Aqabamycins, Rare Nitro Maleimides and other Novel Metabolites from Microorganisms; Generation and Application of an HPLC-UV-ESI MS/MS Database

Abstract

The battle to improve the quality of life by finding cures against diseases and to extend the life expectancy of mankind is still one of the priorities in natural products chemistry. Al-though the exploration of natural products has already made available a high number of bio-logical active compounds, in addition to increasing resistance, cancer as well as many vicious infectious diseases continue to destroy life. The discovery of new secondary metabolites with large spectra of activity needs new alternative sources and screening methods. So, terrestrial and marine bacteria and fungi, which have a special adaptability as well as a survival capacity in extreme habitats, were investigated. In the present work 12 strains were studied. To enable the isolation and structure elucidation of new and preferably biologically active secondary metabolites from marine and terrestrial bacteria, several steps needed to be completed such as biological assays, chemical screening and the dereplication through HPLC-MS/MS for the detection of interesting compounds in crude extracts. Among the 96 compounds isolated here, 49 had new and even novel structures. In view of the structural diversity (Aqabamycin, Euphamycin, Iguanen, Moyopomycin, Celastramycin, Silamycin, and Heramide) and the broad range of activities exhibited by these compounds it is right to say that the study of mi-croorganisms as source of new antibiotics is still very promising. The second part of this work was to complete our HPLC-UV-ESI MS/MS database with all compounds previously isolated in our group, to facilitate the dereplication of known as well as new metabolites from crude extracts. This screening method is a suitable tool for the rapid dereplication of secondary metabolites as well as for the evaluation and rationalisation of feeding experiments and media optimisation.