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Fraxitoxin, a New Isochromanone Isolated from Diplodia fraxini
Author(s) -
Cimmino Alessio,
Maddau Lucia,
Masi Marco,
Linaldeddu Benedetto T.,
Pescitelli Gennaro,
Evidente Antonio
Publication year - 2017
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201700325
Subject(s) - tyrosol , canker , chemistry , fraxinus , circular dichroism , absolute configuration , botany , nuclear chemistry , stereochemistry , phenols , organic chemistry , biology
A new isochromanone, named fraxitoxin, was isolated together with (–)‐mellein and tyrosol from liquid cultures of Diplodia fraxini , a pathogen involved in the etiology of canker and dieback disease of Fraxinus spp. in Europe. It was characterized as 5‐methoxy‐3‐methylisochroman‐1‐one using spectroscopic methods (essentially NMR and HR‐EI‐MS). Its absolute configuration ( R ) at C(3) was assigned by electronic circular dichroism (ECD) measurements and calculations. Phytotoxic activity of the compound was evaluated on ash, cork and holm oak leaves at concentration of 1 mg/ml by the leaf‐puncture assay. Interestingly, fraxitoxin caused necrotic lesions only on ash leaves.