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  3. A new flavonol derivative and other compounds from the leaves of Bauhinia thonningii Schum with activity against multidrug-resistant bacteria

A new flavonol derivative and other compounds from the leaves of Bauhinia thonningii Schum with activity against multidrug-resistant bacteria

  • Nat Prod Res. 2023 Aug-Sep;37(16):2653-2661. doi: 10.1080/14786419.2022.2128347.
Guy Raphael Sado Nouemsi 1,  Jean-Bosco Jouda 2,  Peron Bosco Leutcha 1,  Valaire Yemene Matieta 3,  Virginie Flaure Tsague Tankeu 1,  Jenifer Reine Ngnouzouba Kuete 4,  İlhami Çelik 5,  Victor Kuete 3,  Norbert Sewald 6,  Alain Meli Lannang 2 7
Affiliations

Affiliations

  • 1 Department of Chemistry, Faculty of Science, University of Maroua, Maroua, Cameroon.
  • 2 Department of Chemical Engineering, School of Chemical Engineering and Mineral Industries, University of Ngaoundere, Ngaoundere, Cameroon.
  • 3 Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
  • 4 Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
  • 5 Department of Chemistry, Faculty of Science, Eskişehir Technical University, Eskisehir, Turkey.
  • 6 Department of Chemistry, Inorganic and Structural Chemistry, Bielefeld University, Bielefeld, Germany.
  • 7 Department of Chemistry, Higher Teachers Training College, University of Maroua, Maroua, Cameroon.
PMID: 36175178 DOI: 10.1080/14786419.2022.2128347
Abstract

Investigation of the leaves of Bauhinia thonningii Schum led to the isolation and identification of a new flavonol derivative, 6-C-methylquercetin-3,4'-dimethyl ether (1) together with eleven known compounds (2-13), with two of them (10 and 11) obtained as a mixture. Their structures were established by extensive spectroscopic analyses. Antibacterial activity of compound 1 as well as the reference Antibiotic, ciprofloxacin was tested on Gram-negative multidrug-resistant bacteria overexpressing active efflux pumps, and against methicillin-resistant strains of Staphylococcus aureus (MRSA). Samples were tested alone and in combination with an efflux pump inhibitor (EPI), phenylalanine-arginine-β-naphthylamide (PAßN). Results show that when compound 1 was tested alone, its inhibitory effects were obtained on 7/10 tested bacteria with the highest MIC value of 128 µg/mL whilst in the presence of EPI, this activity significantly increase in all the 10 bacteria. An interesting Antibacterial activity was obtained with compound 1 against Klebsiella pneumoniae ATCC11296 (MIC of 4 µg/mL), KP55 and Staphylococcus aureus MRSA6 in the presence of the PaßN.

Keywords

Bauhinia thonningii; antibacterial activity; flavonoids.

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