Perfil fitoquímico, atividade antioxidante e citogenotóxica de Jatropha mollissima (POHL) BAILL.

Abstract

The diversity of the national flora is a source of a considerable variety of phytochemical components with diverse bioactivity. In Brazil, the therapeutic benefits of medicinal plants have been recorded since the colonial period. The use of this secular knowledge is based on popular empiricism, linked to oral transmission between generations, contributing positively to the dissemination of the healing effects of plants. Therefore, the leaves, stem and roots are popularly known sources of substances with therapeutic potential. As an example, we can mention the species Jatropha mollissima (Euphorbiaceae), known in northeastern Brazil as pinhão-bravo or pinhão-de-purga, used in popular medicine as anti-inflammatory, anti-ophidian and antimicrobial. Therefore, this work aims to identify the main classes of secondary metabolites and evaluate the antioxidant and cytogenotoxic activities of the Hexane (HE), Ethyl Acetate (AE) and Methanolic (ME) fractions of the ethanolic extract of J. mollissima leaves. After producing the crude leaf extract, carried out by exhaustive cold extraction in absolute ethanol for 72 hours, the extract was partitioned according to the increasing polarities of the solvents used, in order to obtain the fractions: HE, AE and ME . The antioxidant activities of the fractions were determined by scavenging and eliminating the DPPH• radical and by the ABTS•+ assay. The Folin-Ciocalteu method was used to analyze the total phenol content and the cytogenotoxic effect was evaluated by the Allium cepa bioassay. Onion seeds were germinated in a Petri dish, after reaching 2 cm they were transferred to different concentrations (0.01; 0.1; 1 and 10 mg/mL) of the fractions under study. Methyl-Methane-Sulfonate 10 mg/L (MMS) was used as a positive control and DMSO 1% as a negative control. After 24h of exposure, the roots were fixed in Carnoy. Cytogenotoxicity was assessed by counting, under a light microscope (400 x), 5,000 meristematic cells (500 cells/slide). Phytochemical analyzes revealed the presence of triterpenes in HE, which were also observed together with flavonoids in AE. Saponins, catechins, phenols, tannins, flavonoids, flavones, flavonols and xanthones were found in ME. The total phenolic content showed that the fractions have phenolic compounds in different quantities, where ME and HE have, respectively, the highest and lowest values. The increasing order of antioxidant activity coincides with the molecular polarity of the solvents used to obtain the researched fractions. HE, AE and ME are in the order of effectiveness found in reducing DPPH• and ABTS•+ radicals. The tested dilutions, except for the two lowest ME, demonstrated significant cytotoxic potential, while mutagenic and genotoxic effects were observed only at the two highest ME concentrations.