ABSTRACT
Alkaloids have been known to man for several centuries and are used for human welfare. Among various groups of secondary metabolites, alkaloids are the most extensively investigated compounds. Of all known natural products, about 20% (i.e., about 16,000) are classified as alkaloids. The biological activity of several of these has been investigated but only 30 alkaloids are produced at the commercial level. Most are medicines but some are used as flavouring, poison, and model compounds for pharmacological activity. These alkaloids can be classified as novel chemicals, as their world production is limited, e.g., quinine and quinidine have a yearly production of 300-500 kg, while compounds such as vincristine and vinblastine are produced in a few kilogram range. If we compare this system to cane sugar production from sugar-cane (plant-based primary product), biomass utilization for extraction of alkaloids is very small. For the aforesaid quantities of alkaloids, 5000-10,000 tons of Cinchona bark, 200-300 tons of Catharanthus roseus roots are required for quinine and vincristine respectively. The price of these compounds is exorbitant, which is why secondary metabolites are termed low-volume, high-value products.
