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Antifungal Cyclic Lipopeptides from Bacillus amyloliquefaciens Strain BO5A

Romano, Adriana, Vitullo, Domenico, Senatore, Mauro, Lima, Giuseppe, Lanzotti, Virginia
Journal of natural products 2013 v.76 no.11 pp. 2019-2025
Aspergillus niger, Bacillus amyloliquefaciens, Botrytis cinerea, Fusarium oxysporum, Penicillium italicum, Trichoderma harzianum, amino acids, biological control, chemical degradation, chemical structure, fatty acids, fractionation, fungi, lipopeptides, mass spectrometry, metabolites, nuclear magnetic resonance spectroscopy, pathogens
A bioassay-guided fractionation of Bacillus amyloliquefaciens strain BO5A afforded the isolation of two new cyclic lipopeptides (1 and 2) as the major lipid constituents (>60%) of the CHCl₃–MeOH (2:1) extract. The chemical structures of the isolated metabolites were elucidated by spectroscopic methods, including 1D and 2D NMR spectroscopy, mass spectrometry (MS), secondary ion mass spectrometry (MS1, MS2), and chemical degradation. The compounds are members of the surfactins family and are based on a heptapeptide chain composed by Glu-Val-Leu-Val-Asp-Leu-Leu. Its N-terminal end is N-acylated by an (R)-3-hydroxy fatty acid with linear alkyl chains of 16:0 and 15:0 (1 and 2, respectively). The 3-hydroxyl group closes a 25-membered lactone ring with the carboxylic group of the C-terminal amino acid. The isolated compounds were tested for their inhibitory activity against the four pathogenic fungi Fusarium oxysporum, Aspergillus niger, Botrytis cinerea, and Penicillium italicum and the biocontrol fungus Trichoderma harzianum. Compound 2 displayed activity against all tested pathogens.