Analysis of secondary metabolites with antibacterial activity from Aspergillus and Penicillium strains endemic to Bénin

Food intended for consumption can be contaminated with pathogens, such as the bacteria responsible for gastroenteritis, through either accidental exposure or the use of unhygienic practices. This creates a vicious circle of food-borne illnesses that are difficult to treat, particularly in light of antibiotic resistance. In light of this situation, the search for new bioactive molecules is becoming crucial. Fungi, with well-developed secondary metabolism, are a significant source of bioactive compounds. The dual objective of this study was to identify and evaluate the antibacterial activity of families of fungal secondary metabolites on the bacteria responsible for gastroenteritis. To carry out this study, the aforementioned fungal strains were tested against the bacterial strains Staphylococcus aureus ATCC 25923, Salmonella sp., Shigella sp., Vibrio cholerae and Escherichia coli. The fungal metabolites were harvested after an incubation period of 21 d in PDB broth. Thin layer chromatography and bioautography of the different extracts were conducted to evaluate the activity of the various compounds against the bacterial strains. The results of chromatographic analysis indicated that the secondary metabolite families responsible for the observed activity were primarily coumarins and flavonoids. All fungal strains belonging to the genera Aspergillus and Penicillium exhibited notable antibacterial activity, as indicated by the presence of zones on the plate. This observation suggests that the observed activity may be linked to specific families of secondary metabolites produced by these fungi.