benzofurans and lecanoric-acid

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

Topics: Benzofurans; Hydroxybenzoates; Lichens; Models, Molecular; Salicylates

Lichen secondary metabolites can function as allelochemicals and affect the development and growth of neighboring bryophytes, fungi, vascular plants, microorganisms, and even other lichens. Lichen overgrowth on bryophytes is frequently observed in nature even though mosses grow faster than lichens, but there is still little information on the interactions between lichens and bryophytes.In the present study, we used extracts from six lichen thalli containing secondary metabolites like usnic acid, protocetraric acid, atranorin, lecanoric acid, nortistic acid, and thamnolic acid. To observe the influence of these metabolites on bryophytes, the moss Physcomitrella patens was cultivated for 5 weeks under laboratory conditions and treated with lichen extracts. Toxicity of natural mixtures of secondary metabolites was tested at three selected doses (0.001, 0.01, and 0.1 %). When the mixture contained substantial amounts of usnic acid, we observed growth inhibition of protonemata and reduced development of gametophores. Significant differences in cell lengths and widths were also noticed. Furthermore, usnic acid had a strong effect on cell division in protonemata suggesting a strong impact on the early stages of bryophyte development by allelochemicals contained in the lichen secondary metabolites.Biological activities of lichen secondary metabolites were confirmed in several studies such as antiviral, antibacterial, antitumor, antiherbivore, antioxidant, antipyretic, and analgetic action or photoprotection. This work aimed to expand the knowledge on allelopathic effects on bryophyte growth.

Topics: Allelopathy; Benzofurans; Bryopsida; Cell Division; Cell Size; Germ Cells, Plant; Heterocyclic Compounds, 3-Ring; Hydroxybenzoates; Lichens; Plant Extracts; Salicylates; Secondary Metabolism

To investigate the chemical constituents of the lichen plants Parmelia tinctorum and Parmelia nimandairana collected from Meng Mountain in Shandong province.. Various chromatographic techniques were used to isolate and purify the constituents and their structures were elucidated by means of spectral evidence and physiochemical properties.. Four compounds were isolated from Parmelia tinctorum and identified as: lecanoric acid (I), evernic acid (II), ethyl orsellinate (III) and 3,5-dihydroxytoluene (IV). Two compounds were isolated from Parmelia nimandairana and identified as: usnic acid (V) and salazinic acid (VI).. Compounds V and VI are isolated from Parmelia nimandairana for the first time.

Topics: Benzofurans; China; Chromatography, High Pressure Liquid; Hydroxybenzoates; Lactones; Lichens; Molecular Structure; Resorcinols; Salicylates; Solvents

Lecanoric acid (1), orsellinic acid methyl ester (2), orcinol (3), and usnic acid (4) were isolated from the lichen Parmelia subrudecta, collected on Palma of the Canary Islands, Spain. Compounds 1, 2, 3, and 4 were purified by solvent extraction, silica gel column chromatography, and preparative high-performance liquid chromatography (HPLC) consecutively. The structures of the four compounds were elucidated by one- and two-dimensional nuclear magnetic resonance (NMR) experiments and mass spectrometric investigations. These compounds showed activity against important gram-positive and gram-negative pathogens like mycobacteria and multiresistant staphylococci. This activity is combined with antiproliferative activity and cytotoxicity.

Topics: Anti-Infective Agents; Antineoplastic Agents; Bacteria; Bacterial Infections; Benzofurans; Cell Line, Tumor; Cell Proliferation; Humans; Lichens; Magnetic Resonance Spectroscopy; Molecular Structure; Neoplasms; Resorcinols; Salicylates; Spectrometry, Mass, Electrospray Ionization