Phenolic Constituents from the Lichen Parmotrema stuppeum (Nyl.) Hale and Their Antioxidant Activity

Lichen, Parmotrema stuppeum (P. stuppeum ) was successively extracted with benzene and acetone. Both the extracts were fractionated on 1 % oxalic acid impregnated silica gel column to obtain four phenolic com pounds. The structures of com pounds were identified by H and C NMR spectra as methyl orsenillate, orsenillic acid, atranorin and lecanoric acid respectively. Antioxidant activity of benzene extract, acetone extract and isolated com pounds w ere evaluated in a β-carotene-linoleate model system. The pure com pounds showed moderate antioxidant activity. This is the first report on the isolation and characterisation of com pounds from the lichen P. stuppeum as well as on their antioxidant activity.