Lobaric Acid Research Articles

Sublobaric Acid and Oxolobaric Acid, Two New Depsidones from the Lichen Anzia hypoleucoides

The depsidones sublobaric acid (8-hydroxy-3-methoxy-11-oxo-1-propanoyl-6-pentyl-11H-dibenzo[b,e][1,4]- dioxepin-7-carboxylic acid) (6) and oxolobaric acid (1-(1′,4′-dioxopentyl)-8-hydroxy-3-methoxy-11-oxo-6-pentyl-11H-dibenzo[b,e][1,4]dioxepin-7-carboxylic acid) (7) have been isolated from the lichenAnzia hypoleucoides together with atranorin, chloroatranorin, divaricatic acid and lobaric acid (1). The structure of compounds (6) and (7) followed from a combination of spectroscopic data.

AUSTRALIAENA STREIMANNII, A NEW GENUS AND SPECIES IN THE PHYSCIACEAEFROM TROPICAL AUSTRALASIA

The genus Australiaena(lichenized Ascomycetes, Physciaceae) with the single species A. streimanniisp. nov. is described as new from tropical Australasia. Morphologically it is characterized by crustose thalli with an often radiate-plicate margin, ascospores with a type-B ontogeny, and filiform spermatia. The chemistry of this taxon is diverse (lobaric acid, conlobaric acid, xanthones, gyrophoric acid, lecanoric acid, 5- O-methylhiascic acid, perlatolic acid), and three chemotypes are distinguished.

Inhibitory effects of the lichen metabolite lobaric acid on arachidonate metabolism in vitro

An extract containing phenolic constituents of the lichen Stereocaulon alpinum was shown to exhibit potent in vitro inhibitory effects on arachidonate 5-lipoxygenase from porcine leucocytes. The active component has been identified as the orcinol depsidone lobaric acid (1), which shows dose-dependent inhibitory effects on the enzyme, with an IC(50) value of 7.3 μM. Lobaric acid exhibits approximately 4-fold in vitro selectivity for 5-lipoxygenase as compared to cyclooxygenase.

Siphula elixii, a new lichen from Tasmania and New Zealand

Abstract The new lichen, Siphula elixii Kantvilas, is described from Tasmania and New Zealand. It is related to S. fragilis (J.D. Hook. & Taylor) J. Murray but is characterised chiefly by the presence of lobaric acid, which is recorded from the genus Siphula for the first time.

Chemical Constituents of the Lichen Stereocaulon azoreum

Column chromatography of the acetone extract of the lichen Stereocaulon azoreum afforded several substances identified by chemical and spectral means; α-amyrin, lupeol, taraxerol, ursolic acid, ergosterol peroxide, brassicasterol, cerevisterol, stictic acid and an acetone-condensation derivative, lobaric acid. Furthermore atranorin, methyl β-orsellinate, atranol and, for the first time from the genus Stereocaulon, cryptostictic acid and the dibenzofuran, strepsilin were isolated.

Japewia Subaurifera, A New Lichen Genus and Species From North-West Europe and Western North America

AbstractThe genus Japewia Tønsb. is introduced to accommodate three species including J. subaurifera Muhr & Tønsb. sp. nov. based on material from Norway, Sweden, Finland, Scotland, Canada (British Columbia) and U.S.A. (Washington). This species is closely related to Lecidea tornoensis Nyl. but is distinguished in being sorediate and by the production of lobaric acid (accessory) and acetone-soluble pigments. It grows on bark of deciduous and coniferous trees. Lecidea carrollii Coppins & P. James and L. tornoensis Nyl. are transferred to Japewia.

Zuordnung der 1H-NMR-Spektren von Depsiden, Depsidonen, Depsonen und Dibenzofuranen aus Flechten durch NOE-Differenzspektroskopie / Assignment of 1H NMR Spectra of Depsides, Depsidones, Depsones and Dibenzofurans from Lichens by NOE Difference Spectroscopy

The 1H NMR spectra of the following lichen substances have been correlated by NOE difference spectroscopy: atranorin, barbatic acid, diffractaic acid, nephroarctin, perlatolic acid, planaic acid methyl ester, pseudocyphellarin A, sphaerophorin (depsides), hypoprotocetraric acid, lobaric acid, pannarin, physodalic acid, psoromic acid, stictic acid (depsidones), picrolichenic acid (depsone), di-O-methyl-pannaric acid dimethylester, pannaric acid, porphyrilic acid, schizopeltic acid, strepsilin, and usnic acid (dibenzofurans).

Systematics of the Usnea fragilescens aggregate and its distribution in Scandinavia

Systematics and taxonomy of Usnea cornuta, U. flammea and U. fragilescens are discussed. The morphology, chemistry and distribution of these species in Europe are described and a first attempt is made to provide a key for the erect‐bushy to subpendant and sorediate species in Scandinavia. Compounds reported in this aggregate include lobaric acid (new to the genus). U. flammea is new for Scandinavia. U. constrictula, U. inflate, U. intexla and U. subpectinata are reduced to synonymy with U. cornuta, U. dalmatica and U. rupestris to synonymy with U. flammea, U. glaucescens to synonymy with U. hirta and the new combination U. fragilescens var. mollis is proposed.

Secondary Compounds Following Northsouth Transplantation of Three Lichen Species

AbstractWide north-south transplants were made with three lichen species, Parmelia cumberlandia, Cladonia turgida and Stereocaulon saxarile. The objective was to determine whether thallus chemistry would be altered due to wide geographic displacement of thallus segments from the control locations. Significant quantitative variation in microchemistry was observed among thalli of P. cumberlandia and among those of C. turgida, but there were no qualitative or quantitative effects on the lichen products, usnic acid, atranorin, constictic, stictic, norstictic, fumarprotocetraric and lobaric acids, due to transplantation.