Substances found commonly in various plants. They are natural nitrogenous organic bases and combine with acids to form crystalline salts. Among alkaloids, morphine was discovered in 1805, strychnine in 1818, quinine and caﬀeine in 1820, nicotine in 1829, and atropine in 1833. Only a few alkaloids occur in the animal kingdom, the outstanding example being ADRENALINE, which is formed in the medulla of the suprarenal, or adrenal, gland. Alkaloids are often used for medicinal purposes. The name of an alkaloid ends in ‘ine’ (in Latin, ‘ina’).
Neutral principals are crystalline substances with actions similar to those of alkaloids but having a neutral reaction. The name of a neutral principal ends in ‘in’, e.g. digitalin, aloin.
The following are the more important alkaloids, with their source plants:
Aconite, from Monkshood.
Atropine, from Belladonna (juice of Deadly
Cocaine, from Coca leaves.
Hyoscine, from Henbane.
Morphine, Codeine, from Opium (juice of
Poppy). Thebaine, Nicotine, from Tobacco. Physostigmine, from Calabar beans. Pilocarpine, from Jaborandi leaves. Quinidine, from Cinchona or Peruvian bark. Strychnine, from Nux Vomica seeds.