Browsing Faculty of Science by Author "Ambassa, P."
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Mbaveng, A.; Ngameni, B.; Kuete, V.; Simo, I.K.; Ambassa, P.; Roy, R.; Bezabili, M.; Etoa, F.X.; Ngadjui, B.; Abegaz, B.; Meyer, J.J.M.; Lall, N.; Beng, V.P. (Elsevier Ireland Ltd. http://www.elsevier.com/wps/find/journaldescription.cws_home/506035/description#description, NaN, 2008)[more][less]
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 19.06 g/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 0.3 g/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 (0.3 g/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. URI: http://hdl.handle.net/10311/234 Files in this item: 2
Antimicrobial activity of the crude.pdf (2.258Mb)license.txt (1.998Kb) -
Kuete, V.; Ngameni, B.; Tsafack, A.M.; Ambassa, P.; Simo, I.K.; Bezabih, M.; Etoa, F.; Ngadjui, BT; Abegaz, B.M.; Beng, V.P. (Pharmacologyonline. http://www.pharmacologyonline.org/, NaN, 2007)[more][less]
Abstract: The crude extract from the twigs of Dorstenia elliptica (DET) as well one of the five compounds isolated from this extract namely O-[3-(2, 2-dimethyl-3-oxo-2H-furan-5-yl)-3- hydroxybutyl]bergaptol (5) were tested for their antimicrobial activity against bacteria and fungi. 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 DET prevented the growth of all the 22 tested microbial species while the two tested compounds showed selective activity. At the tested MIC interval ranged from 1.22 to 156.25 μg/ml for the crude extracts and 0.08 to 39.06 μg/ml for the compounds, the activity of DET was noted on 20 of the 22 microbial species. The antimicrobial activities of DET as well as that compound 5 are being reported for the first time. The overall results provide promising baseline information for the potential use of the crude extract in the treatment of bacterial and fungal infections. URI: http://hdl.handle.net/10311/287 Files in this item: 1
ANTIMICROBIAL ACTIVITY OF THE.pdf (4.398Mb) -
Abegaz, B.M.; Ngadjui, B.T.; Folefoc, G.N.; Fotso, S.; Ambassa, P.; Bezabih, M.; Dongo, E.; Rise, F.; Petersen, D. (Elsevier Ltd. www.elsevier.com/locate/phytochem, NaN, 2003)[more][less]
Abstract: A monoprenylated flavan and two monoterpenoid substituted furanocoumarins were isolated from the twigs of Dorstenia elliptica along with 3-(3,3-dimethylallyl)-4,20,40-trihydroxylchalcone, psoralen, bergapten, O-[3-(2,2-dimethyl-3-oxo-2H-furan-5-yl)butyl] bergaptol, b-sitosterol and its b-d-glucopyranoside. The structure of the flavan was determined as 6(1,1-dimethylallyl)-7,40- dihydroxylflavan and the monoterpenoid substituted furanocoumarins were assigned as O-[3-(2,2-dimethyl-3-oxo-2H-furan-5-yl)-3- hydroxybutyl]-bergaptol and O-[2-(5-hydroxy-2,6,6-trimethyl-3-oxo-2H-pyran-2-yl)ethyl]bergaptol, respectively, using spectroscopic analysis, especially, 2D NMR spectra. URI: http://hdl.handle.net/10311/286 Files in this item: 1
Prenylated flavonoids,.pdf (3.692Mb)
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