Synthesis of the lichen depsides pseudocyphellarin A and B

Elix, JA; Lajide, L.

doi:10.1071/ch9842153

Cited by 8 publications

(5 citation statements)

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“…We do not know the efficiency of the individual substances in L. amplissima as feeding deterrents. However, pseudocyphellarin is chemically related to nephroarctin and phenarctin (Elix & Lajide 1984), which deters grazing on Nephroma arcticum (Asplund & Gauslaa 2009).…”

Section: Discussionmentioning

confidence: 99%

Gastropod grazing shapes the vertical distribution of epiphytic lichens in forest canopies

et al. 2009

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Summary1. Species composition and biomass of epiphytic lichens varies along a complex environmental gradient from the ground to the top of the forest canopy. It is not known if this gradient, considered to be shaped by succession (age of bark surface) and climatic factors, is also influenced by invertebrate grazing. 2. To investigate the grazing hypothesis, the natural height ranges of four old-forest Lobaria species on tree trunks were quantified. These large foliose epiphytes with different secondary chemistry were transplanted onto Fraxinus excelsior trunks 0.5, 3 and 6 m above-ground in five broad-leaved deciduous forests in southern Norway. After 4.5 months of exposure to natural climbing gastropods, grazing was quantified. 3. Grazing pressure strongly increased with increasing proximity to the ground. At all heights, gastropods clearly preferred Lobaria scrobiculata followed by L. amplissima. Lobaria pulmonaria, highest in carbon-based secondary compounds (CBSCs), and L. virens, nearly deficient in CBSCs, were both much less grazed. Therefore, CBSCs cannot explain the preferences. According to existing literature the stictic acid complex, present in L. pulmonaria and L. scrobiculata, represents a herbivore defence when occurring in quantities as high as those in L. pulmonaria. The identity of the strong defence in the CBSC-deficient L. virens is unknown. 4. Gastropods' preference for these epiphytes mirrors the distribution of the lichens in nature. The highly palatable L. scrobiculata occurs mainly in localities with low gastropod abundance such as boreal forests and on bark with slightly lower pH. Lobaria amplissima occurs in gastropod-rich localities, but above the lower parts of the trunk. Lobaria pulmonaria and L. virens frequently grow down to a level of < 1 m above the ground. 5. Synthesis. Our results suggest that climbing gastropods play a role in determining the lower distribution limit of epiphytic lichens along a vertical canopy gradient and influence the spatial pattern of susceptible lichen species. By grazing lichens in a species-specific way, gastropods can shape epiphytic communities in broad-leaved deciduous forests.

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Section: Discussionmentioning

confidence: 99%

Gastropod grazing shapes the vertical distribution of epiphytic lichens in forest canopies

et al. 2009

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“…India. 1495 that para-depsides could be readily converted into the corresponding diphenyl ether via an intramolecular Smiles rearrangement (Elix et al, 1984). The present work is part of a project concerned with the synthesis of diphenyl ethers and their analogues.…”

Section: Commentmentioning

confidence: 99%

Methyl 2,6-Dihydroxy-4-(2-hydroxy-4,6-dimethoxy-3-methylbenzoyloxy)-3-methylbenzoate

Chantrapromma¹,

Sortiruk²,

Chantrapromma³

et al. 1998

Acta Crystallogr C

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“…Phenyl ether derivatives which turned out to be the major components in this study were previously obtained from cultured lichen mycobionts [10][14] [30], lichens [31] [32],s ponges [33][34],a nd the fungi Aspergillus sp. [ 11 -13][21 -23][ [35][36][37][38][39][40], Penicillium sp.…”

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confidence: 99%

Identification and Biological Evaluation of Secondary Metabolites from the Endolichenic Fungus Aspergillus versicolor

Zhou

Zhu

et al. 2015

Chemistry & Biodiversity

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A chemical investigation of the endolichenic fungus Aspergillus versicolor (125a), which was found in the lichen Lobaria quercizans, resulted in the isolation of four novel diphenyl ethers, named diorcinols F-H (1-3, resp.) and 3-methoxyviolaceol-II (4), eight new bisabolane sesquiterpenoids, named (-)-(R)-cyclo-hydroxysydonic acid (5), (-)-(7S,8R)-8-hydroxysydowic acid (6), (-)-(7R,10S)-10-hydroxysydowic acid (7), (-)-(7R,10R)-iso-10-hydroxysydowic acid (8), (-)-12-acetoxy-1-deoxysydonic acid (9), (-)-12-acetoxysydonic acid (10), (-)-12-hydroxysydonic acid (11), and (-)-(R)-11-dehydrosydonic acid (12), two new tris(pyrogallol ethers), named sydowiols D (13) and E (14), and fifteen known compounds, 15-29. All of the structures were determined by spectroscopic analyses, and a number of them were further identified through chemical transformations and electronic circular dichroism (ECD) calculations. Preliminary bioassays of these isolates for the determination of their inhibitory activities against the fungus Candida albicans, and their cytotoxicities against the human cancer cell lines PC3, A549, A2780, MDA-MB-231, and HEPG2 were also evaluated.

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Synthesis of the lichen depsides pseudocyphellarin A and B

Cited by 8 publications

References 0 publications

Gastropod grazing shapes the vertical distribution of epiphytic lichens in forest canopies

Gastropod grazing shapes the vertical distribution of epiphytic lichens in forest canopies

Methyl 2,6-Dihydroxy-4-(2-hydroxy-4,6-dimethoxy-3-methylbenzoyloxy)-3-methylbenzoate

Identification and Biological Evaluation of Secondary Metabolites from the Endolichenic Fungus Aspergillus versicolor

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