Polygonum hydropiperoides Michx. (Polygonaceae Juss.): perfil metabolômico e potenciais antibacteriano e antibiofilme in vitro frente espécies de Salmonella

Abstract

Polygonum hydropiperoides Michx. (Polygonaceae Juss.), popularly known in Brazil as "erva-de-bicho", is an Asian native plant species also widely distributed in the Americas. Traditionally, it is used as an astringent, antidisenteric, anti-hemorrhagic, anti-hemorrhoids, diuretic, vermicide, against varicose veins, erysipelas, rheumatism and in the treatment of wounds. With this context in mind, the present study aimed to chemically characterize, deeply investigate the antibacterial potential and evaluate the antibiofilm potential, as well as to screening the in vitro toxicity of hexane (EH), ethyl acetate (EAE) and ethanolic (EE) extracts from aerial parts of P. hydropiperoides. The chemical characterization was performed through High Performance Liquid Chromatography with a Diode Array Detector and an ion trap Mass Spectrometer with an Electrospray Interface (HPLC-DAD-ESI/MSn ). The antibacterial potential was determined by the Minimal Inhibitory Concentration (MIC) using the broth microdilution method and the Minimal Bactericidal Concentration (MBC) followed by the classification of the antibacterial effect. For this purpose, five human clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) and five Salmonella spp. strains were tested, making a total of ten strains. In addition, the antibacterial potential was also be assessed through bacterial death kinetics and the effect of the extract combined with antibiotics used in clinical practice (combinatory effect) against Salmonella spp. strains. The antibiofilm potential against Salmonella spp. strains in polystyrene surface was evaluated. The acute in vitro toxicity screening was determined through the Artemia salina bioassay. Chemical characterization revealed the presence of phenolic acids and flavonoids in EAE. Regarding antibacterial activity, EAE proved to be the most effective extract among the tested, being active against all the ten strains with MIC values ranging from 625 to 2500 µg/mL and bacteriostatic effect. EAE also revealed the ability to interfere in the bacterial death kinetics, isolated and in partially sinergy association with chloramphenicol, being able to drastically reduce the population density of Salmonella spp. at levels more accentuated than ampicillin, chloramphenicol and levofloxacin used isolated. The evaluation of antibiofilm potential against Salmonella spp. strains revealed that EAE was the most efective extract, being able to inhibity the bacterial cells adhesion in the polystyrene surface. In relation to the acute toxicity screening, EAE was unable to make the microcrustacean A. salina unfeasible in concentrations ranging from 500 to 5000 µg/mL, showing low toxicity. Together, these results suggest that P. hydropiperoides is a natural source of active substances with antibacterial potential, which add scientific support for its popular use, mainly as antidisenteric, due to its effect on the Salmonella strains tested.