alkaloids

Alkaloids
Definition: the term “alkaloid” (alkali-like) is commonly used to designate basic heterocyclic nitrogenous compounds of plant origin that are physiologically active.
Classification: ? True (Typical) alkaloids that are derived from amino acids and have nitrogen in a heterocyclic ring. e.g Atropine ? Protoalkaloids that are derived from amino acids and do not have nitrogen in a heterocyclic ring. e.g Ephedrine ? Pseudo alkaloids that are not derived from amino acids but have nitrogen in a heterocyclic ring. e.g 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
Distribution in Plant:
? 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 .