Isolation of the Antibacterial Agent Viridiol from the Mangrove Endophytic Fungus Hypocrea virens, as Monitored by a Biologic Assay Against Escherichia coli and NMR Spectroscopy

Title:Isolation of the Antibacterial Agent Viridiol from the Mangrove Endophytic Fungus Hypocrea virens, as Monitored by a Biologic Assay Against Escherichia coli and NMR Spectroscopy

Volume: 6 Issue: 4

Author(s): Fernanda Luiza Souza Sebastianes*, Angela Maria Montes Peral Valente, Elisangela Fabiana Boffo, Antonio Gilberto Ferreira, Itamar Soares Melo, Luiz Alberto Beraldo Moraes, Joao Lucio Azevedo, Aline Aparecida Pizzirani-Kleiner and Paulo Teixeira Lacava

Affiliation:

• Department of Genetics, “Luiz de Queiroz” College of Agriculture, University of Sao Paulo, Av. Padua Dias, 11, 83, 13400-970, Piracicaba, SP,Brazil

Keywords: Endophytic fungi, Hypocrea virens, NMR spectroscopy, Trichodema, viridiol, biological assay.

Abstract: Background: Endophytic fungi are considered a source of novel activities, compounds and biotechnological processes with great and underexplored potential. The aims of this paper were: a) to evaluate the antibiotic activity of mangrove endophytic fungi against the human pathogens Staphylococcus aureus, Salmonela typhi and Escherichia coli and against the phytopathogen Xantomonas axonopodis citri; b) to elucidate the structure of the antibiotic produced by the endophytic fungus Hypocrea virens strain 89(3), using spectroscopic methods, mainly 1D and 2D NMR, as well as mass spectra and comparison with previously published data.

Methods: The selection of the endophytic fungi producer of antibiotics was based on agar piece method. The pure substance (viridiol) was obtained by carrying out biological tests with the extract and its fractions against pathogenic bacteria (Escherichia coli), and this study was monitored by NMR spectroscopy. Viridiol was isolated from the mangrove endophytic fungus H. virens, which was obtained from branches of Avicennia nitida. The structure of the compound was elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopy and confirmed by mass spectrometry.

Results: In bioassays, compound viridiol showed antimicrobial activity against Escherichia coli, with an MIC of 64 µg/ml. The antibiotic-producing strain was identified as H. virens using internal transcribed spacer (ITS) sequence data. The spectroscopic methods employed were an efficient means of elucidating the structure of antibiotic viridiol.

Conclusion: The isolation of a bioactive substance using 1H NMR monitoring was highly successful because it showed step by step the spectral signals concerning the bioactive substance from crude extract to pure substance. This is the first report of antimicrobial activity by viridiol against E. coli, a medically important pathogen.

Cite this article as:

Souza Sebastianes Luiza Fernanda*, Montes Peral Valente Maria Angela, Boffo Fabiana Elisangela, Ferreira Gilberto Antonio, Melo Soares Itamar, Beraldo Moraes Alberto Luiz, Azevedo Lucio Joao, Pizzirani-Kleiner Aparecida Aline and Lacava Teixeira Paulo, Isolation of the Antibacterial Agent Viridiol from the Mangrove Endophytic Fungus Hypocrea virens, as Monitored by a Biologic Assay Against Escherichia coli and NMR Spectroscopy, Current Biotechnology 2017; 6 (4) . https://dx.doi.org/10.2174/2211550105666160223215928