Xanthones from the cultured lichen mycobionts of Pyrenula japonica and Pyrenula pseudobufonia

Tanahashi, Takao; Takenaka, Yasuhiro; Ikuta, Yuki; Tani, Kaori; Nagakura, Naotaka; Hamada, Nobuyuki

doi:10.1016/s0031-9422(99)00235-6

Cited by 29 publications

(10 citation statements)

References 9 publications

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“…On the other hand, cultures of spore-derived lichen mycobionts under osmotically stressed conditions are capable of producing certain lichen substances such as anthraquinones (Takenaka et al, 2002) or novel metabolites, e.g., isofuranonaphthoquinones (Yamamoto et al, 2002). We have recently isolated and characterized new xanthones from the cultured mycobionts of Pyrenula japnica and Pyrenula pseudobufonia (Tanahashi et al, 1999;Takenaka et al, 2000). In continuation of our studies on cultured lichen mycobionts (Takenaka et al, 2003), we cultivated the spore-derived mycobionts of Pyrenula sp.…”

Section: Introductionmentioning

confidence: 56%

Three isocoumarins and a benzofuran from the cultured lichen mycobionts of Pyrenula sp.

et al. 2004

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Section: Introductionmentioning

confidence: 56%

Three isocoumarins and a benzofuran from the cultured lichen mycobionts of Pyrenula sp.

et al. 2004

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“…For the last twenty years, only three research teams reported on such structures to the best of our knowledge. At first, a series of five xanthones isolated from aposymbiotically-cultured mycobionts of Pyrenula japonica and P. bufonica [37,38], a suite of prenylated xanthone heterosides from Umbilicaria proboscidea along with their acylated homologues [39,40], and later cladoxanthone A from Cladonia incrassata [41]. A salient feature regarding these structures is that none of them display a canonical substitution pattern relating them to either the norlichexanthone/lichexanthone or ravenelin subtype.…”

Section: Resultsmentioning

confidence: 99%

DP4-Assisted Structure Elucidation of Isodemethylchodatin, a New Norlichexanthone Derivative Meager in H-Atoms, from the Lichen Parmotrema tsavoense

et al. 2019

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A phytochemical investigation of the foliose lichen Parmotrema tsavoense (Krog and Swinscow) Krog and Swinscow (Parmeliaceae) resulted in the isolation of a new trichlorinated xanthone, isodemethylchodatin. The structure elucidation of this new norlichexanthone derivative proved tricky owing to proton deficiency, and to the lack of NMR data of closely related analogues. The structure of this compound was determined based on an integrated interpretation of 13C-NMR chemical shifts, MS spectra, and DP4-based computational chemistry was also performed to provide an independent and unambiguous validation of the determined structure. Isodemethylchodatin represents the first chlorinated lichexanthone/norlichexanthone derivative bearing a methoxy group at C-5.

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“…The presence of a COOCH 3 group at C-8 of the xanthone ring is unusual, since most xanthones isolated from higher plants presents a methyl group at C-3, while the xanthones isolated from lichens have a methyl group at C-8 position [ 15 ]. Previous investigators have proposed that lichen xanthones are biosynthesized by cyclization of a single, linear polyketide chain [ 16 ]. It has been proposed that Leiothrix xanthones are biosynthetically related to naphthopyranones isolated from species of the Paepalanthus genus (Eriocaulaceae) [ 12 ].…”

Section: Resultsmentioning

confidence: 99%

Chemical Constituents of the Methanolic Extract of Leaves of Leiothrix spiralis Ruhland and Their Antimicrobial Activity

et al. 2011

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Chemical fractionation of the methanolic extract of leaves of Leiothrix spiralis Ruhland afforded the flavonoids luteolin-6-C-β-D-glucopyranoside (1), 7-methoxyluteolin-6-C-β-D-glucopyranoside (2), 7-methoxyluteolin-8-C-β-D-glucopyranoside (3), 4′-methoxyluteolin-6-C-β-D-glucopyranoside (4), and 6-hydroxy-7-methoxyluteolin (5), and the xanthones 8-carboxymethyl-1,5,6-trihydroxy-3-methoxyxanthone (6), 8-carboxy-methyl-1,3,5,6-tetrahydroxyxanthone (7). Methanolic extract, fractions, and isolated compounds of the leaves of L. spiralis were assayed against Gram-positive (Staphylococcus aureus, Bacillus subtilis and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella setubal and Helicobacter pylori) and fungi (the yeasts Candida albicans, C. tropicalis, C. krusei and C. parapsilosis). We observed the best minimum inhibitory concentration values for the methanolic extract against Candida parapsilosis, for the fraction 5 + 6 against Gram-negative bacteria E. coli and P. aeruginosa, and compound 7 against all tested Candida strains. The methanolic extract contents suggest that this species may be a promising source of compounds to produce natural phytomedicines.

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Xanthones from the cultured lichen mycobionts of Pyrenula japonica and Pyrenula pseudobufonia

Cited by 29 publications

References 9 publications

Three isocoumarins and a benzofuran from the cultured lichen mycobionts of Pyrenula sp.

Three isocoumarins and a benzofuran from the cultured lichen mycobionts of Pyrenula sp.

DP4-Assisted Structure Elucidation of Isodemethylchodatin, a New Norlichexanthone Derivative Meager in H-Atoms, from the Lichen Parmotrema tsavoense

Chemical Constituents of the Methanolic Extract of Leaves of Leiothrix spiralis Ruhland and Their Antimicrobial Activity

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