Atividade antimicrobiana de fungos endofíticos isolados de Cochlospermum regium e caracterização de compostos utilizando redes moleculares

Abstract

Given the increasing demand for sustainable alternatives in the control of phytopathogens and resistant microorganisms, endophytic fungi have emerged as promising sources of bioactive compounds with agricultural and biotechnological potential. This dissertation aimed to evaluate endophytic fungi isolated from the plant Cochlospermum regium and their crude extracts for antimicrobial activity against the phytopathogen Sclerotinia sclerotiorum (white mold) and pathogenic bacteria, and cytotoxic activity as well as to characterize their chemical profiles through molecular networking. Isolates Cr-11 and Cr-12 showed significant mycelial inhibition rates of S. sclerotiorum, at 85.25% and 78.10%, respectively, demonstrating biocontrol potential. Chemical profiling, performed on the GNPS2 platform, led to the annotation of 51 compounds, 15 of which had suggested chemical structures, while the remainder were classified at levels 4 and 5, indicating a rich diversity of secondary metabolites. Cytotoxicity assays showed no toxic effects on human cell lines, supporting the safety of the evaluated microorganisms. On the other hand, the tested fractions, at concentrations of 20 mg/mL and 40 mg/mL, did not exhibit inhibitory effects against Stenotrophomonas maltophilia and Escherichia coli, highlighting the need for further studies to better understand the activity of these compounds against different microorganisms. Overall, the results suggest that endophytic fungi from C. regium are potential agents for agricultural disease management and promising candidates for future biotechnological applications.