Identificação por espectrometria de massas de fontes botânicas em amostras comerciais de miraruíra e avaliação do seu potencial antioxidante

Abstract

Miraruíra or cipó-miraruíra is a medicinal liana used in the Amazon region for the treatment of various diseases, including diabetes. However, its botanical nature is imprecise, as at least two plant species, Salacia impressifolia and Connarus ruber, have this popular name. Therefore, the present study aimed to identify the botanical nature of the miraruíra marketed in the state of Amazonas through the analysis of the chemical profile of commercial miraruíra and authentic samples of S. impressifolia and C. ruber, in addition to investigating their antioxidant potential. Initially, ten commercial samples (A-J) were purchased in markets, fairs and emporiums distributed throughout the city of Manaus-AM, and, along with authentic samples of S. impressifolia and C. ruber, had their aqueous extracts prepared by decoction. Then, all the aqueous extracts were subjected to a clean-up procedure using the solid phase extraction (SPE) technique, and the resulting methanolic fractions were analyzed by mass spectrometry (MS). Finally, the chemical profiles obtained were submitted to PCA and HCA analyses. On the other hand, the total phenolic content (TPC) of the aqueous extracts was evaluated, as well as their antioxidant potential through DPPH and FRAP assays. The clean-up procedure of the aqueous extracts removed interferences to MS analysis, such as fructose or glucose and sucrose, ensuring a satisfactory analysis of the chemical profile of the investigated samples. The MS analysis revealed distinct chemical profiles for the S. impressifolia and C. ruber samples, and pointed out characteristic chemical markers for each sample: mangiferin for S. impressifolia and epicatechin for C. ruber. Moreover, based on PCA analysis, all commercial samples of miraruira showed chemical profiles similar to the species C. ruber, suggesting that the species C. ruber is marketed as miraruira in the state of Amazonas. In turn, the HCA analysis showed chemical variability among commercial samples, which may indicate that other species of the Connarus genus, such as C. perrottetii, or even species of other genera of the Connaraceae family, such as R. cuspidata, may be used as miraruira. On the other hand, the TPC of C. ruber (46.52 mg GAE/g) was higher than that observed for S. impressifolia (8.91 mg GAE/g). In addition, C. ruber also showed the highest antioxidant potential based on the DPPH (CS50 = 171.36 μg/ml) and FRAP (266.52 μmol Fe (II)/g) assays, which suggests that products based on C. ruber have greater antioxidant capacity than those based on S. impressifolia, and therefore should bring greater therapeutic benefit for the treatment of diseases related to the oxidative process, such as diabetes.