New bioactive secondary metabolites, called abenquines, were found in the fermentation broth of Streptomyces sp. strain DB634, which was isolated from the soils of the Chilean highland of the Atacama Desert. They are composed of an amino acid linked to an N-acetyl-aminobenzoquinone. Isolation of the abenquines (1-4), their structure elucidation by NMR analysis and MS, as well as the kinetics of their production are presented. The abenquines show inhibitory activity against bacteria, dermatophytic fungi and phosphodiesterase type 4b. The amino acid attached to the quinone is relevant to the enzyme inhibitory activity. The Journal of Antibiotics (2011) INTRODUCTIONThe Northern Chilean highlands of the Atacama Desert comprise a number of extreme habitats, including permanent arid soils exposed to very high UV irradiation and strong fluctuations in temperature, various types of salt lakes differing in salinity and mineral salts composition and also geothermal-driven hot springs and geysers. These habitats make this area extraordinarily interesting for studies of microbial communities adapted to extreme environmental conditions. Previous studies have shown that salt lakes of this area harbor unique communities of anoxygenic phototrophic bacteria 1 and cyanobacteria. 2 Recently, we have isolated a number of actinobacteria from arid soils of the Atacama Desert and characterized them in regard to their potential to synthesize secondary metabolites. In this study, we present the secondary metabolite profile of one of the isolated Streptomyces strains.

Micromonospora sp. strain DB620 was isolated from a Wadden Sea sediment sample collected near Büsum (Germany) and is closely related (99% 16S-rRNA gene sequence similarity) to Micromonospora coxensis strain MTCC8093. It produced a new polyene dicarboxylic acid named diacidene (1) and in addition a derivative of chorismic acid, the known 3-[(1-carboxyvinyl)oxy]benzoic acid. The structure elucidation of 1 was achieved by applying different 1D and 2D NMR techniques as well as mass spectrometry and UV spectroscopy.

Micromonospora sp. strain DB620 was isolated from a Wadden Sea sediment sample collected near Büsum (Germany) and is closely related (99% 16S-rRNA gene sequence similarity) to Micromonospora coxensis strain MTCC8093. It produced a new polyene dicarboxylic acid named diacidene (1) and in addition a derivative of chorismic acid, the known 3-[(1-carboxyvinyl)oxy]benzoic acid. The structure elucidation of 1 was achieved by applying different 1D and 2D NMR techniques as well as mass spectrometry and UV spectroscopy.

Abenquines A-D: Aminoquinone Derivatives Produced by Streptomyces sp. Strain DB634. -Abenquines A, B1, B2, C and D (Ia)-(Ie), resp., show inhibitory activity against bacteria, dermatophytic fungi and phosphodiesterase type 4b. -(SCHULZ, D.; BEESE, P.; OHLENDORF, B.; ERHARD, A.; ZINECKER, H.; DORADOR, C.; IMHOFF*, J.; J. Antibiot. 64 (2011) 12, 763-768, http://dx.