Olive Monique F Demgne1, Francois Damen2, Aimé G Fankam3, Michel-Gael F Guefack4, Brice E N Wamba5, Paul Nayim6, Armelle T Mbaveng7, Gabin T M Bitchagno8, Léon Azefack Tapondjou9, Veronique B Penlap10, Pierre Tane11, Thomas Efferth12, Victor Kuete13. 1. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon; Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon. Electronic address: princessdemleur@yahoo.fr. 2. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: francodamen@yahoo.fr. 3. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: agfankam@yahoo.fr. 4. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: michelfofack@gmail.com. 5. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: wambaelvis@yahoo.fr. 6. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: nayimpaul@yahoo.fr. 7. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: armbatsa@yahoo.fr. 8. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: bmgt198716@ymail.com. 9. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: tapondjou2001@yahoo.fr. 10. Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon. Electronic address: v.pemlap@yahoo.fr. 11. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: ptane@yahoo.fr. 12. Department of Pharmaceutical Biology, Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University, Staudinger Weg 5, 55128, Mainz, Germany. Electronic address: efferth@uni-mainz.de. 13. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon. Electronic address: kuetevictor@yahoo.fr.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Infections due to multidrug-resistant (MDR) bacteria constitute a real problem in the public health worldwide. Hypericum roeperianum Schimp. ex A. Rich (Hypericaceae) is used traditionally for treatment of various ailments such as abdominal pains, constipation, diarrhea, indigestion, nausea, and bacterial diseases. AIM OF THE STUDY: This study was aimed at investigating the antibacterial and antibiotic-modifying activity of the crude methanol extracts (HRB), ethyl-acetate soluble fraction (HRBa), residual material (HRBb), and 11 compounds from the bark of Hypericum roeperianum against multi-drug resistant (MDR) bacteria expressing active efflux pumps. MATERIALS AND METHODS: The antibacterial activity, the efflux pump effect using the efflux pump inhibitor (EPI), phenylalanine-arginine-ß-naphthylamide (PAβN), as well as the antibiotic-modifying activity of samples were determined using the broth micro-dilution method. Spectrophotometric methods were used to evaluate the effects of HRB and 8,8-bis(dihydroconiferyl) diferulate (11) on bacterial growth, and bacterial membrane damage, whereas follow-up of the acidification of the bacterial culture was used to study their effects on bacteria proton-ATPase pumps. RESULTS: The crude extract (HRB), HRBa, and HRBb had selective antibacterial activity with MICs ranging from 16 to 512 μg/mL. Phytochemical 11 displayed the best antibacterial activity (0.5 ≤ MIC ≤ 2 μg/mL). The activity of HRB and 11 in the presence of EPI significantly increased on the tested bacteria strains (up to 32-fold). The activity of cloxacillin (CLO), doxycycline (DOX), and tetracycline (TET), was considerably improved (up to 64-fold) towards the multidrug-resistant Enterobacter aerogenes EA-CM64 strain. The crude extract (HRB) and 11 induced the leakage of bacterial intracellular components and inhibited the proton-ATPase pumps. CONCLUSIONS: The crude extract (HRB) and 8,8-bis(dihydroconiferyl)diferulate from the bark of Hypericum roeperianum are good antibacterial candidates that deserve further investigations to achieve antibacterial drugs to fight infections involving MDR bacteria.
ETHNOPHARMACOLOGICAL RELEVANCE: Infections due to multidrug-resistant (MDR) bacteria constitute a real problem in the public health worldwide. Hypericum roeperianum Schimp. ex A. Rich (Hypericaceae) is used traditionally for treatment of various ailments such as abdominal pains, constipation, diarrhea, indigestion, nausea, and bacterial diseases. AIM OF THE STUDY: This study was aimed at investigating the antibacterial and antibiotic-modifying activity of the crude methanol extracts (HRB), ethyl-acetate soluble fraction (HRBa), residual material (HRBb), and 11 compounds from the bark of Hypericum roeperianum against multi-drug resistant (MDR) bacteria expressing active efflux pumps. MATERIALS AND METHODS: The antibacterial activity, the efflux pump effect using the efflux pump inhibitor (EPI), phenylalanine-arginine-ß-naphthylamide (PAβN), as well as the antibiotic-modifying activity of samples were determined using the broth micro-dilution method. Spectrophotometric methods were used to evaluate the effects of HRB and 8,8-bis(dihydroconiferyl) diferulate (11) on bacterial growth, and bacterial membrane damage, whereas follow-up of the acidification of the bacterial culture was used to study their effects on bacteria proton-ATPase pumps. RESULTS: The crude extract (HRB), HRBa, and HRBb had selective antibacterial activity with MICs ranging from 16 to 512 μg/mL. Phytochemical 11 displayed the best antibacterial activity (0.5 ≤ MIC ≤ 2 μg/mL). The activity of HRB and 11 in the presence of EPI significantly increased on the tested bacteria strains (up to 32-fold). The activity of cloxacillin (CLO), doxycycline (DOX), and tetracycline (TET), was considerably improved (up to 64-fold) towards the multidrug-resistant Enterobacter aerogenes EA-CM64 strain. The crude extract (HRB) and 11 induced the leakage of bacterial intracellular components and inhibited the proton-ATPase pumps. CONCLUSIONS: The crude extract (HRB) and 8,8-bis(dihydroconiferyl)diferulate from the bark of Hypericum roeperianum are good antibacterial candidates that deserve further investigations to achieve antibacterial drugs to fight infections involving MDR bacteria.
Authors: Michel-Gael F Guefack; Marcelle O Ngangoue; Armelle T Mbaveng; Paul Nayim; Jenifer R N Kuete; Carine M N Ngaffo; Godloves F Chi; Bathelemy Ngameni; Bonaventure T Ngadjui; Victor Kuete Journal: BMC Complement Med Ther Date: 2022-07-20
Authors: Cédric M Mouzié; Michel-Gael F Guefack; Boris Y Kianfé; Héritier U Serondo; Beaudelaire K Ponou; Xavier Siwe-Noundou; Rémy B Teponno; Rui W M Krause; Victor Kuete; Léon A Tapondjou Journal: Pharmaceuticals (Basel) Date: 2022-06-07