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

Abstract

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.