The Monascus fungi have traditionally been used in Asia for food coloring. Unfortunately, the most well-known species, Monascus purpureus, very often produce mycotoxin citrinin in addition to pigments, which poses a significant problem for the use of pigments in foods. There is a step in pigment biosynthesis where a side chain of five or seven carbons is attached to the tetraketide, the product of polyketide synthase, resulting in the formation of pigments in pairs. Further, it is still unclear whether pigment and citrinin biosyntheses are related or independent. Therefore, this study is focused on the relationship between pigment and citrinin production and pigment analogues that differ in side chain length, all evaluated by the Spearman correlation test. To generate sufficient data, Monascus purpureus DBM 4360 was cultivated with different carbon and nitrogen sources and under osmotic stress induced by glucose and/or sodium chloride. The study reveals a very strong correlation between the production of five- and seven-carbon side chain pigments under all culture conditions tested for all three groups, yellow, orange, and red pigments. The correlation between pigments and citrinin depended on the group assessed and ranged from fair to very strong. While the coordinated synthesis of pigment analogues in pairs has been clearly confirmed, the relationship between pigment and citrinin production was unfortunately neither confirmed nor refuted and must be the subject of further research.

• Klíčová slova
• Monascus purpureus, citrinin, pigments, regulation of secondary metabolites biosynthesis, stress conditions,
• MeSH
• biologické pigmenty * chemická syntéza   MeSH
• citrinin * biosyntéza   chemie   MeSH
• dusík metabolismus   MeSH
• kultivační techniky MeSH
• Monascus * chemie   růst a vývoj   metabolismus   MeSH
• osmotický tlak fyziologie   MeSH
• uhlík metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické pigmenty * MeSH
• citrinin * MeSH
• dusík MeSH
• uhlík MeSH

The fungus Monascus is a well-known source of secondary metabolites with interesting pharmaceutical and nutraceutical applications. In particular, Monascus pigments possess a wide range of biological activities (e.g. antimicrobial, antioxidant, anti-inflammatory or antitumoral). To broaden the scope of their possible application, this study focused on testing Monascus pigment extracts as potential photosensitizing agents efficient in antimicrobial photodynamic therapy (aPDT) against bacteria. For this purpose, eight different extracts of secondary metabolites from the liquid- and solid-state fermentation of Monascus purpureus DBM 4360 and Monascus sp. DBM 4361 were tested against Gram-positive and Gram-negative model bacteria, Bacillus subtilis and Escherichia coli and further screened for ESKAPE pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. To the bacterial culture, increasing concentration of extracts was added and it was found that all extracts showed varying antimicrobial activity against Gram-positive bacteria in dark, which was further increased after irradiation. Gram-negative bacteria were tolerant to the extracts' exposure in the dark but sensitivity to almost all extracts that occurred after irradiation. The Monascus sp. DBM 4361 extracts seemed to be the best potential candidate for aPDT against Gram-positive bacteria, being efficient at low doses, i.e. the lowest total concentration of Monascus pigments exhibiting aPDT effect was 3.92 ± 1.36 mg/L for E. coli. Our results indicate that Monascus spp., forming monascuspiloin as the major yellow pigment and not-forming mycotoxin citrinin, is a promising source of antimicrobials and photoantimicrobials.

• MeSH
• antibakteriální látky * farmakologie   chemie   MeSH
• biologické pigmenty farmakologie   MeSH
• biologické přípravky farmakologie   chemie   MeSH
• fotochemoterapie MeSH
• fotosenzibilizující látky farmakologie   chemie   MeSH
• grampozitivní bakterie účinky léků   účinky záření   MeSH
• komplexní směsi farmakologie   chemie   MeSH
• mikrobiální testy citlivosti * MeSH
• Monascus * chemie   metabolismus   MeSH
• mycelium * chemie   účinky záření   účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• red yeast rice MeSH Prohlížeč