BIOLOGICAL-ACTIVITY OF POLYKETIDE PIGMENTS PRODUCED BY THE FUNGUS MONASCUS

The biological activity of the pigment extracts from Monascus purpureu s included their antibiotic action not only against bacteria but also against some species of yeasts and filamentous fungi, as well as embry otoxicity and teratogenicity. These activities depended on the presenc e of the orange component (monascorubrin and rubropunctatin). The form ation of these compounds was influenced by the composition of the cult ure medium and by cultivation of the fungus: when amino acids, peptide s or proteins were available during cultivation, as in the case of sol id-state cultivation on rice, wheat or pearl barley or submerged culti vation with an organic nitrogen source, the bioactive compounds were c onverted into inactive complexes and, to a lesser extent, into purple pigments (monascorubramine and rubropunctamine) which retained some bi ological activity. The toxicity of the orange pigments may reside in t he same reaction as their detoxication, i.e. in their binding to cellu lar NH-groups.