REVIEW Monascus secondary metabolites: production and biological activity Petra Patakova Received: 29 August 2012 / Accepted: 3 November 2012 / Published online: 20 November 2012 Ó Society for Industrial Microbiology and Biotechnology 2012 Abstract The genus Monascus, comprising nine species, can reproduce either vegetatively with filaments and con- idia or sexually by the formation of ascospores. The most well-known species of genus Monascus, namely, M. pur- pureus, M. ruber and M. pilosus, are often used for rice fermentation to produce red yeast rice, a special product used either for food coloring or as a food supplement with positive effects on human health. The colored appearance (red, orange or yellow) of Monascus-fermented substrates is produced by a mixture of oligoketide pigments that are synthesized by a combination of polyketide and fatty acid synthases. The major pigments consist of pairs of yellow (ankaflavin and monascin), orange (rubropunctatin and monascorubrin) and red (rubropunctamine and monasco- rubramine) compounds; however, more than 20 other col- ored products have recently been isolated from fermented rice or culture media. In addition to pigments, a group of monacolin substances and the mycotoxin citrinin can be produced by Monascus. Various non-specific biological activities (antimicrobial, antitumor, immunomodulative and others) of these pigmented compounds are, at least partly, ascribed to their reaction with amino group-con- taining compounds, i.e. amino acids, proteins or nucleic acids. Monacolins, in the form of b-hydroxy acids, inhibit hydroxymethylglutaryl-coenzyme A reductase, a key enzyme in cholesterol biosynthesis in animals and humans. Keywords Monascus Á Red yeast rice Á Pigments Á Monacolin K Á Citrinin Introduction In Asian countries (China, Japan, Thailand, Indonesia, Tai- wan, Philippines), filamentous fungi of the genus Monascus have been used for centuries for the production of food components, natural pigments and food supplements with positive effects on human health. The most famous product is Monascus-fermented rice, also known under a variety of other names, including red rice, red yeast rice, ang-kak, anka, ankak, angkhak, angquac and beni-koji [67]. A particular fungal species, under given conditions, can produce a variety of secondary metabolites (pigments, citrinin, monacolin K and others) that are usually charac- terized by a polyketide structure and biological activity. At the present time, research in this field is mainly focused on the isolation and characterization of new secondary metabolites [1, 10, 17, 26–28, 30, 63, 72, 82, 86, 89], as well as on the determination of their biological activities [1, 27, 35, 41, 63]. The main aim of this review is to collate available knowledge on Monascus secondary metabolites, with emphasis on their production and the spectra of their biological activities. The fungus Monascus The genus Monascus belongs to the phylum Eumycota, subphylum Ascomycotina, class Plectomycetes, order Eurotiales, family Monascaceae and currently comprises nine species, i.e. M. floridanus, M. pallens, M. pilosus, M. purpureus, M. ruber, M. sanguineus, M. eremophilus, M. lunisporas and M. argentinensis, for which there are a number of synonyms [77]. Most Monascus species are homothallic, teleomorphic fungi; an anamorph of the genus Monascus is Bazipetospora. P. Patakova (&) Department of Biotechnology, Institute of Chemical Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic e-mail: petra.patakova@vscht.cz 123 J Ind Microbiol Biotechnol (2013) 40:169–181 DOI 10.1007/s10295-012-1216-8