Prospecção de compostos com potencial anticâncer obtidos de microrganismos associados à ascídia Euherdmania sp.

Abstract

Cancer is the second most prominent cause of death among the world, being characterized with cells presenting abnormal growth and the ability to invade tissues unlike the one of origin. Most of the chemotherapeutics drugs available in clinic are cytotoxic, with specificity and efficacy below the desirable parameters.The search for new chemotherapeutics of marine source is highly promising. A proof of that is most chemotherapeutics in commercial have a natural source, or are derived from natural products. Marine natural products (MNP) are interesting sources of molecules in pre-clinical phase or pharmaceuticals with high potency. Organic extracts of ascidian Euherdmania sp., as well as the bacteria associated to it, from the Ceará’s litoral show a diversity of biological activities, including cytotoxicity, therefore being an interesting source for the prospection of microorganisms that produce secondary metabolites with anticancer potential. The principal aim of this work was the prospection of compounds with anticancer potential from microorganisms associated to Euherdmania sp. The ascidian and its associated sediment, collected in Taíba - CE, were processed and had its microbiota cultivated in a medium containing a nutritive ascidian extract. From this procedure were obtained 10 isolated strains. These had their organic extracts tested against HCT 116 colorectal cancer cell lines in the Sulforhodamine B (SRB) assay, with 72 hours of incubation. Extracts presenting cytotoxicity above 75% were selected for the calculation of the medium inhibitory concentration IC50. The extracts considered cytotoxic were those of the following bacteria: BRA-612, BRA-613, BRA-616, BRA-624 and BRA-632. Results found indicate the presence of substances belonging to the prodiginine class in the strain BRA-612. Heptylprodigiosin was found in the extract, with and IC50 of 0,094 µM against HCT 116 cell lines and an IC50 0,195 µM against B16-F10 cell lines. The cytotoxicity of heptylprodigiosin was first announced in this work. The 16S rDNA sequencing allowed the identification of BRA-612 as a member of the Pseudovibrio sp. family, being refered to as Pseudovibrio sp. BRA-612. Therefore, heptylprodigiosin was obtained with a yield of 9% and novel anticancer activity in vitro, reinforcing the biotechnological potential of molecules derived from marine invertebrates.