BIOPROSPECÇÃO DE METABÓLITOS SECUNDÁRIOS PRODUZIDOS POR MICRORGANISMOS ENDOFÍTICOS DE PLANTAS MEDICINAIS DA REGIÃO DA AMAZÔNIA LEGAL

Abstract

The dangers of a post-antimicrobial era have led policymakers to recognize its threat to human health, requiring urgent action to develop new antimicrobial therapies and, most importantly, to reduce human contribution to the increase in resistance. The objective of this research was to evaluate the antimicrobial action of secondary metabolites produced by an endophytic microorganism against clinical isolates of interest. For the definition of the botanical material to be analyzed, a bibliographic survey of medicinal plants consumed in Maranhão was carried out, and samples were collected from a residence; leaves were chosen as the plant part for the isolation of endophytes. The induction of metabolite production was performed using the Submerged Fermentation technique, followed by extraction with ethyl acetate. The evaluation of the antibacterial activity of the secondary metabolites was conducted through agar diffusion assays, microdilution, and antibiofilm analysis. The endophytic microorganism was isolated from the leaf of Aloe vera; the macro- and microscopic identification of this microorganism identified it as a bacterium belonging to the genus Streptomyces. After obtaining the metabolites, the test results demonstrated that they were capable of inhibiting the growth of Corynebacterium propinquum strains, with the formation of halos up to 27±0 mm and a minimum inhibitory concentration (MIC) of 32.1 µg/mL. The biofilm interference test showed that the extract reduced biofilm formation in C. propinquum, Candida parapsilosis, and C. albicans strains. The toxicity assay revealed that the concentration of 31.2 µg/mL of the extract is safe for the larvae of Tenebrio molitor. The evaluation of larval survival after infection with C. propinquum demonstrated that the group treated with the metabolites had a higher survival rate than the untreated group. Thus, it is concluded that the extract produced by the actinobacterium exhibited antibiotic potential against clinical strains of C. propinquum, a rare pathogen described as causing infections in patients with pulmonary involvement, pleural effusion, bacteremia, and endocarditis, which exhibits emerging antibiotic resistance.