RESUMO
Acetone extracts of the two common epiphytes lichens Usnea florida and Flavoparmelia caperata have been evaluated for their antimicrobial activities against Staphylococcus aureus, Candida albicans and Aspergillus brasiliensis. The dibenzofuran derivative (+)-usnic acid (1) was the main metabolite in these two species. Thamnolic (5), evernic (6), physodic (7) and 3-hydroxyphysodic acids (8) were isolated from U. florida, as well as 5,7-dihydroxy-6-methylphtalide (2) which was newly identified in this Genus. Protocetraric (3) and caperatic acids (4) and ergosterol peroxide (9) are usually biosynthezised by F. caperata. Antibacterial activity was determined for the four main compounds against Staphylococcus aureus using bioautography and broth dilution method. Minimal inhibitory concentrations of usnic acid, caperatic acid and protocetraric acid were comprised between 7.25 and 12.5 µg/mL.
Assuntos
Anti-Infecciosos/farmacologia , Parmeliaceae/química , Acetona/química , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Aspergillus/efeitos dos fármacos , Benzofuranos/análise , Benzofuranos/farmacologia , Candida albicans/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/análise , Compostos Heterocíclicos com 3 Anéis/farmacologia , Líquens/química , Líquens/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Parmeliaceae/metabolismo , Metabolismo Secundário , Staphylococcus aureus/efeitos dos fármacosRESUMO
Covering: up to 2016.When looking for dibenzofuran in the biochemical databases, most papers and reviews deal with pollutants and polychlorinated dibenzofurans like dioxins. But dibenzofurans are also biosynthetized by a wide diversity of organisms in nature. Even if dibenzofurans from natural sources represent a small class of secondary metabolites, compared to flavonoids, xanthones or terpenoids, they are often endowed with interesting biological properties which have been recently described. This review provides an update on papers describing dibenzofurans from lichens, ascomycetes and cultured mycobionts. Other sources, such as basidiomycetes, myxomycetes or plants produce sporadically interesting dibenzofurans in terms of structures and activities.
Assuntos
Ascomicetos/química , Dibenzofuranos/isolamento & purificação , Líquens/química , Dibenzofuranos/química , Dibenzofuranos/farmacologia , Dioxinas/química , Dioxinas/isolamento & purificação , Dioxinas/farmacologia , Estrutura Molecular , Mixomicetos/químicaRESUMO
Bioassay-guided fractionation of an extract of the lichen Cladonia incrassata against Staphylococcus aureus led to a novel compound, 1,5-dihydroxy-2,4,6-trichloro-7-methylxanthone (1), along with six known compounds: (-)-usnic acid (2), didymic acid (3), condidymic acid (4), squamatic acid (5), thamnolic acid (6), and prasinic acid (7). Didymic, condidymic, and prasinic acids were isolated for the first time from C. incrassata. Didymic, condidymic, and (-)-usnic acids were active against S. aureus (a minimum inhibitory concentration of 7.5 µg/mL).
