title: Antioxidant activity and mechanisms of action of natural compounds isolated from lichens: a systematic review.
abstract: Chronic diseases such as cancer, diabetes, neurodegenerative and cardiovascular diseases are characterized by an enhanced state of oxidative stress, which may result from the overproduction of reactive species and/or a decrease in antioxidant defenses. The search for new chemical entities with antioxidant profile is still thus an emerging field on ongoing interest. Due to the lack of reviews concerning the antioxidant activity of lichen-derived natural compounds, we performed a review of the antioxidant potential and mechanisms of action of natural compounds isolated from lichens. The search terms "lichens", "antioxidants" and "antioxidant response elements" were used to retrieve articles in LILACS, PubMed and Web of Science published until February 2014. From a total of 319 articles surveyed, 32 met the established inclusion and exclusion criteria. It was observed that the most common isolated compound studied was usnic acid, cited in 14 out of the 32 articles. The most often described antioxidant assays for the study of in vitro antioxidant activity were mainly DPPH, LPO and SOD. The most suggested mechanisms of action were scavenging of reactive species, enzymatic activation and inhibition of iNOS. Thus, compounds isolated from lichens are possible candidates for the management of oxidative stress, and may be useful in the treatment of chronic diseases.
authors.affiliation: Department of Physiology, Federal University of Sergipe, São Cristóvão, Sergipe 49100-000, Brazil. pollyannawhite@gmail.com.
authors.forename: Pollyanna A S
authors.initials: PA
authors.lastname: White
authors.affiliation: Medicinal Plants Research Center, Federal University of Piauí, Teresina, Piauí 64049-550, Brazil. aldeidia@gmail.com.
authors.forename: Rita C M
authors.initials: RC
authors.lastname: Oliveira
authors.affiliation: Medicinal Plants Research Center, Federal University of Piauí, Teresina, Piauí 64049-550, Brazil. aldeidia@gmail.com.
authors.forename: Aldeidia P
authors.initials: AP
authors.lastname: Oliveira
authors.affiliation: Nucleus of Pharmacy, Federal University of Sergipe, Lagarto, Sergipe 49100-000, Brazil. maiserafini@hotmail.com.
authors.forename: Mairim R
authors.initials: MR
authors.lastname: Serafini
authors.affiliation: Department of Pharmacy, Federal University of Sergipe, São Cristóvão, Sergipe 49100-000, Brazil. adriasa2001@yahoo.com.br.
authors.forename: Adriano A S
authors.initials: AA
authors.lastname: Araújo
authors.affiliation: Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90035-003, Brazil. dgelain@yahoo.com.br.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Gelain
authors.affiliation: Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90035-003, Brazil. jcfm@ufrgs.br.
authors.forename: Jose C F
authors.initials: JC
authors.lastname: Moreira
authors.affiliation: Center for Studies and Research of Medicinal Plants, Federal University of San Francisco Valley, Petrolina, Pernambuco 56304-205, Brazil. jackson.guedes@univasf.edu.br.
authors.forename: Jackson R G S
authors.initials: JR
authors.lastname: Almeida
authors.affiliation: Department of Physiology, Federal University of Sergipe, São Cristóvão, Sergipe 49100-000, Brazil. jullyanaquintans@gmail.com.
authors.forename: Jullyana S S
authors.initials: JS
authors.lastname: Quintans
authors.affiliation: Department of Physiology, Federal University of Sergipe, São Cristóvão, Sergipe 49100-000, Brazil.
authors.forename: Lucindo J
authors.initials: LJ
authors.lastname: Quintans-Junior
authors.affiliation: Department of Physiology, Federal University of Sergipe, São Cristóvão, Sergipe 49100-000, Brazil. marcio@infonet.com.br.
authors.forename: Marcio R V
authors.initials: MR
authors.lastname: Santos
mesh_terms: D061745:Antioxidant Response Elements; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D001572:Benzofurans / Q000378:metabolism; D001713:Biphenyl Compounds / Q000008:administration & dosage / Q000737:chemistry; D016166:Free Radical Scavengers / Q000378:metabolism; D006801:Humans; D008011:Lichens / Q000737:chemistry*; D009369:Neoplasms / Q000188:drug therapy*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010851:Picrates / Q000008:administration & dosage / Q000737:chemistry
chemical_list: D000975:Antioxidants; D001572:Benzofurans; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; C073339:usnic acid; C004931:1,1-diphenyl-2-picrylhydrazyl