Molecular Network of Monoterpene Indole Alkaloids (MIAs) Signaling in Plants with Reference to Catharanthus roseus (L.) G. Don

Terpenoids are the most functionally and structurally varied group of plant metabolites. These are synthesized in all organisms but are especially abundant and diverse in plants. Despite their diversity of functions and structures, all terpenoids are derived from the common five-carbon (C5) building unit, isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) through MEP pathway in all living organisms. The MEP pathway synthesizes IPP and DMAPP in plastids in plants and more complex terpenoids are usually formed by “head-to-tail” or “head-to-head” addition of isoprene units. Monoterpene indole alkaloids (MIAs) are one of important class of terpenoids which are C10 terpenoids, consisting of two isoprene units and are the components of more than 2000 defined compounds. These are a large group of plant-derived natural products with a range of pharmacological properties. These MIAs are potent drugs, such as anticancer, antimalarial, and antiarrhythmic agents. These MIAs have been found in eight different plant families, being most common in Apocynaceae, Rubiaceae, and Loganiaceae. Madagascar periwinkle, Catharanthus roseus, the best-characterized MIA-producing plant species, is the source of the valuable MIAs. It has approximately 130 alkaloids of indole group, out of which 25 are dimeric in nature. Some of these compounds have important medicinal properties such as anticancerous property (vincristine and vinblastine) and antiarrhythmic property (ajmalicine and serpentine). In the present chapter, molecular network of monoterpene indole alkaloids (MIAs) signaling in plants with reference to Catharanthus roseus (L.) G. Don has been reviewed.