| Autor: |
Jepkoech C; Department of Chemistry, School of Pure and Applied Sciences, Kisii University, Kisii, Kenya., Omosa LK; Department of Chemistry, University of Nairobi, Nairobi, Kenya., Nchiozem-Ngnitedem VA; Department of Chemistry, University of Nairobi, Nairobi, Kenya., Kenanda EO; Department of Research and Extension, Kisii University, Kisii, Kenya., Guefack MF; Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon., Mbaveng AT; Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon., Kuete V; Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon., Heydenreich M; Institute of Chemistry, University of Potsdam, Potsdam, Germany. |
| Abstrakt: |
Purification of the aerial parts of Vernonia auriculifera Hiern afforded steroids ( 1-2 ), flavonoids ( 3-5 ), and polyalcohol ( 6 ). Their structures were determined using spectral evidences as well as by comparison with reported data. Iodonitrotetrazolium chloride (INT) colorimetric assay was used to assess the antibacterial activity of the extract and isolates against 13 pathogenic strains. The crude extract showed strong antibacterial activity (MIC < 100 µg/mL) against the tested bacterial strains. When combined with an efflux pump inhibitor phenylalanine beta naphthylamide (PAβN), the inhibition potency of the extract was substantially enhanced with the lowest MIC value at 4 µg/mL. Compounds 5 and 6 showed moderate activity (MIC < 100 µg/mL) against 12/13 (92.3%), and 8/13 (61.5%) bacterial strains, respectively. A minimal bactericidal concentration (MBC)/minimal inhibitory concentration (MIC) ratio ≤ 4 indicated their bactericidal effect against Escherichia coli , Enterbacter aerogenes , Klebsiella pneumoniae , Providencia stuartii , Pseudomonas aeruginosa , and Staphylococcus aureus . |
