Discovery of cytotoxic natural products from South African marine sponges

Abstract

Cancer is a major health problem worldwide and killing millions of people each year. The use of natural products as chemotherapeutic agents is well established, however, many of the currently available drugs are associated with undesirable side effects and high toxicity. Furthermore, the development of drug resistant cancers makes the search for anticancer lead compounds a priority. In this study a library of prefractionated marine sponge extracts was established and used to prioritise samples for isolation of bioactive metabolites. From the generated library, two of the sponges of genera Ircinia sp. and Latrunculid sp. resulted in isolation of furanosesterterpenes (7E,12Z,20Z,18S-variabilin) and pyrroloiminoquinone (tsitsikammamine A and tsitsikammamine N-18 oxime) alkaloids respectively. The structures of these compounds were elucidated by analysis of 1D and 2D NMR data. These compounds displayed moderate to potent cytotoxicity against MCF-7, PC-3, U-87 and HEK-293 cells lines through apoptosis, with lack of selectivity for cancer cell lines.