Four Brazilian Potential Species Almost Unexplored of Connaraceae Family Used Popularly for Diabetes: Chemical Composition and in vitro Activity

Abstract

Connaraceae is a plant family usually used in traditional medicine. Recently, we have reported the chemical composition and biological activity of 39 species around the world. This work highlights the application of these species to diabetes control, which has been reported at least to half of this family. In this line, there are several species of the Connaraceae without scientific evidence of traditional use, among these the four species study here. Thus, this work aims the chemical composition prospection of Connarus blanchetii, Connarus regnellii, Connarus suberosus and Rourea glazioui, as well as the identification of possible bioactivity. The leaves of these four species were collected, prepared and submitted to different extractive methods (aqueous decoction and infusion and ethanolic maceration), these being tested in a preliminary phytochemical investigation and subjected to antioxidant assay with 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power. Then, we selected the maceration extract to continue for fractions, with the ethyl acetate and n-butanol presenting the best results with antioxidant and anti-advanced glycation end products (AGEs) activity potential. Finally, the chemical composition was determinate by high-resolution mass spectrometry (HRMS) in combination with Global Natural Products Service (GNPS) data bank. As a result, this study indicated the presence of 29 phenolics compounds with reported activity as antioxidant and with potential of protein glycation, supported the diabetes activity of this plants. The n-butanolic fraction of R. glazioui showed compounds such as apigenin, kaempferol, quercetin, myricetin and chlorogenic acid, which have generated a half maximal inhibitory concentration (IC50) of 36.5 µg mL-1 for oxidative glycation inhibition, being highlighted as the most active.