Monoterpene indole alkaloids as leads for targeting multidrug resistant cancer cells from the African medicinal plant Tabernaemontana elegans

Multidrug resistance (MDR) is the main challenge in cancer treatment. Several mechanisms of MDR have been proposed, such as an increased drug efflux due to the overexpression of ABC drug transporter proteins, or a deregulation of apoptosis. Thus, the development of ABC-transporter modulators and the search for effective apoptosis inducers have been considered realistic strategies for overcoming MDR. Exploiting collateral sensitivity is also comprised among the most promising approaches to tackle MDR. Aiming at obtaining a library of monoterpene indole alkaloids for overcoming MDR, we have been carrying out the phytochemical study of the African medicinal plant Tabernaemontana elegans (Apocynaceae), by using both approaches isolation and molecular derivatization. The results, summarized in this review, showed that several indole alkaloids, of both natural origin or obtained by derivatization, are promising potential lead structures for reversing MDR.