ABSTRACT Leaves of Psidium guajava L. (guava) have been widely used in the popular way for prevention and treatment of various diseases. Thus, the objective of this study was to evaluate the inhibitory potential of leaves aqueous extract from three cultivars of P. guajava (Pedro Sato, Paluma and Século XXI) on α-amylase, α-glycosidase, lipase, and trypsin enzymes, in the presence or not of simulated gastric fluid and to determine the content of phenolic compounds by high performance liquid chromatography. All cultivars presented the same composition in phenolic compounds, but in different proportions. The compounds identified are gallic acid, epigallocatechin gallate, syringic acid, o-coumaric acid, resveratrol, quercetin, and catechin (which was the major compound in all the cultivars evaluated). In the absence of simulated gastric fluid, it was observed different inhibitions exercised by the leaves aqueous extracts from three cultivars of P. guajava on each enzyme. In presence of simulated gastric fluid, all cultivars showed increase in the inhibition of lipase and α-glycosidase, and decrease in inhibition of α-amylase and trypsin enzymes. These results indicate that P. guajava leaves aqueous extracts from all cultivars evaluated possess potential of use as an adjuvant in the treatment of obesity and other dyslipidemias.

ABSTRACT Adding value to fruit residues is of great interest, since they can be presented as a viable solution in search of new drugs for the treatment of obesity and related diseases, due to bioactive substances, especially phenolic compounds. Thus, the objective of this study was to prepare the methanol extract of acerola bagasse flour, in order to evaluate its potential as a source of inhibitors of the enzymes α-amylase, α-glucosidase, lipase and trypsin, and determine the content of phenolic compounds by high performance liquid chromatography. Enzymatic inhibition assays were conducted in the presence or absence of simulated gastric fluid. In the methanol extract of acerola bagasse flour, the following phenolic compounds were identified: gallic acid, syringic and p-coumaric acid, catechin, epigallocatechin gallate, epicatechin and quercetin; epicatechin was the major compound. In the absence of gastric fluid, simulated enzymes had a variable inhibition of the acerola bagasse flour extract, except for lipase, which was not inhibited. In the presence of simulated gastric fluid, there was an inhibition of 170.08 IEU (Inhibited Enzyme Unit in µmol min−1 g−1) for α-amylase and 69.29 IEU for α-glucosidase, indicating that this extract shows potential as an adjuvant in the treatment of obesity and other dyslipidemia.

RESUMO A inibição enzimática por compostos naturais e/ou de baixo custo pode representar um valioso adjuvante ao tratamento soroterápico tradicional realizado em casos de ofidismo, com vistas a amenizar principalmente os efeitos locais do envenenamento. Objetivou-se avaliar in vitro possíveis interações entre vitaminas e enzimas presentes nas peçonhas de Bothrops atrox e Crotalus durissus terrificus. Ensaios de inibição de proteólise (substratos: azocaseína, colágeno, gelatina e fibrinogênio), hemólise, coagulação, hemaglutinação, foram realizados utilizando diferentes proporções de vitaminas em face de inibir à dose mínima efetiva de cada peçonha. As vitaminas foram responsáveis por reduzir 100% a quebra da azocaseína por peçonha de C.d.t., a trombólise induzida por B. atrox e a fibrinogenólise induzida por ambas as peçonhas. Sugere-se a presença de interações de vitaminas com o sítio ativo das enzimas, como por exemplo, interações entre regiões hidrofóbicas presentes nas enzimas e vitamina E, assim como, inibição de algumas atividades por mecanismo de ação antioxidante.

ABSTRACT The enzyme inhibition by natural and/ or low-cost compounds may represent a valuable adjunct to traditional serotherapy performed in cases of snakebite, mainly with a view to mitigate the local effects of envenoming. The objective of this study was to evaluate possible interactions between vitamins and enzymes that comprise Bothrops atrox and Crotalus durissus terrificus venoms, in vitro. Proteolysis inhibition assays (substrates: azocasein, collagen, gelatin and fibrinogen), hemolysis, coagulation, hemagglutination were carried out using different proportions of vitamins in face of to inhibit minimum effective dose of each venom. The vitamins were responsible for reducing 100% of breaking azocasein by C.d.t. venom, thrombolysis induced by B. atrox and fibrinogenolysis induced by both venoms. It is suggested the presence of interactions between vitamin and the active site of enzymes, for example the interactions between hydrophobic regions present in the enzymes and vitamin E, as well as the inhibitions exercised by antioxidant mechanism.