The aim of this study was to investigate antibacterial activity of Origanum compactum essential oils collected at three phenological stages on Escherichia coli and Bacillus subtilis. The antibacterial activity was eva...The aim of this study was to investigate antibacterial activity of Origanum compactum essential oils collected at three phenological stages on Escherichia coli and Bacillus subtilis. The antibacterial activity was evaluated using the agar-well diffusion assay. The MIC and MBC values were determined using the micro-dilution assay. The investigation of the antibacterial action was carried out by the evaluation of the effect of O. compactum essential oils on the antibacterial kinetic growth, the integrity of cell membrane and permeability of the cell membrane. The anti-quorum sensing activity was tested by the inhibition of the biofilm formation. The findings of this study showed that O. compactum essential oil has potent antibacterial activities against E. coli and B. subtilis. The lowest inhibition value against B. subtilis was obtained with O. compactum essential oil at the post-flowering stage (MIC=MBC=0.0312%(v/v)). The antibacterial mechanisms of O. compactum essential oils are related to the disturbing of the cell membrane integrity and the increasing of the membrane permeability, which leads to the leakage of genetic materials (DNA and RNA). Moreover, O. compactum essential oils inhibited the formation of the biofilms, a phenotype that has been known to be quorum sensing regulated.展开更多
Traditional treatment of infectious diseases is based on compounds that aim to kill or inhibit bacterial growth. The bacterial resistance against antibiotics is a serious issue for public health. Today, new therapeuti...Traditional treatment of infectious diseases is based on compounds that aim to kill or inhibit bacterial growth. The bacterial resistance against antibiotics is a serious issue for public health. Today, new therapeutic targets other than the bacterial wall were deciphered. Quorum sensing or bacterial pheromones are molecules called auto-inducer secreted by bacteria to regulate some functions such as antibiotic resistance and biofilms formation. This therapeutic target is well-studied worldwide, nevertheless the scientific data are not updated and only recent researches started to look into its potential as a target to fight against infectious diseases. A major concern with this approach is the frequently observed development of resistance to antimicrobial compounds. Therefore, this paper aims to provide a current overview of the quorum sensing system in bacteria by revealing their implication in biofilms formation and the development of antibiotic resistance, and an update on their importance as a potential target for natural substances.展开更多
Objective: To determin the chemical compounds of Mentha suaveolens(M. suaveolens) and Pinus halepensis(P. halepensis) essential oils(Eos) and evaluate their antioxidant and antibacterial activities. Methods: The chemi...Objective: To determin the chemical compounds of Mentha suaveolens(M. suaveolens) and Pinus halepensis(P. halepensis) essential oils(Eos) and evaluate their antioxidant and antibacterial activities. Methods: The chemical composition of P. halepensis and M. suaveolens EOs was determined by GC-MS analysis. The antioxidant activity was evaluated using DPPH,ABTS and FRAP assays. The antibacterial effect was tested against 6 bacterial strains using the well diffusion method and micro-dilution assay. Results: The major components of P. halepensis EOs were β-caryophyllene(28.04%),myrcene(23.81%) and α-pinene(12.02%). However,piperitenone oxid(56.28%),piperitenone(11.64%) and pulegone(6.16%) were the major components of M. suaveolens EOs. M. suaveolens EOs showed remarkable antioxidant activities compared with P. halepensis EOs,showing antioxidant capacity values of IC50=(64.76±2.24) μg/mL,IC50=(82.73±3.34) μg/mL,and IC50=(93.35±4.45) μg/mL,revealed by DPPH,ABTS and FRAP assays,respectively. However,P. halepensis EOs showed interesting antibacterial effects against all bacterial strains. The most sensible strains to P. halepensis EOs were Staphylococcus aureus [(34.00±0.50) mm],Listeria monocytogenes [(31.00±1.50)] mm and Proteus mirabilis [(29.00±2.25)mm]. Furthermore,the lowest minimal inhibitory concentration(MIC) and minimal bactericidal concentration(MBC) values were revealed by P. halepensis EOs against Staphylococcus aureus [MIC=MBC=0.125%(v/v)] and Listeria monocytogenes [MIC=MBC=0.25%(v/v)]. Conclusions: P. halepensis and M. suaveolens EOs contain bioactive compounds that could have potential applications against bacterial infections and oxidative stress related diseases as well as for food conservation. However,further investigations are necessary to isolate and investigate the action mechanisms of these bioactive compounds.展开更多
To determine the antioxidant activity of the water (WE), methanol (ME), ethanol (EE) and ethyl acetate extracts (EAE) from the leaves of Cistus monspeliensis, several methods such as 1,1-diphenyl-2-picryhydrazyl (DPPH...To determine the antioxidant activity of the water (WE), methanol (ME), ethanol (EE) and ethyl acetate extracts (EAE) from the leaves of Cistus monspeliensis, several methods such as 1,1-diphenyl-2-picryhydrazyl (DPPH) radical-scavenging assay, 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolorization assay, reducing power assay, metal chelating assay, Thiobarbituric acid test (TBARS) and β-carotene linoleic acid system assay were investigated. Because of the important roles of total phenolics and total flavonoids as antioxidants, the amounts of total phenolics and total flavonoids in the extracts were also determined. The WE and ME showed a higher scavenging activity on the DPPH and ABTS radical. Both extracts also exhibited a strong chelating effect on Fe2+ and performed the best in the reducing power assay. On the other hand, the WE and ME were found to have the higher total phenolic contents (23.13 and 23.25 mg GAE/g of extract respectively) and total flavonoid contents (55.08 and 47.77 mg rutin/g of extract respectively). Thus, both extracts are promising alternatives to synthetic substances as food ingredients with antioxidant activity. The ME and the WE showed the similar levels in phenolic content.展开更多
基金the "Centre National pour la Recherche Scientifique et Technique" (CNRST) "Agence Nationale des Plantes Medicinales et Aromatiques" (ANPMA) for their funding supports
文摘The aim of this study was to investigate antibacterial activity of Origanum compactum essential oils collected at three phenological stages on Escherichia coli and Bacillus subtilis. The antibacterial activity was evaluated using the agar-well diffusion assay. The MIC and MBC values were determined using the micro-dilution assay. The investigation of the antibacterial action was carried out by the evaluation of the effect of O. compactum essential oils on the antibacterial kinetic growth, the integrity of cell membrane and permeability of the cell membrane. The anti-quorum sensing activity was tested by the inhibition of the biofilm formation. The findings of this study showed that O. compactum essential oil has potent antibacterial activities against E. coli and B. subtilis. The lowest inhibition value against B. subtilis was obtained with O. compactum essential oil at the post-flowering stage (MIC=MBC=0.0312%(v/v)). The antibacterial mechanisms of O. compactum essential oils are related to the disturbing of the cell membrane integrity and the increasing of the membrane permeability, which leads to the leakage of genetic materials (DNA and RNA). Moreover, O. compactum essential oils inhibited the formation of the biofilms, a phenotype that has been known to be quorum sensing regulated.
文摘Traditional treatment of infectious diseases is based on compounds that aim to kill or inhibit bacterial growth. The bacterial resistance against antibiotics is a serious issue for public health. Today, new therapeutic targets other than the bacterial wall were deciphered. Quorum sensing or bacterial pheromones are molecules called auto-inducer secreted by bacteria to regulate some functions such as antibiotic resistance and biofilms formation. This therapeutic target is well-studied worldwide, nevertheless the scientific data are not updated and only recent researches started to look into its potential as a target to fight against infectious diseases. A major concern with this approach is the frequently observed development of resistance to antimicrobial compounds. Therefore, this paper aims to provide a current overview of the quorum sensing system in bacteria by revealing their implication in biofilms formation and the development of antibiotic resistance, and an update on their importance as a potential target for natural substances.
基金supported by le Centre National pour la Recherche Scientifique et Technique et l’Agence Nationale des Plantes Médicinales et Aromatiques
文摘Objective: To determin the chemical compounds of Mentha suaveolens(M. suaveolens) and Pinus halepensis(P. halepensis) essential oils(Eos) and evaluate their antioxidant and antibacterial activities. Methods: The chemical composition of P. halepensis and M. suaveolens EOs was determined by GC-MS analysis. The antioxidant activity was evaluated using DPPH,ABTS and FRAP assays. The antibacterial effect was tested against 6 bacterial strains using the well diffusion method and micro-dilution assay. Results: The major components of P. halepensis EOs were β-caryophyllene(28.04%),myrcene(23.81%) and α-pinene(12.02%). However,piperitenone oxid(56.28%),piperitenone(11.64%) and pulegone(6.16%) were the major components of M. suaveolens EOs. M. suaveolens EOs showed remarkable antioxidant activities compared with P. halepensis EOs,showing antioxidant capacity values of IC50=(64.76±2.24) μg/mL,IC50=(82.73±3.34) μg/mL,and IC50=(93.35±4.45) μg/mL,revealed by DPPH,ABTS and FRAP assays,respectively. However,P. halepensis EOs showed interesting antibacterial effects against all bacterial strains. The most sensible strains to P. halepensis EOs were Staphylococcus aureus [(34.00±0.50) mm],Listeria monocytogenes [(31.00±1.50)] mm and Proteus mirabilis [(29.00±2.25)mm]. Furthermore,the lowest minimal inhibitory concentration(MIC) and minimal bactericidal concentration(MBC) values were revealed by P. halepensis EOs against Staphylococcus aureus [MIC=MBC=0.125%(v/v)] and Listeria monocytogenes [MIC=MBC=0.25%(v/v)]. Conclusions: P. halepensis and M. suaveolens EOs contain bioactive compounds that could have potential applications against bacterial infections and oxidative stress related diseases as well as for food conservation. However,further investigations are necessary to isolate and investigate the action mechanisms of these bioactive compounds.
文摘To determine the antioxidant activity of the water (WE), methanol (ME), ethanol (EE) and ethyl acetate extracts (EAE) from the leaves of Cistus monspeliensis, several methods such as 1,1-diphenyl-2-picryhydrazyl (DPPH) radical-scavenging assay, 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolorization assay, reducing power assay, metal chelating assay, Thiobarbituric acid test (TBARS) and β-carotene linoleic acid system assay were investigated. Because of the important roles of total phenolics and total flavonoids as antioxidants, the amounts of total phenolics and total flavonoids in the extracts were also determined. The WE and ME showed a higher scavenging activity on the DPPH and ABTS radical. Both extracts also exhibited a strong chelating effect on Fe2+ and performed the best in the reducing power assay. On the other hand, the WE and ME were found to have the higher total phenolic contents (23.13 and 23.25 mg GAE/g of extract respectively) and total flavonoid contents (55.08 and 47.77 mg rutin/g of extract respectively). Thus, both extracts are promising alternatives to synthetic substances as food ingredients with antioxidant activity. The ME and the WE showed the similar levels in phenolic content.
