Biosynthesis and chemical characterization of an intracellular red pigment of Talaromyces islandicus T101

The interest in red colorants by the food industry has been increasing recently due to its wide application in many foods and beverages, and also to the carcinogenic and teratogenic effects of some synthetic dyes. Many ascomycetous fungi are able to synthesize and produce pigments, rendering them as alternative sources of natural dyes that are independent of environmental conditions. Talaromyces islandicus TI01 was isolated from a marine-influenced environment that has been suffering for decades from anthropogenic actions in its body of water. Broth microdilution technique was performed to analyze the antimicrobial activity. For analysis of the cytotoxic activity, the MTT [3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide] assay was conducted. The chemical analysis of the extract was performed by LC/MS (liquid chromatography coupled to mass spectrometry). The minimum bactericidal concentration (MBC) of T. islandicus’ intracellular red pigmented extract (IRPE) for E. coli ATCC 25922 and S. aureus ATCC 25923 was 1000 μg/ml. The minimum inhibitory concentration (MIC) for E. coli was 250 μg/mL and for S. aureus 500 μg/mL, respectively, whereas for C. tropicalis ATCC 1369 was 62.5 μg/mL. IC50 for breast cancer cell line (MCF-7) was 45.43 ± 1.657 μg / mL. The major compounds present in the extract were: Luteoskyrin (1) and N-GABA-PP-V (6-[(Z)-2-Carboxyvinyl]-N-GABA-PP-V) (2). The results show that IRPE from T. islandicus TI01 has a prominent antibacterial activity against E. coli and S. aureus, making this pigment interesting for development of new food colorants and/or conservative agents, since these bacteria are food-borne pathogens.