Lecanoric acid, a secondary lichen substance with antioxidant properties from Umbilicaria antarcticain maritime Antarctica (King George Island).
Antimicrobial activity of fumarprotocetraric acid,
lecanoric acid, protocetraric acid and stictic acid isolated from different species of lichen.
As part of our study of lichens from the Cerrado biome in Mato Grosso do Sul state, Midwest Brazil, the present article reports novel findings on the radical-scavenging activity of two depsides (atranorin and lecanoric acid), five depsidones (protocetraric, hypostictic, norstictic, salazinic, and psoromic acids), usnic acid, lichexanthone, and derivatives of 9'-O-alkyl protocetraric acid.
The depsides atranorin (1) and lecanoric acid (3), the depsidones protocetraric (2), salazinic (6), hypostictic (7) norstictic (8), and psoromic (9) acids, the xanthone lichexanthone (5), and usnic acid (4) isolated from lichen species were evaluated for their free-radical-scavenging activity towards 2,2'-diphenyl-1-picrylhydrazyl (DPPH, a stable free radical) at 0.1 and 0.3 mM concentrations.
Concentrations of
lecanoric acid in some Parmelia species, such as P.
hossei Atranorin -
Lecanoric acid - Usnic acid + Sekikaic acid + Salanizic acid - Terpenoids + Tannins + Saponins - Flavonoids - Steroids - Table 2: Antifungal activity of solvent extracts of R.
For example, antioxidant activity was found for
lecanoric acid, salazinic acid, stictic acid, usnic acid (Luo et al.
The depsides (atranorin, diffractaic and
lecanoric acids), depsidones (protocetraric, salazinic, hypostictic and norstictic acids), xanthones (lichexanthone and secalonic acid), and usnic acid, as well seven orsellinic acid esters, five salazinic acid 8',9'-0-alkyl derivatives and four lichexanthone derivatives, were evaluated for their activity against Mycobacterium tuberculosis.
Another supportive report also emphasizes the correlation between antioxidative capacity and phenolic constituents, particularly methyl orsenillate, orsenillic acid, atranorin and
lecanoric acid (Jayaprakasha and Rao, 2000).