Neuraminidase Inhibitors from marine‐derived actinomycete Streptomyces seoulensis

• Published in: Journal of applied microbiology Vol. 114; no. 4; pp. 1046 - 1053
• Main Authors: Jiao, R.H., Xu, H., Cui, J.T., Ge, H.M., Tan, R.X.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01-04-2013; Oxford University Press
• Subjects: Animals; Benzodiazepines - chemistry; Benzodiazepines - isolation & purification; Biological and medical sciences; Clostridium perfringens - enzymology; Enzymes; Fundamental and applied biological sciences. Psychology; Lactones - chemistry; Lactones - isolation & purification; Magnetic Resonance Spectroscopy; Marine; marine‐derived actinomycete; Metabolites; Microbiology; Molecular Structure; Neuraminidase - antagonists & inhibitors; neuraminidase inhibitors; Penaeidae; Penaeidae - microbiology; RNA, Ribosomal, 16S - genetics; Shellfish; Streptomyces - chemistry; Streptomyces - genetics; Streptomyces seoulensis; Streptomycetaceae; Enzyme; Applied microbiology; marine-derived actinomycete; Streptomyces; Actinomycetales; Glycosylases; Marine environment; Streptomyces seoulensis; Glycosidases; Exo-α-sialidase; Bacteria; Hydrolases; Actinomycetes; Inhibitor; neuraminidase inhibitors
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.12136

Aims
This work was performed to characterize new secondary metabolites with neuraminidase (NA) inhibitory activity from marine actinomycete strains.
Methods and Results
An actinomycete strain IFB‐A01, capable of producing new NA inhibitors, was isolated from the gut of shrimp Penasus orientalis and identified as Streptomyces seoulensis according to its 16S rRNA sequence (over 99% homology with that of the standard strain). Repeated chromatography of the methanol extract of the solid‐substrate culture of S. seoulensis IFB‐A01 led to the isolation of streptoseolactone (1), and limazepines G (2) and H (3). The structures of 1–3 were determined by a combination of IR, ESI‐MS, 1D (1H and 13C NMR, and DEPT) and 2D NMR experiments (HMQC, HMBC, 1H‐1H COSY and NOESY). Compounds 1–3 showed significant inhibition on NA in a dose‐dependent manner with IC50 values of 3·92, 7·50 and 7·37 μmol l−1, respectively.
Conclusions
This is the first report of two new (1 and 2) and known (3, recovered as a natural product for the first time in the work) NA inhibitors from the marine‐derived actinomycete S. seoulensis IFB‐A01.
Significance and Impact of the Study
The three natural NA inhibitors maybe of value for the development of drug(s) necessitated for the treatment of viral infections.