title: Neuroprotective activity and cytotoxic potential of two Parmeliaceae lichens: Identification of active compounds.
abstract: BACKGROUND
  Lichens are symbiotic organisms capable of producing unique secondary metabolites, whose pharmacological activities are attracting much interest.
  
  
  OBJECTIVE
  The present study aimed to investigate the in vitro neuroprotective effects and anticancer potential of methanol extracts of two Parmeliaceae lichens: Cetraria islandica and Vulpicida canadensis. The chemical composition of the two lichens was also determined.
  
  
  METHODS
  Neuroprotective activity was studied with respect to the antioxidant properties of the extracts; radical scavenging tests (ORAC and DPPH assays) were performed and oxidative stress markers (intracellular ROS production, caspase-3 activity, MDA and glutathione levels) were assessed in a hydrogen peroxide-induced oxidative stress model in astrocytes. Cytotoxic activity was tested against human HepG2 (hepatocellular carcinoma) and MCF-7 (breast adenocarcinoma) cell lines.
  
  
  RESULTS
  Cell viability studies identified a single concentration for each extract that was subsequently used to measure oxidative stress markers. Lichen extracts were able to reverse the oxidative damage caused by hydrogen peroxide, thus promoting astrocyte survival. Both lichen extracts also had anticancer activity in the cell lines, with IC50 values of 19.51-181.05 µg/ml. The extracts had a high total phenolic content, and the main constituents identified by HPLC were fumarprotocetraric acid in Cetraria islandica, and usnic, pinastric and vulpinic acids in Vulpicida canadensis. The biological activities of the lichen extracts can be attributed to these secondary metabolites.
  
  
  CONCLUSIONS
  The lichen species studied are promising sources of natural compounds with neuroprotective activity and cytotoxic potential, and warrant further research.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, University Complutense of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Fernández-Moriano
authors.affiliation: Department of Plant Biology II, Faculty of Pharmacy, University Complutense of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Divakar
authors.affiliation: Department of Plant Biology II, Faculty of Pharmacy, University Complutense of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Crespo
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, University Complutense of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain. Electronic address: pserra@ucm.es.
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Gómez-Serranillos
mesh_terms: D001253:Astrocytes / Q000187:drug effects; D001688:Biological Products / Q000737:chemistry; D053148:Caspase 3 / Q000378:metabolism; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005978:Glutathione / Q000737:chemistry; D056945:Hep G2 Cells; D006801:Humans; D006861:Hydrogen Peroxide; D020128:Inhibitory Concentration 50; D008011:Lichens / Q000737:chemistry*; D015227:Lipid Peroxidation; D061986:MCF-7 Cells; D015394:Molecular Structure; D018696:Neuroprotective Agents / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects*; D010636:Phenols / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000737:chemistry
chemical_list: D001688:Biological Products; D016166:Free Radical Scavengers; D018696:Neuroprotective Agents; D010636:Phenols; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; C505407:CASP3 protein, human; D053148:Caspase 3; D005978:Glutathione
keywords: Cytotoxic potential; HPLC; Lichens; Neuroprotective activity; Parmeliaceae; Phytochemical analysis