Atividade biológica e investigação de compostos obtidos de Streptomyces sp. isolado de sedimentos do Lago Verde em Alter do Chão

Abstract

One of the major challenges in public health is the resistance of pathogens to various drugs, leading to intense searches for new antimicrobial agents from natural sources, through the exploration of new niches. The objective of this research was to investigate actinobacteria from sediments of Lago Verde in Alter do Chão, Pará, Brazil, evaluating their antibacterial, cytotoxic and antioxidant activity, as well as investigating the chemical profile of the volatile compounds present in the crude extract. Identification occurred through morphological and biochemical evaluation. Their antibacterial activity was investigated by the agar disk method (6 mm), against 17 pathogens of clinical interest. Cytotoxic activity was determined by the percentage inhibition of cell growth in samples of the human colorectal carcinoma cell line HCT116, using a concentration of 10 μg/mL, with the results expressed as mean ± SEM (n = 2). Antioxidant activity was determined by the DPPH radical neutralization assay. The chemical profile of the volatile compounds in the crude extract was established by gas chromatography-mass spectrometry (GC-MS) analysis. The identification of the isolate LV20 presents characteristics of the phylum Actinobacteria, compatible with the genus Streptomyces; its antibacterial activity demonstrated action against Staphylococcus epidermidis (17.75 ± 1.25) and Enterococcus faecalis (17.5 ± 0.5), in addition to reducing the HCT116 tumor cell line, with 95.55% inhibition. The crude extract of LV20 showed significant antioxidant activity by the DPPH method, evidenced by a 50% Effective Concentration (EC) of 890.29 μg/mL. The chromatographic analysis identified bioactive volatile compounds, with emphasis on glycerol (28%), tris(2,4-di-tert-butylphenyl)phosphate (22.12) and benzenepropanoic acid, 3,5-bis(1,1- dimethylethyl)-4-hydroxyoctadecyl (14.67%), which present pharmacological potential. The unprecedented results demonstrate the biological variability of Streptomyces sp. LV20 as a promising source of bioactive molecules with therapeutic applications, highlighting the importance of Amazonian biodiversity for the bioprospecting of new drugs as an alternative in the face of microbial resistance.