Prospecção química e de atividades antioxidante e antiproliferativa dos extratos de Myrciaria tenella (DC.) O. Berg (Myrtaceae) e Salvia hispanica L. (Lamiaceae)

Abstract

Considering the importance of plants as a source of biomolecules with medicinal action, the objective of this work was to evaluate the antioxidant and antiproliferative activity of cambuí (Myrciaria tenella (DC.) O.Berg) and chia (Salvia hispanica L.) extracts. It was obtained extract using fresh leaves and a serial extraction approach using apolar to polar solvent. Then, it was obtain the following extracts: hexane extract (EHC and EHSh); chloroform (ECC and ECSh); ethanolic (EEC and EESh); methanolic (EMC and EMSh) and final aqueous (EAFC and EAFSh). Furthermore, it was also made an aqueous extract (EAC and EASh). These extracts were phytochemically characterized by measuring sugar, protein and total phenol. It was also analyzed by TLC and UHPLC. The antioxidant activity was measured using different in vitro assays (CAT, reducing power, iron and copper chelation, hydroxyl, superoxide and DPPH) and in vivo assays (ROS, SOD-3 expression and survival under stress conditions). Moreover, the toxicity from these extract were also analyzed using cell culture and the Caenorhabditis elegans model. In relation to cell lines it was measured the MTT reduction on murine fibroblasts (3T3), the human cervical cancer cells (HeLa) and the gastric adenocarcinoma (AGS). The tumour cell lines were also analyzed by flow citometry. The Caenorhabditis elegans model was evaluating the egg hatching rates and animal size. The results obtained here showed that the M. tenella polar extracts (EEC, EMC, EAFC) had phenolic compounds and it was identified the presence of rutin in EEC and probably at EMC. In M. tenella nonpolar extracts (EHC and ECC) it was identified the presence of terpenes as ursolic acid. The in vitro antioxidant assays showed that these extracts were able to scavening ROS and chelate metals. Furthermore, in vivo antioxidante assays using C. elegans model showed that EEC was able to reduced ROS content by up to 74% when compared to untreated control. For cell lines, it was observed that M. tenella extracts did not change the MTT reduction, on the other hand it was observed a reduction on cell viability up to 82.61% and 84.68% for HeLa and AGS, respectively. Flow cytometry data showed that the cell viability reduction for AGS was correlated to necrosis (80.7%) and late apoptosis (16.5%). The data obtained for chia (S. hispanica) showed a similar phytochemical profile, the terpenes presence in EHSh and ECSh and the presence of ursolic acid. The presence of phenolic compounds in all extracts was verified by UHPLC. In addition, it was observed that these extracts were able to donate electrons to the oxidized substrate and to chelate metals as iron and copper. In vivo assays showed that the C. elegans pre-treatment with EASh reduced the ROS levels to 29.76%. Thus, it was observed that S. hispanica extracts were able to reduce the cell viability from HeLa and AGS cell lines by up to 82.62% and 66.5% and for HeLa it was related to necrosis (19.6%), on the other hand for the AGS was associated to initial apopthosis (8.09%) and to late apoptosis (7.16%). Then, M. tenella and S. hispanica leaves may be considered as a potential source of biomolecules with antioxidant and antiproliferative activity.