Efeito do extrato aquoso das folhas de eugenia punicifolia (khunt) dc em modelos experimentais relacionados à síndrome metabólica denise

Abstract

Galeno D.M.L. Effects of Eugenia punicifolia (Khunt ) DC related to metabolic syndrome in experimental models . Manaus, 2014. 133p. Thesis (Ph.D.) - Graduate Program Multi - Institutional Biotechnology, Federal University of Amazonas. The Eugenia punicifolia species is a plant popularly known as "pedra-ume-caa", widely distributed in the Amazon region. In the state of Amazonas, this species has been widely used in folk medicine to treat inflammatory and hyperglycemic disorders. However, studies involving other parameters found in the metabolic syndrome (MS) have not yet been elucidated. The MS is characterized by a complex disorder, represented by a number of cardiovascular risk factors involving central adiposity, hypertension, endothelial dysfunction and insulin resistance. Studies have shown that nutritional supplementation with plants that effectively address the pathogenic mechanisms of this syndrome represents an effective improvement for the problem. This project aim was to analyze biological activities in vitro and in vivo of the aqueous extract of the leaves of E. punicifolia (EEP), emphasizing the inhibitory activity digestive enzymes, angiotensin converting enzyme (ACE) inhibitor, antioxidants, hypolipemiant, cytotoxic and anti antihypertensive effects. Enzyme inhibition assays, as well as the determination of the ACE activity in Wistars rats serum were performed by the fluorometric method and the indirect tests of cell viability, antioxidants, determining the presence of flavonoids and phenolic compounds were performed by colorimetric assays. The evaluation of the EEP on blood pressure parameters was performed by using five experimental groups, which were randomly divided into: normotensive group (2R), the hypertensive group (2R1C), enalapril hypertensive group (ENAL), extract hypertensive group 150 mg/kg/day (EEP150) and extract hypertensive group 300 mg/kg/dia (EEP300). The effects of EEP in systolic pressure were acquired indirectly by tail plethysmography in conscious rats. Biochemical parameters were measured in rat’s plasma through appropriate kits. The study has shown, for the first time, that EEP exhibited scavenging activity on ABTS·+, DPPH·, and O2·- (IC50=10.5 ± 1.2; 28.84 ± 0.54 and 38.12 ± 2.6 μg/mL, respectively). The EEP also exhibited cellular antioxidant activity in vitro concentration-dependent manner, and did not show cell cytotoxic effects. Furthermore, the EEP inhibited ACE activity (70.8%) using the concentration of 0.3 mg/mL (IC50 of 24.3 ± 0.7 mg/mL), and inhibited the activities of the enzymes α-amylase (IC50 = 122.8 ± 6.3 mg/mL), α-glucosidase (IC50 = 2.9 ± 0.1 mg/mL) and xanthine oxidase (IC50 = 23.5 ± 2.6 mg/mL). Both the EEP150 (21.7%) and the EEP300 (16.8%) reduced systolic blood pressure. The hypotensive effect of EEP correlated with the reduction of plasma ACE activity and also reduced total cholesterol (48%), triglycerides (52%), VLDL (52%) and LDL (55%). In addition, the EEP wasn’t cause renal, hepatic or neurotoxic acute or chronic toxicity. The EEP showed antioxidants, hypotensive, hypolipidemic effects and digestive enzymes and ACE were inhibited. These activities are probably related to the presence of antioxidant such as phenols and flavonoids compounds present in the extract, which act by inhibiting key enzymes of carbohydrate metabolism and angiotensin converting enzyme. These findings may support further clinical studies to further evaluate the potential of EEP on the SM.