We evaluated the antibacterial activities of the crude methanol extract, fractions (I-V) obtained after acid-base extraction and pure compounds from the stem bark of Aspidosperma ramiflorum. The minimum inhibitory concentration (MIC) was determined by the microdilution technique in Mueller-Hinton broth. Inoculates were prepared in this medium from 24-h broth cultures of bacteria (10(7) CFU/mL). Microtiter plates were incubated at 37ºC and the MICs were recorded after 24 h of incubation. Two susceptibility endpoints were recorded for each isolate. The crude methanol extract presented moderate activity against the Gram-positive bacteria B. subtilis (MIC = 250 µg/mL) and S. aureus (MIC = 500 µg/mL), and was inactive against the Gram-negative bacteria E. coli and P. aeruginosa (MIC > 1000 µg/mL). Fractions I and II were inactive against standard strains at concentrations of <=1000 µg/mL and fraction III displayed moderate antibacterial activity against B. subtilis (MIC = 500 µg/mL) and S. aureus (MIC = 250 µg/mL). Fraction IV showed high activity against B. subtilis and S. aureus (MIC = 15.6 µg/mL) and moderate activity against E. coli and P. aeruginosa (MIC = 250 µg/mL). Fraction V presented high activity against B. subtilis (MIC = 15.6 µg/mL) and S. aureus (MIC = 31.3 µg/mL) and was inactive against Gram-negative bacteria (MIC > 1000 µg/mL). Fractions III, IV and V were then submitted to bioassay-guided fractionation by silica gel column chromatography, yielding individual purified ramiflorines A and B. Both ramiflorines showed significant activity against S. aureus (MIC = 25 µg/mL) and E. faecalis (MIC = 50 µg/mL), with EC50 of 8 and 2.5 µg/mL for ramiflorines A and B, respectively, against S. aureus. These results are promising, showing that these compounds are biologically active against Gram-positive bacteria.
The essential oil of Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck Piparaceae leaves, which were collected at a tree farm named Horto de Plantas Medicinais of the Universidade Estadual de Maringá, was obtained by hydrodistillation. A preliminary analysis by GC/MS was carried out. b-mirceno (70%) was identified as the main constituent by comparing MS and 13C NMR with the literature data. Four neolignans were isolated from the leaves and identified: eupomatenoid-6, eupomatenoid-5, eupomatenoid-3 and conocarpan. Their structures were established by extensive ¹H and 13C NMR, ¹H x ¹H - COSY, HETCOR, HMBC, gNOE and MS spectral studies.
O óleo essencial das folhas de Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck Piparaceae, coletadas no Horto de Plantas Medicinais da Universidade Estadual de Maringá, foi obtido por hidrodestilação. Uma análise preliminar por CG/EM e RMN 13C foi realizada. O b-mirceno (70%) foi identificado como componente majoritário através da comparação dos espectros de massa e RMN 13C com dados da literatura. Quatro neolignanas foram isoladas do extrato hidroetanólico das folhas e identificadas: eupomatenóide-6, eupomatenóide-5, eupomatenóide-3 e conocarpano. As estruturas dessas substâncias foram estabelecidas por meio de estudos de RMN ¹H e 13C, ¹H x ¹H - COSY, HETCOR, HMBC, gNOE e EM.
Extracts of 13 Brazilian medicinal plants were screened for their antimicrobial activity against bacteria and yeast. Of these, 10 plant extracts showed varied levels of antibacterial activity. Five of the plant extracts presented compounds with Rf values similar to the antibacterial compounds visible on bioautogram. Of these, three plants belong to the Compositae family. This may mean that the same compounds are responsible for the antibacterial activity in these plants. Anticandidal activity was detected in 9 plant extracts. The results might explain the ethnobotanical use of the studied species for the treatment of various infectious diseases.
Foram selecionados extratos de 13 plantas utilizadas na medicina popular brasileira para avaliar a atividade antimicrobiana. Destes, 10 extratos apresentaram níveis variados de atividade antibacteriana. Cinco dos extratos testados, apresentaram compostos com valores de Rf similares a de compostos antibacterianos visíveis na bioautografia. Três destas plantas pertencem à família Compositae indicando que o mesmo composto pode ser responsável pela atividade antibacteriana destas plantas. Atividade anticandida foi observada em 9 extratos de plantas. Os resultados podem explicar o uso etnobotânico das espécies estudadas para o tratamento de várias doenças infecciosas.
Two flavan-3-ols and one proanthocyanidins have been isolated from the stem bark of Stryphnodendron polyphyllum Mart., which is traditionally used in Brazil against various diseases. The structure was determined on the basis of spectroscopic data including 1-D (¹H, 13C) and 2-D NMR (¹H/¹H COSY) and MS. The antibacterial activities of an acetone:water and semipurified extracts from the stem bark of Stryphnodendron polyphyllum Mart. were evaluated. Both the crude and semipurified extracts showed activity against Bacillus subtilis and Staphylococcus aureus. Quality control was determined using several pharmacopoeial assay.