Fitoterápicos a base de Uncaria tomentosa e Uncaria guianensis: prospecção de inibidores enzimáticos

Abstract

Herbal medicines are drugs made from medicinal plants or their derivatives, which are a viable and effective alternative therapy. Inflammatory diseases have increasingly affected the world population, highlighting the need for development and application of alternative or adjuvant treatments. Based on popular knowledge and scientific information, species of the genus Uncaria possess pharmacological properties. The species Uncaria tomentosa and Uncaria guianensis, popularly known as cat's claw, are medicinal plants rich in bioactive compounds with anti-inflammatory properties, and are widely used for the treatment of joint and muscle pain. Thus, the aim of this study was to characterize the phenolic compounds by high performance liquid chromatography (HPLC) and to evaluate the in vitro effects of aqueous extracts of U. tomentosa and U. guianensis on phospholipases A2 and proteases (involved in hemostasis and inflammation), using Bothrops moojeni venom as a laboratory tool. The aqueous extract of U. guianensis showed higher content of phenolic compounds detected by HPLC when compared to the extract of U. tomentosa. The phospholipase activity induced by B. moojeni venom was significantly inhibited by both extracts, ranging from 10 to 18% and 10 to 46% for U. tomentosa and U. guianensis aqueous extracts, respectively. The greatest inhibitory action on hemolysis was observed for the aqueous extract of U. guianensis when incubated with B. moojeni venom, with results ranging from 14 to 60%. In the thermal hemolysis assay, the higher doses tested exerted a greater protective effect on erythrocyte membranes. The proteolytic activity was significantly inhibited from 10 to 27% for the aqueous extract of U. tomentosa and from 10 to 40% for U. guianensis. For the thrombolytic activity significant inhibition was observed only in the highest dose of aqueous extract of U. guianensis (53%) and the controls containing only the extracts showed thrombolytic action. Both extracts were able to prolong the coagulation time, induced by B. moojeni venom. The results show that the aqueous extracts of herbal medicines based on U. tomentosa and U. guianensis showed modulating action on phospholipases A2 and proteases, characterizing these herbal medicines as promising alternatives for the treatment of diseases related to disorders in hemostasis and inflammatory processes. However, further studies are needed to expand the characterization of these extracts and elucidate mechanisms of interaction of bioactive compounds present in phytotherapeutics based on cat's claw, aiming the prospection of new indications of therapeutic use to human health.