RESUMO
Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck (Piperaceae) is a medicinal plant traditionally used in Brazil to treat infectious diseases. The extracts obtained of the leaves from P. regnellii were investigated for their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA). The ethyl acetate extract presented a good activity against MRSA, with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of 16 microg/mL. Based on this finding, the ethyl acetate extract was fractionated by silica gel column chromatography into nine fractions. The hexane fraction was active against MRSA (MIC at 4 microg/mL). Further column chromatography separation of the hexane fraction afforded the pure compound eupomatenoid-5. The structure of the compound was established by spectral data (1H and 13C NMR HSQC, HMBC, gNOE, IR and MS). Eupomatenoid-5 was the only compound active on the bacterium. The antibacterial property of P. regnellii extract provides preliminary scientific validation for the traditional medicinal use of this plant. The active compound eupomatenoid-5 should be further studied in animal models to verify in vivo efficacy and toxicity.
Assuntos
Antibacterianos/farmacologia , Benzofuranos/farmacologia , Lignanas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Fenóis/farmacologia , Piper/química , Extratos Vegetais/farmacologia , Acetatos/química , Antibacterianos/química , Benzofuranos/análise , Cromatografia em Gel , Lignanas/análise , Staphylococcus aureus Resistente à Meticilina/ultraestrutura , Microscopia Eletrônica de Varredura , Fenóis/análise , Extratos Vegetais/química , Folhas de Planta/química , Sílica Gel , Dióxido de SilícioRESUMO
A espécie Pereskia grandifolia Haworth (Cactaceae), conhecida popularmente como ora-pro-nóbis, foi avaliada quanto às suas propriedades antioxidantes e susceptibilidade antimicrobiana. As propriedades antioxidantes foram avaliadas pelo método de inibição do radical livre 2,2-difenil-1-picrilidrazil (DPPH?). Os extratos das folhas de P. grandifolia (1000 ?g/mL) apresentaram propriedades antioxidantes entre 10 e 30% de inibição. Dentre os extratos avaliados, o diclorometânico e o acetato de etila apresentaram maior capacidade de seqüestro de radicais livres de DPPH' (25 e 30% de inibição, respectivamente). A susceptibilidade antimicrobiana foi avaliada pelo método de microdiluição. Não se observau atividade antibacteriana frente a Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6623) e Pseudomonas aeruginosa (ATCC 27853), nem atividade antifúngica frente a Candida albicans (ATCC 10231).
The specie Pereskia grandifolia Haworth (Cactaceae), popularly known as ora-pro-nóbis, was evaluated for their antioxidant property and antibacterial susceptibility. The antioxidant properties were evaluated by inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The P. grandifolia leaves extracts (1000 μg/mL) shown antioxidant properties, with inhibition varying between 10 and 30% of control. Among the tested extracts, the dichloromethane and ethyl acetate extracts presented higher free radicals scavenging capability in the DPPH method (25 and 30% of inhibition, respectively). Antibacterial activity was not observed against the Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6623) and Pseudomonas aeruginosa (ATCC 27853), neither antifungal activity against Candida albicans (ATCC 10231).