Potencial antitumoral de extratos e de frações obtidos de microrganismos associados aos zoantídeos Palythoa caribaeorum e Palythoa variablilis da costa cearense e do arquipélago Fernando de Noronha

Abstract

The world has effortlessly sought ways to prevent, treat and cure people with cancer for a long time. Despite many research efforts, this disease is still one of the biggests health-issues, which encourages one to look for new sources with anticancer properties. Marine invertebrates are very promising as a source of potential antitumoral compounds. Considering that there are many evidences suggesting that microorganisms associated with these animals play a fundamental role in the production of these compounds, this study aimed to evaluate the antitumoral potential of actinomycetes, associated with Palythoa caribaeorum and Palythoa variablilis of Fernando de Noronha archipelago and Ceará coast. The antiproliferative activity of the actinomycetes named as BRA – 350 e 351 was evaluated using the MTT assay, after the isolation and extraction of those cultures. The extraction, fractionation and antiproliferative activity was also evaluated for the strain BRA – 036, which was isolated previously from Palythoa variablilis. The fractions were also analyzed with thin layer chromatography (TLC). Aditionally, the optimum time to obtain the most active extract in a 10-days cultures of BRA – 036. The inhibition percentage of 5 μg/mL of BRA – 036- derived extract in HCT – 116 cells was 87.43 %. On the other hand, P. caribaeorumassociated actinomycetes did not significantly inhibit HCT – 116 growth. The analysis using TLC evidenced the presence of indolic compound, potentially diketopiperazines, which can be empowered of multiple biological activities. The fraction of BRA – 036 with the highest activiy was the one obtained with AcOEt/MeOH (2:1). The half maximum inhibitory concentration (IC50) calculated for BRA – 036 was 4,28 ng/mL, which demonstrated the extract’s potency. As the optimum time to obtain the most potent extract was 2 days, this result contributes for timing-optimization of bioprospecting of compounds with anti-tumoral activities produced by this actinomycete. The findings presented in this study highlight the antit-tumoral potential of microbes associated with the zoantids P. caribaeorum e P. variablilis and inspire the scientific community to isolate and identify the molecules presented in its extracts.