INVESTIGAÇÃO FITOQUÍMICA, ANTIMICROBIANA E CITOTÓXICA DO EXTRATO ETANÓLICO DE PIPER ADUNCUM IN VITRO

Abstract

Studies show that phytochemicals present in species of the genus Piper may have anti-inflammatory, antitumor, antimicrobial, and antiviral actions. Piper aduncum tea is used in folk medicine, however, few studies prove bioactive products in ethanolic extract of leaves of this species. In this research, the phytochemical composition, antioxidant, antimicrobial and cytotoxic activity of ethanolic extract of P. aduncum leaves were investigated. The secondary metabolite classes were determined by HPLC-DAD and antioxidant activity was determined by DPPH (2,2diphenyl-1-picrylhydrazyl) free radical scavenging method. Antimicrobial activity was performed by means of disk diffusion and broth microdilution tests against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant carbapenemase-producing Klebsiella pneumoniae (KP-KPC) and Escherichia coli ATCC-25922. For cytotoxic investigation, MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide) assay was performed using extract (62.50, 125, 250 and 500µg/mL) on intestinal carcinoma cells (HT29). Then, comet assay and apoptosis assay were performed at the same concentrations. The secondary metabolites detected were phenolic compounds and flavonoids. The antioxidant activity of the extract was higher than 50%. The extract did not show inhibitory activity against Escherichia coli and MRSA, but against KP-KPC a growth inhibition halo of 8.5 ± 0.7 mm and 10.5 ± 2.12 mm was observed at concentrations of 500 µg/disc and 2000 µg/disc, respectively. The minimum inhibitory concentration on KP-KPC was high (greater than 2000 µg/mL) and the viability of HT29 cells was not altered at concentrations from 62.50 to 250 µg/m. At the concentration of 500 µg/mL the extract was cytotoxic (MTT) and genotoxic (comet) with an average of 47.7±2.9 injured cells, however, in the in situ apoptosis test, no cell death was observed (HT29). In the ethanolic extract of P. aduncum leaves are present phytochemical compounds of proven pharmacological action, antioxidant and cytotoxic properties. It is believed that the use of other solvents (besides ethanol) and a larger number of microorganisms are needed to determine the antimicrobial potential of P. aduncum.