Analysis of antioxidants mechanisms in the antiulcerogenic activity of Anacardium humile St. Hil. (Anacardiaceae)

Author(s)

Ana Cristina Alves de Almeida

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2010-02-18

Examining board members

Alba Regina Monteiro Souza Brito; Clélia Akiko Hiruma Lima; Marcos José Salvador

• Advisor: Alba Regina Monteiro Souza Brito

Abstract

Anacardium humile, popularly known as "cajuzinho-do-cerrado", is used in traditional medicine for the treatment of various inflammatory diseases. Extracts and fractions of leaves of A. humile present phenolic compounds and significant antiulcer activity. In this study, we evaluated the possible antioxidant mechanisms in the antiulcerogenic activity conferred by the ethyl acetate fraction of leaves of A. humile (AHFAc). AHFAc is rich in phenolic compounds; there are more than 30% of soluble phenolic compounds in this fraction, according to results from the Folin Ciocalteu assay. AHFAc shows antioxidant activity in the 1, 1-diphenyl-1-picryl picrylhydrazyl (DPPH) assay, which represents a potential free radical scavenging action. There have been recorded the chromatographic profile AHFAc in high performance liquid chromatography and the mass spectrum by electrospray ionization mass spectrometry, which indicate the presence of gallic acid and derivatives, quercetin, kaempferol and amentoflavone (biflavonoid).The pharmacological activity of AHFAc was examined in ischemia and reperfusion induced and absolute ethanol-induced gastric ulcer models. Unib: WH rats were treated with the vehicle Tween 80 12% (10 ml.kg-1) or AHFAc (25, 50 and 100 mg.kg-1) and underwent ischemia (30 minutes) and reperfusion (60 minutes) of stomach or the administration of 1 ml of absolute ethanol. SHAM group was formed by untreated animals exposed to experimental procedures, but without effective induction of ulcer. After experimental models, the stomach of the animals was removed, the ulcerative lesion area (ULA) determined, a portion of the stomach was fixed for histological analysis (hematoxylin-eosin staining and periodic acid Schiff staining) and immunohistochemistry analysis (myeloperoxidase and superoxide dismutase), the remaining portion of the glandular stomach was scraped and homogenized for biochemical assays. We measured the levels of sulfhydryl groups (G-SH), DNA fragmentation, activity of myeloperoxidase (MPO), glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD) enzymes. The pre-treatment with AHFAc (50 mg.kg-1) showed gastroprotective effect in both experimental models of gastric ulcer, while maintaining the integrity of the mucosa and a tendency for increased levels of mucus. The administration of AHFAc was also effective in maintaining normal levels of G-SH and fragmentation of DNA, SOD and GPx activities in the gastric mucosa exposed to the harmful effect of absolute ethanol. In addition, AHFAc prevented the increase of MPO activity in gastric mucosa of rats subjected to the experimental models investigated, indicating less infiltration of neutrophils in the stomach of animals treated with the fraction. The anti-ulcer action of AHFAc must involve antioxidant activity, due to its phenolic composition, combined with other mechanisms of action. Since there was no modulation in the activity of antioxidant enzymes, and for presenting reduction capacity of DPPH, the antioxidant activity of AHFAc probably involves scavenger activity of free radicals. (AU)

• FAPESP's process: 07/53362-6 - Mechanisms of action involved in antiulcerogenic activity of Anacardium humile St. Hil. (Anacardiaceae)
• Grantee: Ana Cristina Alves de Almeida
• Support Opportunities: Scholarships in Brazil - Master