Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates
The vast spread of multidrug-resistant bacteria has encouraged researchers to explore new antimicrobial compounds. This study aimed to investigate the phytochemistry and antibacterial activity of <i>Cycas thouarsii</i> R.Br. leaves extract against <i>Klebsiella pneumoniae</i>...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Pharmaceuticals |
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| Online Access: | https://www.mdpi.com/1424-8247/14/8/756 |
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| author | Walaa A. Negm Mona El-Aasr Amal Abo Kamer Engy Elekhnawy |
| author_facet | Walaa A. Negm Mona El-Aasr Amal Abo Kamer Engy Elekhnawy |
| author_sort | Walaa A. Negm |
| collection | DOAJ |
| description | The vast spread of multidrug-resistant bacteria has encouraged researchers to explore new antimicrobial compounds. This study aimed to investigate the phytochemistry and antibacterial activity of <i>Cycas thouarsii</i> R.Br. leaves extract against <i>Klebsiella pneumoniae</i> clinical isolates. The minimum inhibitory concentration (MIC) values of <i>C. thouarsii</i> extract ranged from 4 to 32 µg/mL. The impact of the treatment of the isolates with sub-inhibitory concentrations of <i>C. thouarsii</i> extract was investigated on the bacterial growth, membrane integrity, inner and outer membrane permeability, membrane depolarization, and bacterial morphology using a scanning electron microscope (SEM) and on the efflux activity using qRT-PCR. Interestingly, most <i>K. pneumoniae</i> isolates treated with <i>C. thouarsii</i> extract showed growth inhibition—a decrease in membrane integrity. In addition, we observed various morphological changes, a significant increase in inner and outer membrane permeability, a non-significant change in membrane depolarization, and a decrease in efflux activity after treatment. The phytochemical investigation of <i>C. thouarsii</i> extract revealed the isolation of one new biflavonoid, 5,7,7″,4‴-tetra-<i>O</i>-methyl-hinokiflavone (<b>3</b>), and five known compounds, stigmasterol (<b>1</b>), naringenin (<b>2</b>), 2,3-dihydrobilobetin (<b>4</b>), 4′,4‴-<i>O-</i>dimethyl amentoflavone (<b>5</b>), and hinokiflavone (<b>6</b>), for the first time. Moreover, the pure compounds′ MICs′ ranged from 0.25 to 2 µg/mL. Thus, <i>C. thouarsii</i> could be a potential source for new antimicrobials. |
| first_indexed | 2024-03-10T08:29:17Z |
| format | Article |
| id | doaj.art-656bfe297f174c4ba3dce435bec04fb6 |
| institution | Directory Open Access Journal |
| issn | 1424-8247 |
| language | English |
| last_indexed | 2024-03-10T08:29:17Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Pharmaceuticals |
| spelling | doaj.art-656bfe297f174c4ba3dce435bec04fb62023-11-22T09:11:20ZengMDPI AGPharmaceuticals1424-82472021-08-0114875610.3390/ph14080756Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical IsolatesWalaa A. Negm0Mona El-Aasr1Amal Abo Kamer2Engy Elekhnawy3Pharmacognosy Department, Faculty of Pharmacy, Tanta University, Tanta 31111, EgyptPharmacognosy Department, Faculty of Pharmacy, Tanta University, Tanta 31111, EgyptPharmaceutical Microbiology Department, Faculty of Pharmacy, Tanta University, Tanta 31111, EgyptPharmaceutical Microbiology Department, Faculty of Pharmacy, Tanta University, Tanta 31111, EgyptThe vast spread of multidrug-resistant bacteria has encouraged researchers to explore new antimicrobial compounds. This study aimed to investigate the phytochemistry and antibacterial activity of <i>Cycas thouarsii</i> R.Br. leaves extract against <i>Klebsiella pneumoniae</i> clinical isolates. The minimum inhibitory concentration (MIC) values of <i>C. thouarsii</i> extract ranged from 4 to 32 µg/mL. The impact of the treatment of the isolates with sub-inhibitory concentrations of <i>C. thouarsii</i> extract was investigated on the bacterial growth, membrane integrity, inner and outer membrane permeability, membrane depolarization, and bacterial morphology using a scanning electron microscope (SEM) and on the efflux activity using qRT-PCR. Interestingly, most <i>K. pneumoniae</i> isolates treated with <i>C. thouarsii</i> extract showed growth inhibition—a decrease in membrane integrity. In addition, we observed various morphological changes, a significant increase in inner and outer membrane permeability, a non-significant change in membrane depolarization, and a decrease in efflux activity after treatment. The phytochemical investigation of <i>C. thouarsii</i> extract revealed the isolation of one new biflavonoid, 5,7,7″,4‴-tetra-<i>O</i>-methyl-hinokiflavone (<b>3</b>), and five known compounds, stigmasterol (<b>1</b>), naringenin (<b>2</b>), 2,3-dihydrobilobetin (<b>4</b>), 4′,4‴-<i>O-</i>dimethyl amentoflavone (<b>5</b>), and hinokiflavone (<b>6</b>), for the first time. Moreover, the pure compounds′ MICs′ ranged from 0.25 to 2 µg/mL. Thus, <i>C. thouarsii</i> could be a potential source for new antimicrobials.https://www.mdpi.com/1424-8247/14/8/756biflavonoidseffluxmembrane permeabilitynatural productsSEM5,7,7″,4″-tetra-<i>O</i>-methyl-hinokiflavone |
| spellingShingle | Walaa A. Negm Mona El-Aasr Amal Abo Kamer Engy Elekhnawy Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates Pharmaceuticals biflavonoids efflux membrane permeability natural products SEM 5,7,7″,4″-tetra-<i>O</i>-methyl-hinokiflavone |
| title | Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates |
| title_full | Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates |
| title_fullStr | Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates |
| title_full_unstemmed | Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates |
| title_short | Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of <i>Cycas thouarsii</i> R.Br. Extract against <i>Klebsiella pneumoniae</i> Clinical Isolates |
| title_sort | investigation of the antibacterial activity and efflux pump inhibitory effect of i cycas thouarsii i r br extract against i klebsiella pneumoniae i clinical isolates |
| topic | biflavonoids efflux membrane permeability natural products SEM 5,7,7″,4″-tetra-<i>O</i>-methyl-hinokiflavone |
| url | https://www.mdpi.com/1424-8247/14/8/756 |
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