Caracterização química e atividade biológica de compostos obtidos de actinobacté - rias isoladas de rochas carbonáticas na Amazônia

Abstract

The carbonate rocks of the Itaituba Formation date back approximately 300 million years, preserving geological events and biogeochemical processes of degradation of organic matter, suggestive of the presence of actinobacteria with properties not yet documented. Therefore, the present study proposes to perform the bioprospecting of actinobacteria isolated from carbonate rocks in the Amazon. A total of 21 isolates, PML1 to PML21, were evaluated in the production of antimicrobial substances by agar diffusion against pathogens to identify promising isolates. Morphological and biochemical characterization took place following the International Streptomyces Project. From obtaining the extracts through the solvent ethyl acetate, the cytotoxic action of the human colorectal cancer cell line (HCT-116) and antioxidant activity of the most promising isolates was evaluated.dant substances of interest to the biotechnology industry.Next, the HPLC-DAD and CG-MS tests were performed. Morphologically, most isolates had white airy mycelium and yellow vegetative mycelium. Of the 21 actinobacteria isolated, 13 were active against at least one of the 11 pathogens tested, with a spectrum of action ranging from Gram-positive to Gram-negative bacteria. PML5 with a halo of 16 mm + 0.00 against Salmonella enteridis INCQS00268, PML11 with a halo of 27 mm + 0.00 against Micrococcus lutteus ATCC7468 and PML15 with a halo of 17 mm + 1.0 against Proteus vulgaris ATCC13315 and 17 mm + 0.00 against Aeromonas hydrophyla INQS00318. Regarding enzyme production, the promising isolates showed enzyme index for Lipase, Esterase, Caseinase and positivity for Catalase. The cytotoxic test showed the cytotoxic activity of PML5 with an inhibition of 96.5% of the cell growth of the human colorectal cancer cell line (HCT-116), being, therefore, the most promising isolate. The antioxidant action of PML5 was also verified by the capture of the free radical ABTS with an inhibition of 35.60%, and by the capture of the free radical DPPH with an action of 10.65%, at the tested concentration. The extract of the PML5 strain was analyzed by HPLC and showed the presence of four peaks, where there were similar absorbance patterns, indicating the possibility of the extract having metabolic pathways that synthesize substances of the same class. The CG-EM of the extract showed the presence of 10 volatile compounds. The main compound was Cyclododecane compared to other bioactive compounds. These results demonstrate the potential of Amazonian biodiversity, revealing the carbonate rock isolate PML5 as a producer of antimicrobial, cytotoxic and antioxidant substances of interest to the biotechnology industry.