Sch 36605, a novel anti-inflammatory compound. Taxonomy, fermentation, isolation and biological properties

Streptomyces-Derived Metabolites with Potential Photoprotective Properties-A Systematic Literature Review and Meta-Analysis on the Reported Chemodiversity

Sun overexposure is associated with the development of diseases that primarily affect the skin, which can lead to skin cancer. Among the main measures of photoprotection is the use of sunscreens. However, there is currently concern about the reported harmful effects to both humans and the environment due to several of the sunscreen ingredients available on the market. For this reason, the search for and development of new agents with photoprotective properties is required. In searching for these metabolites, researchers have turned their attention to microbial sources, especially the microbiota in unusual hostile environments. Among the diverse microorganisms available in nature, Actinobacteria and specifically Streptomyces, have been shown to be a source of metabolites with various biological activities of interest, such as antimicrobial, antitumor and immunomodulator activities. Herein, we present the results of a systematic review of the literature in which Streptomyces isolates were studied as a source of compounds with photoprotective properties. A meta-analysis of the structure-property and structure-activity relationships of those metabolites identified in the qualitative analysis phase was also carried out. These findings indicate that Streptomyces are a source of metabolites with potential applications in the development of new, safe and more eco-friendly sunscreens.

Current progress on nucleoside antibiotics

Structure and biological activity of thirty-six new nucleoside antibiotics which appeared after the 1988 review are described. New synthetic analogs of neplanocin and oxetanocin are also described with special emphasis on their antiviral activities. New biosynthetic findings on nikkomycins, blasticidin S, and griseolic acid are also reviewed.

Detection of novel secondary metabolites

The study of antibiotics and other fermentation products has shown that a seemingly unlimited number of compounds with diverse structures are produced by microorganisms. The continued high rate of discovery of new chemical entities, in the light of the abundance of microbial products already described, is due to creative screening procedures that incorporate such features as the emphasis on unusual microorgnaisms, their special propagation and fermentation requirements, supersensitive and highly selective assays, genetic engineering both for the biosynthesis of new compounds and in the development of screening systems, early in vivo evaluation, improved isolation techniques, modern procedures for structure determination, computer-assisted identification, and an efficient multidisciplinary approach. This review focuses on the genesis and development of the gamut of methodologies that have led to the successful detection of the wide variety of novel secondary metabolites that include antibacterial, antigungal, antiviral and antitumour antibiotics, enzyme inhibitors, pharmacologically and immunologically active agents, products useful in agriculture and animal husbandry, microbial regulators, and other compounds for which no bioactive role has yet been found.

Photodiode array detection of peptide-nucleoside antibiotics

The discrimination within fermentation matrices of some structurally related peptide-nucleosides is vastly simplified by coupling photodiode array detection to high-performance liquid chromatography (HPLC). Blasticidin S analogues and other closely related nucleosides can easily be discriminated with on-line photodiode array spectral acquisition (PDA). From the combined HPLC-PDA evaluation of the fermentation filtrate from culture broth 83-2245, two blasticidin S type compounds, Sch 36605 and Sch 36606 could be detected. Mildiomycin, a structurally related nucleoside produced from ATCC culture 31120, could be detected during preliminary isolation without an authentic reference for comparison. Fast atom bombardment mass spectroscopic evaluations and mass-analysed ion kinetic energy spectra of these nucleosides confirmed their respective identities.