Microbial Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 12 No. 4, Issue of October 15, 2009
© 2009 by Pontificia Universidad Católica de Valparaíso -- Chile Received February 9, 2009 / Accepted September 12, 2009
DOI: 10.2225/vol12-issue4-fulltext-9

Novel antimicrobial secondary metabolites from a Penicillium sp. isolated from Brazilian cerrado soil

Philippe Petit
Departamento de Química, ICEx
Universidade Federal de Minas Gerais
Belo Horizonte, MG, Brazil

Esther M. F. Lucas
Departamento de Química, ICEx
Universidade Federal de Minas Gerais and
Departamento de Química
Universidade Federal de Lavras
MG, Brazil

Lucas M. Abreu
Departamento de Química, ICEx
Universidade Federal de Minas Gerais
Belo Horizonte, MG, Brazi

Ludwig H. Pfenning
Departamento de Fitopatologia
Universidade Federal de Lavras
Lavras, MG, Brazil

Jacqueline A. Takahashi*
Departamento de Química, ICEx
Universidade Federal de Minas Gerais
Av. Antônio Carlos 6627, Pampulha
Belo Horizonte, MG, Brazil
Tel: 55 31 3409 5754
Fax: 55 31 3409 5700
E-mail: jat@qui.ufmg.br

*Corresponding author

Financial support: Conseil General de la Guadeloupe (grants to Dr. P. Petit), FAPEMIG (Brazil), CNPq (Brazil) and IFS (Sweden).

Keywords: antibacterial activity, cerrado, naphthalenoids, Penicillium, secondary metabolites


CYA: czapek yeast extract agar
DEPT: distortionless enhancement by polarization transfer
DMF: dimethylformamide
EIMS: electron-ionization mass spectrometry
EtOAc: ethylacetate
G25N: 25% glycerol nitrate agar
HMBC: heteronuclear multiple bond correlation
HMQC: heteronuclear multiple quantum coherence
MEA: malt extract agar
MIC: minimum inhibitory concentration
NMR: nuclear magnetic resonance
NOESY: nuclear overhauser and exchange spectroscopy
TLC: thin layer chromatography

Abstract   Full Text

The morphological features of a Penicillium, isolated from Brazilian cerrado soil, were characterized and showed to be distinctly different from all well-defined Penicillium species. Chemical and biological investigation on the ethyl acetate extract of this Penicillium isolate resulted in the isolation of three new naphthalenoids: a major metabolite, methyl 6-acetyl-4-methoxy-5,7,8-trihydroxynaphthalene-2-carboxylate and two minor ones, methyl 6-acetyl-4-methoxy-7,8-dihydroxynaphthalene-2-carboxylate and methyl 6-acetyl-4-methoxy-5,8-dihydroxynaphthalene-2-carboxylate. Their structures were determined based on their mono and bidimensional nuclear magnetic resonance data. Acetyl, allyl and methoxyl derivatives of the major metabolite were prepared in order to establish structure-activity relation. Antimicrobial activity of the major natural product and its semi-synthetic derivatives was screened by macro dilution methodology and the corresponding minimum inhibitory concentrations were determined. Natural secondary metabolite methyl 6-acetyl-4-methoxy-5,7,8-trihydroxynaphthalene-2-carboxylate, isolated in a very high yield (0.3175 mg.L-1) showed to be the most active compound, possessing expressive activity against Candida albicans (minimum inhibitory concentration (MIC) 32 µg/mL), Listeria monocitogenes and Bacillus cereus (MIC 64 µg/mL for both).

Supported by UNESCO / MIRCEN network