Bioactive metabolites from the fungus Nectria galligena, the main apple canker agent in Chile.
The phytopathogenic fungus Nectria galligena Bres. is the most common canker disease agent of hardwood trees. The terpenoids colletochlorin B, colletorin B, ilicicolin C, E, and F, as well as the phytotoxin alpha,beta-dehydrocurvularin have been isolated from liquid cultures of N. galligena obtained from the xylem of infected apple trees in central Chile. Ilicicolin C and F and alpha,beta-dehydrocurvularin were active against Pseudomonas syringae with IC50 values of 28.5, 28.5, and 14.2 microg/mL, respectively, in the same range as streptomycin and penicillin G (11 and 15 microg/mL, respectively). All of the compounds showed moderate inhibitory activity toward the enzymes acetylcholinesterase (AChE) and beta-glucuronidase. The most active enzyme inhibitors were colletochlorin B and ilicicolin C and E, with IC50 values of 30-36 microg/mL in the AChE assay and 32-43 microg/mL in the beta-glucuronidase test. All of the chlorinated compounds showed some toxicity toward human lung fibroblasts, with IC50 values in the range of 64-120 microg/mL. alpha,beta-Dehydrocurvularin proved to be the most toxic compound, showing IC50 values less than 12 microg/mL. The effect of the isolated compounds on seed germination and radicle and epicotyl growth was assessed in lettuce and millet seeds. At 100 and 200 microg/disk, alpha,beta-dehydrocurvularin significantly reduced radicle length and epicotyl growth in Lactuca sativa. This is the first report on the occurrence of colletochlorin B, colletorin B, ilicicolin C, E, and F, as well as alpha,beta-dehydrocurvularin associated to N. galligena.
Gutiérrez
Margarita
M
Laboratorio de Química de Productos Naturales, Instituto de Química de Recursos Naturales, Departamento de Ciencias Básicas Biomédicas, Facultad de Ciencias de la Salud, and Laboratorio de Fitopatología, Universidad de Talca, Talca, Chile.
Theoduloz
Cristina
C
Rodríguez
Jaime
J
Lolas
Mauricio
M
Schmeda-Hirschmann
Guillermo
G
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D017077:Culture Media, Conditioned; D005347:Fibroblasts / Q000187:drug effects; D005659:Fungicides, Industrial / Q000494:pharmacology; D005966:Glucuronidase / Q000037:antagonists & inhibitors; D006540:Herbicides / Q000494:pharmacology; D006801:Humans; D006999:Hypocreales / Q000378:metabolism*; D008168:Lung; D027845:Malus / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D013729:Terpenes / Q000302:isolation & purification* / Q000494:pharmacology; D015025:Zearalenone / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D002800:Cholinesterase Inhibitors; D017077:Culture Media, Conditioned; D005659:Fungicides, Industrial; D006540:Herbicides; D013729:Terpenes; C013914:dehydrocurvularin; D015025:Zearalenone; D005966:Glucuronidase