Evaluation of acute toxicity, antibacterial activity, and mode of action of the hydroethanolic extract of Piper umbellatum L

作者 da Silva, Ibere Ferreira, Jr.; de Oliveira, Ruberlei Godinho; Soares, Ilsamar Mendes; Alvim, Tarso da Costa; Ascencio, Sergio Donizeti; de Oliveira Martins, Domingos Tabajara

期刊 JOURNAL OF ETHNOPHARMACOLOGY , JAN 10 2014,1:151

DOI 10.1016/j.jep.2013.10.011 PubMed 24189034

摘要 Ethnopharmacological relevance: Piper umbellatum L, Piperaceae, is a shrub that grows up to 3 m high. It is commonly known as capeba or pariparoba in Brazil. Tea prepared using the leaves of this plant is employed in the treatment of infections and inflammatory processes in different countries. Approximately 50 compounds, notably from the flavonoid, alkaloid, terpene, and sterol classes, have been isolated from the leaves of Piper umbellatum. To evaluate the acute toxicity, antibacterial activity, and mode of action of the hydroethanolic extract of Piper umbellatum leaves (HEPu).Materials and methods: Acute toxicity of HEPu against CHO-K1 cells was evaluated using a cytotoxicity assay with Alamar Blue and that against mice was assessed by the Hippocratic test. Antibacterial activity of HEPu was tested using the broth microdilution method using a panel of clinically relevant bacteria, and the effects of HEPu on the bacterial membrane were analyzed in detail. A preliminary phytochemical analysis based on coloration/precipitation was performed according to procedure described in the literature. Secondary metabolites detected were analyzed and confirmed by thin layer chromatography (TLC), spectrophotometry, and high performance liquid chromatography (HPLC).Results: Piper umbellatum did not appear to be toxic in the in vitro (IC50 > 200 mu g/mL) cytotoxicity test. When administered in vivo at doses up to 2000 mg/kg p.o., HEPu did not cause any signs or symptoms of toxicity in mice. It demonstrated a good spectrum of antibacterial activity and its mode of action appeared to be associated with changes in the permeability of bacterial membranes; it led to increased entry of hydrophobic antibiotics, efflux of K, and nucleotide leakage. Preliminary phytochemical analysis revealed the presence of flavonoids, alkaloids, terpenes, and sterols in the extract. Spectrophotometric and HPLC analysis revealed the presence of the flavonoids rutin and quercetin.Conclusion: In summary, HEPu has antibacterial activity and low acute toxicity in vitro and in vivo. Its mode of action appears to be associated with changes in the permeability of the bacterial cell wall and cytoplasmic membrane, which can at least be partly attributed to the flavonoids present in the extract. (C) 2013 Elsevier Ireland Ltd. All rights reserved.