RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Helicteres sacarolha, popularly known in Brazil as 'rosquinha', 'sacarolhas', 'semente-de-macaco', is widely distributed in different phytogeographic zones in Brazil. Preparations from its roots and leaves are employed in popular Brazilian medicine in the treatments of ailments such as peptic ulcer, hypertension among others. Cytotoxicity, acute oral and subchronic toxicity of the hydroethanolic extract of Helicteres sacrolha was investigated as well as the classes of phytochemical present in the extract. MATERIALS AND METHODS: Hydroethanolic (70%) extract of Helicteres sacarolha (HEHs) was prepared by maceration. Potential cytotoxicity was evaluated in CHO-k1 cells. Acute administration of HEHs was done in mice as a single dose up to 5000mg/kg and subchronic oral toxicity study for 30 days in Wistar rats at daily oral doses of 0, 250 and 750mg/kg b.w. Clinical observations and toxicological related parameters were determined every 6 days. Blood was collected for biochemical and hematological analyses, while histological examinations were performed on selected organs. Selected secondary metabolites detected were quantified by UV-spectrophotometry and high performance liquid chromatography (HPLC). RESULTS: The extract was non-cytotoxic to CHO-k1 cells. In acute oral toxicity, there was no mortality or clinical alterations in the female mice, at all doses, except for the transient diarrhea observed at 5000mg/kg acute. Doses up to 2000mg/kg caused no mortality or treatment-related clinical manifestations in the male mice, but treatment-related alterations were however observed at 4000mg/kg, with mortalities recorded at 5000mg/kg. During the subchronic oral toxicity study, no mortality or treatment-related clinical signs were observed. Differences in relative organ weight, hematological parameters and histopathology observations between the treated and the control groups were considered not to be treatment-related. Spectrophotometric analysis revealed the presence of relatively high content of phenolics and flavonoids in HEHs. HPLC analysis confirmed the presence of the quantified compounds and demonstrated the presence of ellagic acid, morin and naringin. CONCLUSION: Our results confirmed that HEHs have a broad safety margin for therapeutic use.
Assuntos
Etnofarmacologia , Malvaceae/química , Extratos Vegetais/toxicidade , Animais , Brasil , Células CHO , Cromatografia Líquida de Alta Pressão/métodos , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Feminino , Masculino , Medicina Tradicional , Camundongos , Extratos Vegetais/administração & dosagem , Ratos , Ratos Wistar , Espectrofotometria Ultravioleta/métodos , Testes de Toxicidade Aguda , Testes de Toxicidade SubcrônicaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Piper umbellatum L., Piperaceae, is a shrub that grows up to 3m 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 µg/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.