Characterization of n-Hexane sub-fraction of Bridelia micrantha (Berth) and its antimycobacterium activity

<p>Abstract</p> <p>Background</p> <p>Tuberculosis, caused by <it>Mycobacterium tuberculosis </it>(MTB), is the most notified disease in the world. Development of resistance to first line drugs by MTB is a public health concern. As a result, there is the search for new and novel sources of antimycobacterial drugs for example from medicinal plants. In this study we determined the <it>in vitro </it>antimycobacterial activity of <it>n</it>-Hexane sub-fraction from <it>Bridelia micrantha </it>(Berth) against MTB H₃₇Ra and a clinical isolate resistant to all five first-line antituberculosis drugs.</p> <p>Methods</p> <p>The antimycobacterial activity of the <it>n</it>-Hexane sub-fraction of ethyl acetate fractions from acetone extracts of <it>B. micrantha </it>barks was evaluated using the resazurin microplate assay against two MTB isolates. Bioassay-guided fractionation of the ethyl acetate fraction was performed using 100% <it>n</it>-Hexane and Chloroform/Methanol (99:1) as solvents in order of increasing polarity by column chromatography and Resazurin microtiter plate assay for susceptibility tests.</p> <p>Results</p> <p>The <it>n</it>-Hexane fraction showed 20% inhibition of MTB H₃₇Ra and almost 35% inhibition of an MTB isolate resistant to all first-line drugs at 10 μg/mL. GC/MS analysis of the fraction resulted in the identification of twenty-four constituents representing 60.5% of the fraction. Some of the 24 compounds detected included Benzene, 1.3-bis (3-phenoxyphenoxy (13.51%), 2-pinen-4-one (10.03%), N(b)-benzyl-14-(carboxymethyl) (6.35%) and the least detected compound was linalool (0.2%).</p> <p>Conclusions</p> <p>The results show that the <it>n-</it>Hexane fraction of <it>B. micrantha </it>has antimycobacterial activity.</p

Optimum extraction process of polyphenols from Bridelia grandis stem bark using experimental design

Euphorbiaceae barks are known to contain an appreciable amount of polyphenolic compounds responsible for several biological activities. Preliminary extraction from Bridelia grandis stem bark afforded high content of polyphenols, determined by spectrophotometric methods such as Folin–Ciocalteu (for total phenols, TP) and n-butanol-HCl (for condensed tannins, CT). A preliminary Plackett–Burman screening design was used to identify the key factors that influence the TP and CT extraction. Between all the variables known to influence the extraction from vegetable matrixes, six were selected; maceration was chosen as traditional extraction methodology. To investigate the effect of solvents and extraction method, methanol, acetone 70% (v/v in water), centrifugation and ultrasound were chosen. A full factorial design 23 was applied to optimize the extraction procedure. The responses were obtained analyzing the extracts for their TP and CT contents determined by the above-mentioned spectrophotometric methods. The results confirm that, within the explored domain, the optimum solvent is methanol and the optimum method is one-cycle centrifugation. Finally, it was also compared with the effect of maceration on the considered responses. It has never given results better than centrifugation, whereas in the case of CT it represents an advantage to employ a threecycle centrifugation instead of one

Validation of use of a traditional remedy from Bridelia grandis (Pierre ex Hutch) stem bark against oral Streptococci.

Aim of the study: Bridelia grandis (Pierre ex Hutch) (Euphorbiaceae) is amedicinal plant traditionally used in Cameroon by pygmies Baka as a remedy for oral cavity affection. Bioassay-guided stem bark extracts were investigated for their in vitro antimicrobial properties as well as their phytochemical constituents. Materials and methods: The first extractionwas carried out according to the traditional use. Further extraction swere carried out with solvents of different polarity such as methanol (MeOH), ethyl acetate (EtOAc)and mixtures of MeOH–H2O. The antimicrobial activity of the extracts against oral Streptococci was evaluated on the basis of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by the macrodilution method; the bacterial surface hydrophobicity was also evaluated. Results: Water, methanol and mixtures methanol–water extracts, exhibited antibacterial activity with MIC between 0.5 and 2 mg/ml justifying the traditional use of Bridelia grandis stem bark for oral cavity affection. Preliminary phytochemical analysiswas performed on the most active extract (methanol) using appropriate tests and well established analytical screening methods, such as TLC and RP-HPLC/DAD.Conclusions: The data obtained indicate that tannins constitute the chemical family responsible for the biological activity