Secondary Metabolite Profiling of Species of the Genus Usnea by UHPLC-ESI-OT-MS-MS

Abstract

Lichens are symbiotic associations of fungi with microalgae and/or cyanobacteria, which are considered among the slowest growing organisms, with strong tolerance to adverse environmental conditions. There are about 400 genera and 1600 species of lichens and those belonging to the Usnea genus comprise about 360 of these species. Usnea lichens have been used since ancient times as dyes, cosmetics, preservatives, deodorants and folk medicines. The phytochemistry of the Usnea genus includes more than 60 compounds which belong to the following classes: depsides, depsidones, depsones, lactones, quinones, phenolics, polysaccharides, fatty acids and dibenzofurans. Due to scarce knowledge of metabolomic profiles of Usnea species (U. barbata, U. antarctica, U. rubicunda and U. subfloridana), a study based on UHPLC-ESI-OT-MS-MS was performed for a comprehensive characterization of their secondary metabolites. From the methanolic extracts of these species a total of 73 metabolites were identified for the first time using this hyphenated technique, including 34 compounds in U. barbata, 21 in U. antarctica, 38 in U. rubicunda and 37 in U. subfloridana. Besides, a total of 13 metabolites were not identified and reported so far, and could be new according to our data analysis. This study showed that this hyphenated technique is rapid, effective and accurate for phytochemical identification of lichen metabolites and the data collected could be useful for chemotaxonomic studies.

UPLC–MS/MS quantitative analysis and structural fragmentation study of five Parmotrema lichens from the Eastern Ghats

“…Alternatively, study of lichen compounds by usual LC-MS techniques [10] or direct spectroscopic analysis [11][12][13][14][15][16][17] offers a helpful tool for chemotaxonomic determination of compounds and dereplication strategies [18,19]. Accurate techniques as UPLC-HRMS are now available to identify a number of compounds [20][21][22][23] but protocols are not still standardized.…”

Evaluation of the Cytotoxic Activity of the Usnea barbata (L.) F. H. Wigg Dry Extract

“…These lichen secondary metabolites, structurally close, exhibit many biological actions : antibacterial, antiviral, antioxidant, anti-inflammatory, cytotoxic, and antitumor [16].Usnea barbata (L.) F. H. Wigg. is a fruticose lichen belonging to the Parmeliaceae family [17] who lives in the coniferous forests of Europe and North America, and for thousands of years, it has been used in the traditional medicine to treat various conditions [18].The phenolic compounds [19] identified in this species were mainly depsides, depsidones, lipids, diphenylether derivatives, and dibenzofurans [20]. The most important secondary metabolite, common to all species of the genus Usnea, is usnic acid-C 18 H 16 O 7 -[2,6-diacetyl-7,9-dihydroxy-8,9bdimethyldibenzofuran-1,3(2H,9bH)-dione], which is a phenolic compound with dibenzofuran structure [21] (Figure 1).…”

“…The phenolic compounds [19] identified in this species were mainly depsides, depsidones, lipids, diphenylether derivatives, and dibenzofurans [20]. The most important secondary metabolite, common to all species of the genus Usnea, is usnic acid-C 18 H 16 O 7 -[2,6-diacetyl-7,9-dihydroxy-8,9bdimethyldibenzofuran-1,3(2H,9bH)-dione], which is a phenolic compound with dibenzofuran structure [21] (Figure 1).…”

Carbon Consumption Patterns of Microbial Communities Associated with Peltigera Lichens from a Chilean Temperate Forest

“…In conclusion, the lichen thallus provides an adequate microhabitat that selects certain bacterial lineages [ 26 ], probably through the production of metabolites [ 42 , 71 , 72 ] which could select specific lineages in order to carry out defined functions as part of a multispecies symbiosis [ 25 ]. Several studies have characterized the biologically active metabolites produced by lichens (e.g., antibiotic, antiviral, anti-inflammatory, analgesic, cytotoxic, etc.)…”