Composição química, atividade antioxidante e toxicológica de Chaptalia nutans (L.) Polack

Abstract

Chaptalia nutans is a species widely used in popular medicine in southern Brazil as laxatives, antitussive, and especially in topical preparations for trauma, wounds and hemorrhages. The objective was to evaluate the chemical constitution of the methanolic extract of the leaves and roots of C. nutans, as well as to verify the antioxidant activity in different methods, antimicrobial and the toxicity of the extracts using different models. To elucidate the compounds present in the extract, a phytochemical screening was performed, as well as High Performance Liquid Chromatography, coupled to Diodes Detector and Mass Spectrometry (HPLC-DAD-MS). The antimicrobial activity of the crude extracts and fractions was individually evaluated against bacteria and fungus by the broth microdilution test. The antioxidant capacity was verified by the radical 2,2-diphenyl-1-picrilhidrazil (DPPH), iron reduction capacity (FRAP), substances reactive to thiobarbituric acid (TBARS), carbonyl rotein and dichloro-dihydro-fluorescein diacetate (DCFH-DA). As a preliminary toxicity test, the Artemia salina bioassay was used. After that, the cytotoxicity and genotoxicity of the extract was evaluated using the Allium cepa test system and, finally, a more complex experimental model, Drosophila melanogaster, was used to evaluate neurotoxic compounds. The presence of a large number of active phytochemicals, such as alkaloids, coumarins, flavonoids, terpenes and mainly phenolic compounds, may justify the antioxidant capacity of the extracts, which in concentrations of 0.1, 1 and 10 mg/mL demonstrated the potential to protect the cells from lipid and protein damage, as well as the neutralization of peroxy radicals. Leaf extract at a concentration of 1000 μg/mL and root extract at the three tested concentrations 10, 100 and 1000 μg/mL proved to be extremely promising in decreasing malondialdehyde (MDA) levels. The crude extract of the leaves of C. nutans was not effective against the tested microorganisms, only the hexane fraction, at a concentration of 1000μg/mL, significantly inhibited the microorganisms: Staphylococcus epidermidis, Candida tropicalis, Candinda glabrata and Candida krusei and the chloroform fraction of the root at a concentration of 500μg / mL, inhibited only Eschechiria coli. Regarding to the toxicity of the extracts, C. nutans was not toxic at the concentrations tested in the different models in vivo, with no cytotoxicity, genotoxicity and neurotoxicity. The roots, in the A. cepa model, in the highest concentration showed a 50% protection capacity against chromosomal abnormalities caused by glyphosate, as well as 80% protection, in the D. melanogaster test in the three tested concentrations, from the locomotor deficit caused by Paraquat®. The leaves and roots of C. nutans showed promising results, leading the way for the possible development of natural antioxidants after more specific investigations, elucidating the mechanisms of action of the extracts and elucidating the reduction of dysfunctional factors involved in the neurodegeneration process.