Caracterização química e atividade biológica de compostos obtidos de Streptomyces sp isolado de solo de várzea na Amazônia

Abstract

The extensive use of antibiotics in the therapy of infectious diseases has contributed to the emergence of resistant bacterial strains, representing a significant challenge to public health. Treatment resistance is not limited to just antibiotic therapy; cancer treatment presents similar challenges. In this context, the search for new antimicrobial and anticancer agents from natural sources can be an important strategy in the discovery of new bioactives. In this study, native actinobacteria were isolated from floodplain soil collected in the Saracura community, on the banks of the Amazon River, and a chemical study was carried out using the crude extract through analysis by Gas Chromatography coupled to Mass Spectrometry (CG-MS) and High-Performance Liquid Chromatography (HPLC) in reversed phase. The identification of the isolates was carried out through morphological, biochemical and molecular characterization through sequencing of the 16S rRNA gene. Antimicrobial activity studies were carried out using agar block testing against 15 pathogens of clinical interest to select the promising isolate and obtain the crude extract using the solvent ethyl acetate. The crude extract obtained was used to study antioxidant and antitumor activity and to a chemical investigation. 4 isolates of actinobacteria were obtained, identified as Streptomyces sp., renamed as VAR1, VAR2, VAR4 and VAR5. PKS and NRPS biosynthetic genes were amplified in all isolates. In the antagonism assessment, it was verified that all isolates were active against at least 1 pathogen of clinical interest, with emphasis on Streptomyces sp. VAR2 which produced a growth inhibition halo of 18mm against Aeromonas hydrophyla, and 16mm for Proteus vulgaris. The crude extract of the isolated Streptomyces sp. VAR2 promoted cell growth inhibition of human colorectal carcinoma lineage by 95.87% at a concentration of 10 μg/ml. Furthermore, a free radical scavenging activity of DPPH of 7.90% and ABTS of 20.75% was verified. The GC-MS analysis of the crude extract of the isolated Streptomyces sp. VAR2 revealed the majority presence of the compound 2-Decanol, methyl ether, not yet reported in the literature as bioactive, followed by l-(+)-Ascorbic acid 2,6-dihexadecanoate, a compound already described in the literature with antioxidant activity. The results of this research indicate the ability of these bacteria to produce compounds with varied biological activity, which may indicate, in the future, new therapeutic options for emerging global health problems such as microbial resistance and cancer treatment.