Antimicrobial activity of the crude extracts and five flavonoids from the twigs of Dorstenia barteri (Moraceae).
ABSTRACT The aim of this study was to evaluate the antimicrobial activity of the crude extract of the twigs of Dorstenia barteri (DBT) as well as that of four of the five flavonoids isolated from this extract. Gram-positive bacteria (six species), Gram-negative bacteria (12 species) and fungi (four species) were used. The agar disc diffusion test was used to determine the sensitivity of the tested samples while the well micro-dilution was used to determine the minimal inhibition concentrations (MIC) and the minimal microbicidal concentration (MMC) of the active samples. The results of the disc diffusion assay showed that DBT, isobavachalcone (1), and kanzonol C (4) prevented the growth of all the 22 tested microbial species. Other compounds showed selective activity. The inhibitory activity of the most active compounds namely compounds 1 and 4 was noted on 86.4% of the tested microorganisms and that of 4-hydroxylonchocarpin (3) was observed on 72.7%. This lowest MIC value of 19.06microg/ml was observed with the crude extract on seven microorganisms namely Citrobacter freundii, Enterobacter aerogens, Proteus mirabilis, Proteus vulgaris, Bacillus megaterium, Bacillus stearothermophilus and Candida albicans. For the tested compounds, the lowest MIC value of 0.3microg/ml (on six of the 22 organisms tested) was obtained only with compound 1, which appeared as the most active compound. This lowest MIC value (0.3microg/ml) is about 4-fold lower than that of the RA, indicating the powerful and very interesting antimicrobial potential of isobavachalcone (1). The antimicrobial activities of DBT, as well as that of compounds 1, 3, 4, amentoflavone (5) are being reported for the first time. The overall results provide promising baseline information for the potential use of the crude extracts from DBT as well as some of the isolated compounds in the treatment of bacterial and fungal infections.
Full-textDOI: · Available from: Victor Kuete, Jun 02, 2015
SourceAvailable from: Emmanuel Mouafo Tekwu[Show abstract] [Hide abstract]
ABSTRACT: Many bacteria are involved in infectious diseases. Most of these bacteria become resistant to the most commonly used synthetic drugs. In Cameroon, natural substance seem to be an alternative to this problem. Thus the aim of this research was to investigate the acute toxicity, antioxidant activities and the in vitro antibacterial of the methanol extract of Ricinodendron heudelotii (Euphorbiaceae) against twelve pathogenic bacteria involved in infectious diseases. The major bioactive components were also screened. The antibacterial activity of the extract was investigated against 12 strains including 10 Gram-and 2 Gram+ bacteria by disc diffusion method and micro dilution method, followed by another agar disc diffusion for the determination of inhibition diameters, the minimum inhibitory concentration (MICs) and the minimum bactericidal concentration (MBC), respectively. 2,2-Diphényl-1-Picrylhydrazyl (DPPH) assay was used to evaluate antiradical activity. The acute toxicity study was performed according to World Health Organization (WHO) protocol. The results of the antibacterial assays indicated that the crude extract was active on 8 of 12 strains tested, with MIC ranging from 188 to 750 µg/ml and MBC from 375 to 1500 µg/ml for the extract from barks of R. heudelotii. Overall, the results of this study indicated that the crude extract represented a potential source of antibacterial and antiradical compounds as shown in previous studies and justified their traditional use in the treatment of bacterial infections and other diseases in Cameroon.Journal of Pharmacognosy and Phytotherapy 07/2014; 6:47-53. DOI:10.5897/JPP2014.0312
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ABSTRACT: A simple and selective specific high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of isobavachalcone (IBC) in rat plasma was developed. Neobavaisoflavone was used as an internal standard (IS). After protein precipitation with acetonitrile (2:1, v/v), the analyte and IS were separated on a 2.6μm Kinetex C18 column (100mm×2.1mm i.d., Phenomenex) by isocratic elution with acetonitrile:water (60:40, v/v) as the mobile phase at a flow rate of 0.2mL/min. An electrospray ionization (ESI) source was applied and operated in the negative ion mode; multiple reactions monitoring (MRM) mode was used for quantification, and the target fragment ions m/z 323.0→118.9 for IBC and m/z 321.1→265.0 for the IS were chosen. Good linearity was observed in the concentration range of 3.79-484.5ng/mL for IBC in rat plasma. The recovery of IBC in plasma was in the range of 81.2-89.8%. Intra-day and inter-day precision were both lower than 10%. This method was suitable for pharmacokinetic studies after oral administration of 80mg/kg IBC in rats. We also obtained pharmacokinetic parameters and concentration-time profiles for IBC after oral administration of IBC in rats. Copyright © 2014 Elsevier B.V. All rights reserved.Journal of Pharmaceutical and Biomedical Analysis 12/2014; 107C:50-55. DOI:10.1016/j.jpba.2014.12.023 · 2.83 Impact Factor