bonds attached to the steroidal nucleus at carbon number 17 alpha position.

  • Sex steroids: includes estrogen, androgen, and estrogens. It is also called gonadocorticoids/ gonadal steroids. It is hydrophobic and binds to the hormone receptor present in the cytoplasm. Androgen is formed from cholesterol produced in the testes and the adrenal cortex. Testosterone aldosterone is a naturally stimulating hormone in man. A detailed explanation is given at steroid assignment help by the experts of this stream.