Chemistry of two new leprarioid lichens from Sri Lanka

Abstract

The hexane and dichloromethane extracts of the lichen Leproloma sipmanianum, collected from Beragala, contained the compounds, atranorin 1, βsitosterol 2, (+)-usnic acid 3, zeorin 4 and tritetracontylpentanoate 5 while the methanol extract furnished the triterpenoid 3β-acetoxyfern-9(ll)- ene 6. In addition to compounds 1-5, the lichen powder yielded glyceryl trilinolate 7 and 3, 6-dimethyl-2-hydroxy-4-methoxybenzoic acid 8. Chromatography of the lichen powder of Lepraria atrotomentosa led to the isolation of five compounds, including compounds 1-4 along with methyl-β-orcinolcarboxylate 9. (+)-Usnic acid exhibited potent antitermite activity against a common pest of tea at low elevations, Glyptotermes dilatatus. 3,6-Dimethyl-2-hydroxy-4-methoxybenzoic acid 8 showed moderate larvicidal activity against the second instar larvae ot Aedes aegypti.