Six new compounds, talamitones A and B (1 and 2), demethyltalamitone B (3), talamiisocoumaringlycosides A and B (4 and 5), and talaminaphtholglycoside (6), together with six known compounds (7-12), were isolated from the marine-derived fungus Talaromyces minnesotensis BTBU20220184. The new structures were characterized by using HRESIMS and NMR. This is the first report of isocoumaringlycoside derivatives from a fungus of the Talaromyces genus. Compounds 5, 6, and 9 showed synergistic antibacterial activity against Staphylococcus aureus.

Fungal colorants are gradually entering the global color market, given their advantages of being less harmful to human health, as well as having greater stability and biotechnological potential, compared to other natural sources. The present work concerns the isolation and identification of an endophytic filamentous fungus, together with the chemical characterization and assessment of the fluorescence, toxicity, stability, and application potential of its synthesized red colorant. The endophytic fungus was isolated from Hymenaea courbaril, a tree from the Brazilian savannah, and was identified as Talaromyces minnesotensis by phenotypic and genotypic characterization. Submerged cultivation of the fungus resulted in the production of approximately 12 AU500 of a red biocolorant which according to LC-DAD-MS analysis is characterized by being a complex mixture of molecules of the azaphilone class. Regarding cytotoxicity assays, activity against human hepatoblastoma (HepG2) cells was only observed at concentrations above 5.0 g L-1, while antimicrobial effects against pathogenic bacteria and yeast occurred at concentrations above 50.0 g L-1. The biocolorant showed high stability at neutral pH values and low temperatures (10 to 20 °C) and high half-life values (t1/2), which indicates potential versatility for application in different matrices, as observed in tests using detergent, gelatin, enamel, paint, and fabrics. The results demonstrated that the biocolorant synthesized by Talaromyces minnesotensis has potential for future biotechnological applications. KEY POINTS: • An endophytic fungus, which was isolated and identified, synthesize a red colorant. • The colorant showed fluorescence property, low toxicity, and application potential. • The red biocolorant was highly stable at pH 8.0 and temperatures below 20°C.