Synthesis of natural pulvinic
acids based on a [3 + 2] cyclization-Suzuki cross-coupling strategy.
Most known lichen substances are phenolic compounds, anthraquinones, dibenzofurans, depsides, depsidones, depsones, gamma lactones and pulvinic
Some authors believe that epiphytic lichens protect the trees they grow on, for they are at less risk from wood-rotting fungi because the lichens produce a series of specific acids, such as usnic acid and pulvinic
acid, which show antibiotic activity against wood-destroying fungi.
Most lichen substances are phenolic compounds, dibenzofurans, depsides, depsidones, lactones and pulvinic
Several lichen metabolites of various chemical classes, including the aliphatic acids, depsides and depsidones, dibenzofurans, diterpenes, anthraquinones, naphthoquinones, usnic acids, pulvinic
acids, xanthones, and epidithiopiperazinediones have been reported with various biological activities such as cytotoxic, fungicidal, antimicrobial, antioxidant, and anti-inflammatory (Muller 2001).
Lichens, symbiotic associations of a fungus and one or more algae, produce several classes of phenolic compounds, including: depsides, depsidones, usnic acids, dibenzofuranes, xanthones, anthraquinones, in addition to pulvinic
acid derivatives and aliphatic acids.