Production of nocardicyclins by clinical isolates of Nocardia pseudobrasiliensis and in vivo antitumor activity of the antibiotic

Natural Products from Nocardia and Their Role in Pathogenicity

Nocardia spp. are filamentous Actinobacteria of the order Corynebacteriales and mostly known for their ability to cause localized and systemic infections in humans. However, the onset and progression of nocardiosis is only poorly understood, in particular the mechanisms of strain-specific presentations. Recent genome sequencing has revealed an extraordinary capacity for the production of specialized small molecules. Such secondary metabolites are often crucial for the producing microbe to survive the challenges of different environmental conditions. An interesting question thus concerns the role of these natural products in Nocardia-associated pathogenicity and immune evasion in a human host. In this review, a summary and discussion of Nocardia metabolites is presented, which may play a part in nocardiosis because of their cytotoxic, immunosuppressive and metal-chelating properties or otherwise vitally important functions. This review also contains so far unpublished data concerning the biosynthesis of these molecules that were obtained by detailed bioinformatic analyses.

Production of bioactive compounds by actinomycetes and their antioxidant properties

An actinomycete was isolated from mangrove soil collected from Nellore region of Andhra Pradesh, India, and screened for its ability to produce bioactive compounds. The cultural, morphological, and biochemical characters and 16S rRNA sequencing suggest that the isolated strain is Nocardiopsis alba. The bioactive compounds produced by this strain were purified by column chromatography. The in vitro antioxidant capacity of the isolated compounds (fractions) was estimated and fraction F2 showed very near values to the standard ascorbic acid. The potential fraction obtained by column chromatography was subjected to HPLC for further purification, then this purified fraction F2 was examined by FTIR, NMR, and mass spectroscopy to elucidate its chemical structure. By spectral data, the structure of the isolated compound was predicted as “(Z)-1-((1-hydroxypenta-2,4-dien-1-yl)oxy)anthracene-9,10-dione.”

A Synthesis of l-Vancosamine Derivatives from Non-Carbohydrate Precursors by a Short Sequence Based on the Marshall, McDonald, and Du Bois Reactions

[reaction: see text] The carbamate-protected l-vancosamine glycal, viewed as a universal precursor for vancosamine derivatives, was prepared by a short scheme based on diastereoselective addition of an allenyl stannane to a lactaldehyde ether, the tungsten-catalyzed alkynol cycloisomerization, and the rhodium-catalyzed C-H insertion of a carbamate nitrogen. This sequence is a prototype for a new and efficient strategy for the synthesis of 3-amino sugar derivatives. The key intermediate was elaborated to the silyl ether of N,N-dimethyl vancosamine glycal.