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Structure and Chemical Analysis of Major Specialized Metabolites Produced by the Lichen Evernia prunastri
Author(s) -
Staples Richard,
LaDuca Robert L.,
Roze Ludmila V.,
Laivenieks Maris,
Linz John E.,
Beaudry Randolph,
Fryday Alan,
Schilmiller Anthony L.,
Koptina Anna V.,
Smith Benjamin,
Trail Frances
Publication year - 2020
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.201900465
Subject(s) - chemistry , usnic acid , crystal structure , sodium , lichen , moiety , stereochemistry , crystallography , organic chemistry , botany , biology
We performed comparative profiling of four specialized metabolites in the lichen Evernia prunastri , collected at three different geographic locations, California and Maine, USA, and Yoshkar Ola, Mari El, Russia. Among the compounds produced at high concentrations that were identified in all three specimens, evernic acid, usnic acid, lecanoric acid and chloroatranorin, evernic acid was the most abundant. Two depsidones, salazinic acid and physodic acid, were detected in the Yoshkar‐Ola collection only. The crystalline structure of evernic acid (2‐hydroxy‐4‐[(2‐hydroxy‐4‐methoxy‐6‐methylbenzoyl)oxy]‐6‐methylbenzoate) (hmb) revealed two crystallographically and conformationally distinct hmb anions, along with two monovalent sodium atoms. One hmb moiety contained an exotetradentate binding mode to sodium, whereas the other exhibited an exohexadentate binding mode to sodium. Embedded edge‐sharing {Na 2 O 8 } n sodium‐oxygen chains connected the hmb anions into the full three‐dimensional crystal structure of the title compound. The crystal used for single‐crystal X‐ray diffraction exhibited non‐merohedral twinning. The data suggest the importance of the acetyl‐polymalonyl pathway products to processes of maintaining integrity of the lichen holobiont community.