Drugs Containing Alkaloids

Drugs Containing Alkaloids

INTRODUCTION

One of the largest groups of chemicals produced by plants is the alkaloids. Many of these metabolic by-products are derived from amino acids and include an enormous number of bitter, nitrogenous compounds. More than 10,000 different alkaloids have been discovered in species from over 300 plant families. Alkaloids often contain one or more rings of carbon atoms, usually with a nitrogen atom in the ring. The position of the nitrogen atom in the carbon ring varies with different alkaloids and with different plant families. In some alkaloids, such as mescaline, the nitrogen atom is not within a carbon ring. In fact, it is the precise position of the nitrogen atom that affects the properties of these alkaloids. These compounds are renowned for their potent pharmacological activities. Whilst tiny amounts of some can immobilize an elephant or a rhinoceros, others have important clinical use, such as analgesics, antimalarial, antispasmodics, for pupil dilation, treatment of hyperten-sion, mental disorders and tumours.

They are all nitrogen heterocycles which occur mainly in plants as their salts of common carboxylic acids, such as citric, lactic, oxalic, acetic, maleic and tartaric acids as well as fumaric, benzoic, aconitic and veratric acids. Their amine character produce an alkaline solution in water and hence the origin of their name—alkaloids.

Although they undoubtedly existed long before humans, some alkaloids have remarkable structural similarities with neurotransmitters in the central nervous system (CNS) of humans, including dopamine, serotonin and acetylcholine. The amazing effect of these alkaloids on humans has led to the development of powerful painkiller medications, spiritual drugs, and serious addictions by people who are ignorant of the properties of these powerful chemicals.