Avaliação fitoquímica, microbiológica e citotóxica da cavalinha (Equisetum arvense)

Abstract

Medicinal plants have been used in popular medicine for centuries, a practice that has been practiced between generations. They are rich in active substances, which can lead to the discovery of a new herbal remedy and even the discovery of a new drug. The Equisetum arvense, popularly known as horsetail and present in RENISUS is a plant rich in silicon and also consisting of polyphenols and tannins, being used in therapy as diuretic, but also has a healing, antioxidant, anti-inflammatory and antimicrobial action. Considering the current panorama of microbial resistance, studies that are proposed to evaluate antimicrobial activity, as well as cytotoxic, are of great relevance. The objective of the present work is to evaluate the phytochemical profile, antimicrobial activity and the cytotoxicity of the extract and fractions of E. arvense. The gross extract was obtained by maceration of the horsetail in ethanol, while the fractions were by maceration of the horsetail in solvents of different polarities (hexane, chloroform, ethyl acetate and methanol), and then concentrated in a rotary evaporator. The phenolic profile was composed by the phenol content by Folin-Ciocalteu, total flavonoids and identification of phenolic substances by HPLC with UV-DAD detector; the antioxidant activity was verified by DPPH; the evaluation of the antimicrobial activity was verified by the disc diffusion method using ATCC strains of S. aureus, E. coli and P. aeruginosa; and, cytotoxicity was performed on J774 lineage macrophages and determined by the Elisa assay at 530 nm using MTT as the cell death indicator. The results obtained showed the presence of phenolic compounds in the horsetail, such as phenolic acids and flavonoids, resulting in a good content of phenols and flavonoids in its extract and fractions and also in a high antioxidant activity, being this greater than 90% for the ethyl acetatel fraction. In relation to the antimicrobial activity, the ethyl acetate fraction was able to inhibit the growth of S. aureus and P. aeruginosa, while the chloroform fraction was able to inhibit the growth of E. coli as well, being this concentration dependent inhibition of the fraction. As for cytotoxicity, the hexane and methanol fractions of the plant presented LC50 of 67,66 and 74,33 μg/mL, respectively, these fractions being the most cytotoxic for J774 lineage macrophages, whereas gross ethanolic extract and fractions chloroform and ethyl acetate showed LC50 greater than 100 μg/mL. Therefore, the ethyl acetate fraction was highlighted, being the fraction with higher content of phenols and flavonoids, resulting in a high antioxidant activity, besides being able to inhibit the growth of S. aureus and P. aeruginosa when used in concentration of 500 mg / mL, and did not present significant cytotoxicity, without significantly damaging the cells. It is emphasized, then, that the horsetail has bioactivity with pharmacological function depending on its concentration, however it is a plant and due to the great diversity of its constituents may also exhibit certain toxicity.