alkaloids 1

Definition: the term “alkaloid” (alkali-like) is commonly used to designate basic heterocyclic nitrogenous compounds of plant origin that are physiologically active.
True alkaloids (Typical) which are derived from amino acids and have nitrogen in a heterocyclic ring, like Atropine
Protoalkaloids which are derived from amino acids and do not have nitrogen in a heterocyclic ring like Ephedrine
Pseudo alkaloids which are not derived from amino acids but have nitrogen in a heterocyclic ring like Caffeine
Distribution and occurrence:
Rare in lower plants.
Dicots are more rich in alkaloids than Monocots.
Families rich in Alkaloids: Apocynaceae, Rubiaceae, Solanaceae and Papaveracea.
Families free from Alkaloids: Rosaceae, Labiatae
All Parts e.g. Datura.
Barks e.g. Cinchona
Seeds e.g. Nux vomica
Roots e.g. Aconite
Fruits e.g. Black pepper
Leaves e.g. Tobacco
Latex e.g. Opium
Free bases
Salts with Organic acids e.g. Oxalic, acetic acids
Salts with inorganic acids e.g. HCl, H2SO4.
Salts with special acids: e.g. Meconic acid in Opium Quinic acid in Cinchona
Glycosidal form e.g. Solanine in Solanum