A secondary metabolite with in vitro radical scavenging activity from endolichenic fungus Daldinia eschscholzii found in lichen, Parmotrema sp. in Sri Lanka

Endolichenic fungi, an unexplored group of microorganisms, are a promising source of bioactive compounds. Secondary metabolites were isolated from the chloroform fraction of crude ethyl acetate extract of endolichenic fungus Daldinia eschscholzii inhabiting the lichen, Parmotrema sp. in Sri Lanka. Two pure compounds, 1 and 2 were isolated and the structures were identified using 1H-, 13C-, 2D- nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) data. Compound 1 did not show any radical scavenging activity in DPPH assay. Compound 2, identified as 8-methoxynaphthalen-1-ol showed strong radical scavenging ability in the DPPH assay with a half maximal inhibitory concentration (IC50) of 10.2 ± 5.8 µg/ mL. The activity of compound 2 was higher than that of the standard, butylated hydroxy toluene (BHT).