RESUMEN
In the present investigation, methanol, chloroform and petrol ether extracts from the lichen Toninia candida (Weber) Th. Fr, Catillariaceae, were assayed for their antioxidant activity. The phenolic composition of the extracts was determined by HPLC-UV analysis. The predominant phenolic compound in all the extracts was depsidone, norstictic acid. All the tested extracts of T. candida contain, besides norstictic acid, atranorin, stictic, protocetraric and usnic acid, but in different amounts and relations. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, chelating activity and inhibitory activity towards lipid peroxidation. This is the first report of chemical composition and antioxidant antimicrobial activity of the lichen Toninia candida.