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J. Venom. Anim. Toxins incl. Trop. Dis.

V.21, 2015.

Original paper - ISSN 1678-9199.

 

Antimycobacterial and cytotoxicity activity of microcystins

 
Daniela Fernandes Ramos 1, Alexandre Matthiensen 2, Wilson Colvara 3, Ana Paula Souza de Votto 4, Gilma Santos Trindade 4, Pedro Eduardo Almeida da Silva 1, João Sarkis Yunes 5

1 Research Center in Medical Microbiology, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul State, Brazil

2 Brazilian Corporation of Agricultural Research (Embrapa), Concórdia, Santa Catarina State, Brazil

3 School of Chemistry and Food, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul State, Brazil

4 Graduation Program in Physiological Sciences, Institute of Biological Sciences, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul State, Brazil

5 Laboratory of Cyanobacteria and Phycotoxins, Institute of Oceanography, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul State, Brazil

 

ABSTRACT

 

Background

The present work aimed to evaluate the antimycobacterial activity and cytotoxicity of Microcystis aeruginosa toxins, the MC-LR variant and purified extract of [D-Leu1] microcystin-LR.

 

Methods

The antimicrobial activity of M. aeruginosa extract and microcystin was evaluated by resazurin microtiter assay against Mycobacterium tuberculosis, M. terrae, M. chelonae and M. kansasii. The cytotoxicity assay was performed by trypan blue exclusion against the HTC cell line.

 

Results

Antimicrobial activity was observed in the hexanic extract of M. aeruginosa (RST 9501 strain) against M. tuberculosis, including sensitive and resistant strains with minimal inhibitory concentrations (MIC) between 1.93 μM and 0.06 μM. The high activity of M. aeruginosa hexanic extract could be attributed to the major presence of the toxins MC-LR and [D-Leu1] MC-LR that showed activity at MIC between 53 and 0.42 μM against tested mycobacterial strains. Even at the highest concentration tested, no toxicity of M. aeruginosa extracts was identified against HTC cells.

 

Conclusions

These preliminary results suggest that [D-Leu1] MC-LR is a promising candidate for the development of a new antimycobacterial agent.

 

Key words: Mycobacteria; Antimycobacterial agents; Cytotoxic activity; Microcystins

 

Received: August 25, 2014; Accepted: March 6, 2015; Accepted: March 20, 2015

 

Corresponding author: Daniela F Ramos daniferamos@gmail.com

 

Competing interests

The authors declare that they have no competing interests.

 

Authors’ contributions

DFR and PEAS conceived the study and carried out the antimycobacterial activity tests. AM, WC and JSY carried out the preparation and analysis of Microcystis aeruginosa extracts. APSV and GST conducted cytotoxicity assays. All authors read and approved the final manuscript.