Investigation of antimicrobial and protease-inhibitory activity from cultured cyanobacteria

Abstract

A culture collection of cyanobacteria has been established at the University of Illinois at Chicago. This collection includes marine, terrestrial, and freshwater strains and contains representatives of the five orders of cyanobacteria: Chroococcales, Pleurocapsales, Oscillatoriales, Nostocales, and Stigonematales. In this study, extracts from a subset of 61 strains, 16 marine and 45 freshwater/terrestrial, were evaluated against three current protease targets, i.e. 20S proteasome and two SARS viral proteases, two important bacterial targets, i.e. Mycobacterium tuberculosis and Bacillus anthracis, and in the Artemia salina toxicity assay. In total, extracts of 12 strains possessed significant levels of activity in one or more targets. The overwhelming majority of active extracts (11 of 12) were from either freshwater or terrestrial forms of cyanobacteria, with the greater part of these (9 of 12) being heterocyst-forming strains. These results further support the use of cultured cyanobacteria as a source of biologically active natural products.

Keywords::

• Anthrax
• antimicrobial
• brine shrimp
• cyanobacteria
• protease inhibition
• proteasome
• SARS
• tuberculosis

Acknowledgements

We thank Kiira Ratia, Dr. Valerie Grum-Tokars, Molly Bishop, and Sara Forrester of the Center for Pharmaceutical Biotechnology (Department of Medicinal Chemistry and Pharmacognosy, UIC College of Pharmacy) for performing the PLpro (K.R.), 3CLpro (V.G-T.), and B. anthracis assays (M.B. and S.R.). We also thank Baojie Wan of the Institute for Tuberculosis Research (UIC College of Pharmacy) for performing the TB assays.

This work was supported by NIH Grant 1 R01 GM075856 and the University of Illinois at Chicago Spring 2006 Provost Award to G.C.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.