In vitro radical-scavenging activity, toxicity against A. salina, and nmr profiles of extracts of lichens collected from Brazil and Antarctica

Extracts of six lichen species collected from Brazil and Antarctica were investigated for their potential toxicity and radical-scavenging properties. The composition of the extracts was investigated using TLC and NMR, leading to identification of atranorin (1), along with salazinic (2), barbatic (3), alpha-alectoronic (4), alpha-collatolic (5), cryptochlorophaeic (6), caperatic (7), lobaric (8), and protolichesterinic (9) acids. All acetone extracts were evaluated for their 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability and subjected to Artemia salina bioassay. The free-radical-scavenging activities of each extract (100 mu g) ranged from 8.9 +/- 0.1% to 38.7 +/- 2.5% and the EC50 values ranged from 0.24 +/- 2.10 to 3.54 +/- 0.28 mg mL(-1), while the toxicity of the extracts against A. salina were low (151.0 to >600 mu g mL(-1)).