Improved Chromatographic Method for the Purification of Phenolic Constituents of the Lichen Parmotrema tinctorum (Nyl.) Hale.

A method for the separation and fractionation of the phenolic
compounds atranorin, methyl orsenillate, orsenillic acid, and
lecanoric acid from the lichen Parmotrema tinctorum (Nyl.) Hale
(P. tinctorum) using thin-layer chromatography (TLC) and column
chromatography, respectively, is described. TLC of lichen extract
with an acid-free developing solvent on silica gel G containing 1 %
oxalic acid is carried out, and the compounds are visualized as
yellow spots when sprayed with 10% sulfuric acid in methanol
followed by heating at 110°C. For the fractionation of pure lichen
compounds, column chromatography is carried out using silica gel
impregnated with 1 % oxalic acid. To our knowledge, it is also the
first report on the isolation and characterization of methyl
orsenillate and orsenillic acid from P. tinctorum (Nyl.) Hale.