Five new secondary metabolites from Monascus purpureus-fermented Hordeum vulgare and Sorghum bicolor

Potential antiplatelet aggregation metabolites from the discarded sorghum (Sorghum bicolor L.) root

Sorghum (Sorghum bicolor L.) is the fifth largest crop in the world and has potential health benefits, but vast quantities of sorghum roots are discarded after harvest. Based on the previous antiplatelet aggregation for this species, two new multi-substituted 3H-indole alkaloids sorghumine A (1) and sorghumine B (2), together with 14 known compounds (3-16), were found from the water extract of sorghum roots. Compounds 1-2 were identified by analyzing their spectroscopic data and physic and chemical properties, and the absolute configuration was further determined by electronic circular dichroism (ECD) analysis and calculations. 1-2, 4, 6-8 and 13-15 showed significant inhibition of platelet aggregation induced by adenosine diphosphate. 2-4, 6-9 and 11 showed significant inhibition of platelet aggregation induced by collagen. 4-6, 8, 10-11 and 16 showed significant inhibition on platelet aggregation induced by thrombin. Furthermore, molecular docking showed that active compounds can bind to P2Y12 and COX-1 receptors in platelet.

Overexpression of Monacolin K Biosynthesis Genes in the Monascus purpureus Azaphilone Polyketide Pathway

Monascus purpureus is an important food and drug microbial resource through the production of a variety of secondary metabolites, including monacolin K, a well-recognized cholesterol-lowering agent. However, the high production costs and naturally low contents of monacolin K have restricted its large-scale production. Thus, in this study we sought to improve the production of monacolin K in M. purpureus through overexpression of four genes ( mokC, mokD, mokE, and mokI). Four overexpression strains were successfully constructed by protoplast electric shock conversion, which resulted in a 234.3%, 220.8%, 89.5%, and 10% increase in the yield of monacolin K, respectively. The overexpression strains showed clear changes to the mycelium surface with obvious folds and the spores with depressions, whereas the pBC5 mycelium had a fuller structure with a flatter surface. Further investigation of these strains can provide the theoretical basis and technical support for the development of functional Monascus varieties.

De Novo RNA Sequencing and Transcriptome Analysis of Monascus purpureus and Analysis of Key Genes Involved in Monacolin K Biosynthesis

Monascus purpureus is an important medicinal and edible microbial resource. To facilitate biological, biochemical, and molecular research on medicinal components of M. purpureus, we investigated the M. purpureus transcriptome by RNA sequencing (RNA-seq). An RNA-seq library was created using RNA extracted from a mixed sample of M. purpureus expressing different levels of monacolin K output. In total 29,713 unigenes were assembled from more than 60 million high-quality short reads. A BLAST search revealed hits for 21,331 unigenes in at least one of the protein or nucleotide databases used in this study. The 22,365 unigenes were categorized into 48 functional groups based on Gene Ontology classification. Owing to the economic and medicinal importance of M. purpureus, most studies on this organism have focused on the pharmacological activity of chemical components and the molecular function of genes involved in their biogenesis. In this study, we performed quantitative real-time PCR to detect the expression of genes related to monacolin K (mokA-mokI) at different phases (2, 5, 8, and 12 days) of M. purpureus M1 and M1-36. Our study found that mokF modulates monacolin K biogenesis in M. purpureus. Nine genes were suggested to be associated with the monacolin K biosynthesis. Studies on these genes could provide useful information on secondary metabolic processes in M. purpureus. These results indicate a detailed resource through genetic engineering of monacolin K biosynthesis in M. purpureus and related species.