Microorganisms are an inexhaustible gold mine of new natural compounds

Abstract

Natural compounds produced by microorganisms have greatly contributed to the improvement of human health. Actinomycete and fungal strains are known to produce various secondary metabolites in their culture broths. The Kitasato Ōmura-Drug Discovery Group has found over 500 new compounds from these microorganisms. The production strains have been preserved by a long-term preservation method as Kitasato Microbial Library (KML).

The physicochemical properties of compounds produced by the preserved strains and fresh isolates were analyzed, and compared with a database. Subsequently, predicted new compounds were purified from culture broths and their structures were determined by NMR and MS. 35 compounds have been discovered by this approach, called Physicochemical screening. A compound, designated iminimycin, containing an iminium ion was discovered from the culture broth of Streptomyces griseus OS-3601. This KML strain has been stored for a long time as a streptomycin producing strain. Named trehangelin was discovered from rare actinomycete Plolymorphospora rubra K07-0510 isolated from the roots of orchid collected from Iriomote Island, Japan. Trehangelin A, the main compound, binds angelic acids to the 3, 3’ positions of trehalose. It has been found that the compound showed cytoprotective effect and accumulation of procollagen type I C-peptide, and further research is currently in progress.

It is shown that microorganisms are an inexhaustible gold mine of new natural compounds.