Introduction The generation of reactive oxygen species (ROS) is commonly related to gastric lesions caused by stress, alcohol consump- tion, Helicobacter pylori infection and due to the use of non- steroidal anti-inflammatory drugs [1]. It is widely accepted that some free radical scavengers show a protective effect against the mucosal damage induced by free radicals [2], [3]. Examination of the phytochemical data regarding antiulcer molecules reveals that several types of compounds, including terpenes, flavonoids and alkaloids, present antioxidant proper- ties [4]. Antioxidant Activity of Indigo and its Preventive Effect against Ethanol-Induced DNA Damage in Rat Gastric Mucosa Elisangela Farias-Silva 1 Maíra Cola 1 Tamara R. Calvo 2 Victor Barbastefano 1 Anderson L. Ferreira 1 Debora De Paula Michelatto 1 Ana Cristina Alves de Almeida 1 ClØlia A. Hiruma-Lima 3 Wagner Vilegas 2 Alba R. M. Souza Brito 1 Affiliation 1 Departamento de Fisiologia e Biofísica, IB, UNICAMP, Campinas - SP, Brasil 2 Departamento de Química Orgânica, IQ, UNESP, Araraquara - SP, Brasil 3 Departamento de Fisiologia, IBB, UNESP, Botucatu - SP, Brasil Correspondence Prof. Dr. Alba Regina Monteiro Souza Brito ´ Departamento de Fisiologia e Biofísica ´ IB ± UNICAMP ´ Cidade Universitµria ªZeferino Vazº ´ Baro Geraldo ´ Campinas - SP ´ Brasil 13083±970 ´ Phone: +55-19-3521-6188 ´ Fax: +55-19-3521-6284 ´ E-mail: abrito@unicamp.br Received January 18, 2007 ´ Revised July23,2007´ Accepted July 23, 2007 Bibliography Planta Med 2007; 73: 1241±1246  Georg Thieme Verlag KG Stuttgart ´ New York DOI 10.1055/s-2007-981613 ´ Published online September 20, 2007 ISSN 0032-0943 Abstract Ethanol-induced oxidative damage is commonly associated with thegenerationofreactiveoxygenmolecules,leadingtooxidative stress. Considering that antioxidant activity is an important mechanism of action involved in cytoprotection, the aim of this work was to evaluate the antioxidant properties of the alkaloid indigo (1) (2mg/kg, p. o.), obtained from the leaves of Indigofera truxillensis Kunth (Fabaceae), on rat gastric mucosa submitted to ethanol-induced (100%, 1 mL, p. o.) gastric ulcer. Enzymatic as- says and DNA fragmentation analysis were performed. When ethanol was administered to the control group, the sulfhydryl content (SH) and the glutathione peroxidase (GPx) activity de- creased by 41% and 50%, respectively; in contrast, superoxide dismutase (SOD) and glutathione reductase (GR) activities in- creased by 56% and 67%, respectively. Additionally, myeloperox- idase (MPO) activity, a marker for free radical generation caused by polymorphonuclear neutrophil (PMN) tissue infiltration, also increased 4.5-fold after ethanol treatment. Rat gastric mucosa exposed to ethanol showed DNA fragmentation. Indigo alkaloid pretreatment protected rats from ethanol-induced gastric le- sions. This effect was determined by the ulcerative lesion area (ULA),indicatinganinhibitionofaround80%at2mg/kg.Thisal- kaloid also diminished GPx activity, which was higher than that observed with ethanol alone. However, this effect was counter- balanced by increased GR activity. Indigo was unable to restore alterations in SOD activity promoted by ethanol. After indigo pretreatment, SH levels and MPO activity remained normal and gastricmucosaDNAdamagecausedbyethanolwasalsopartially prevented by indigo. These results suggest that the gastroprotec- tive mechanisms of indigo include non-enzymatic antioxidant effects and the inhibition of PMN infiltration which, in combina- tion, partially protect the gastric mucosa against ethanol-in- duced DNA damage. Key words Alkaloids ´ Indigofera truxillensis ´ indigo ´ Fabaceae ´ free radicals ´ antioxidant enzymes ´ gastric ulcer ´ MPO activity ´ DNA damage Supporting information available online at http://www.thieme-connect.de/ejournals/toc/plantamedica Original Paper 1241 Downloaded by: Dot. Lib Information. Copyrighted material.