How to Study Antimicrobial Activities of Plant Extracts: A Critical Point of View

Mahieux, Séverine; Nieto-Bobadilla, M.S.; Houcke, Isabelle; Neut, Christel

doi:10.1007/978-3-319-67045-4_3

Cited by 4 publications

(9 citation statements)

References 22 publications

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“…Kill curves allowed the determination of time-dependent bacteriostatic and bactericidal concentrations of each product [33] (Figure 5).…”

Section: Resultsmentioning

confidence: 99%

“…Post-antibiotic tests highlighted the fragility of the bacterial population after 2 h exposure to the active compounds followed by inactivation, which resulted in a delayed regrowth [33]. The growth retardation is quantified by the difference between the time necessary for each condition to grow from a log10 (T) and the corresponding time for the control (C).…”

Section: Resultsmentioning

confidence: 99%

“…In this context, we evaluated the antibacterial potential of hop extracts and more particularly of three pure compounds isolated from hops (xanthohumol, desmethylxanthohumol and lupulone) towards MRSA, one of the most aggressive agents, with different approaches [33]. We began by a classical MIC determination, which is only an endpoint method, followed by kill-time curves assessing the time dependent effect and synergistic studies, in combination with antibiotics, giving more information on their resistance modifying potential.…”

Section: Discussionmentioning

confidence: 99%

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Phenolic Compounds from Humulus lupulus as Natural Antimicrobial Products: New Weapons in the Fight against Methicillin Resistant Staphylococcus aureus, Leishmania mexicana and Trypanosoma brucei Strains

et al. 2019

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New anti-infective agents are urgently needed to fight microbial resistance. Methicillin-resistant Staphylococcus aureus (MRSA) strains are particularly responsible for complicated pathologies that are difficult to treat due to their virulence and the formation of persistent biofilms forming a complex protecting shell. Parasitic infections caused by Trypanosoma brucei and Leishmania mexicana are also of global concern, because of the mortality due to the low number of safe and effective treatments. Female inflorescences of hop produce specialized metabolites known for their antimicrobial effects but underexploited to fight against drug-resistant microorganisms. In this study, we assessed the antimicrobial potential of phenolic compounds against MRSA clinical isolates, T. brucei and L. mexicana. By fractionation process, we purified the major prenylated chalcones and acylphloroglucinols, which were quantified by UHPLC-UV in different plant parts, showing their higher content in the active flowers extract. Their potent antibacterial action (MIC < 1 µg/mL for the most active compound) was demonstrated against MRSA strains, through kill curves, post-antibiotic effects, anti-biofilm assays and synergy studies with antibiotics. An antiparasitic activity was also shown for some purified compounds, particularly on T. brucei (IC50 < 1 to 11 µg/mL). Their cytotoxic activity was assessed both on cancer and non-cancer human cell lines.

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“…Kill curves allowed the determination of time-dependent bacteriostatic and bactericidal concentrations of each product [33] (Figure 5).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Phenolic Compounds from Humulus lupulus as Natural Antimicrobial Products: New Weapons in the Fight against Methicillin Resistant Staphylococcus aureus, Leishmania mexicana and Trypanosoma brucei Strains

et al. 2019

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“…One of the most promising sources for new antimicrobial compounds can be plant materials (Savoia, 2012;Bragg et al 2018;Mahieux et al 2018). Plant-derived antimicrobials are also considered to be safer compared with synthetic compounds because of their natural origin one of the most prospective ways to combat antibiotic resistance (Abreu et al 2012;Mahieux et al 2018). This strategy may enable reusing conventional antibiotics, which had been cut out from usage due to resistance of infectious agents towards them.…”

Section: Introductionmentioning

confidence: 99%

Novel approach to combat antibiotic resistance: evaluation of some Armenian herb crude extracts for their antibiotic modulatory and antiviral properties

Ginovyan

Trchоunian

2019

J of Applied Microbiology

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Aims One of the strategies to combat antibiotic resistance can be the use of plant materials in combination with antibiotics, taking into account that phytochemicals can act as antibiotic resistance‐modifying agents. This can give a second life to the traditional antibiotics. The aim was to evaluate antibiotic modulatory effect of crude extracts from Agrimonia eupatoria, Hypericum alpestre, Rumex obtusifolius and Sanguisorba officinalis herbs towards several commercial antibiotics using some Gram‐positive and Gram‐negative bacteria. Methods The antibiotic modulatory activity was tested by determining MICs of antibiotics in the absence and presence of plant crude extracts at subinhibitory concentrations. Antiviral potential of different extracts of tested plant materials was also explored by double overlay plaque assay. Results The tested plant crude extracts exhibited high modulatory activity towards used antibiotics. Particularly, high modulatory activity was observed with extracts of H. alpestre and R. obtusifolius. Many plant‐antibiotic combinations induced the decrease in MICs of antibiotics up to ~fourfold indicating synergy. Moreover, the similar change was observed at both subinhibitory concentrations (MIC/2 and MIC/4) of the same plant crude extract. High anti‐phage activity of plants with the exception of Lilium armenum against T4 phage of Escherichia coli C‐T4 was also shown. Conclusions Plant crude extract or commercial antibiotic combinations significantly increased the efficiency of antibiotics. Tested plant materials with exception of L. armenum have antiviral property. Significance and Impact of the Study For the first time, antibiotic modulatory activity of tested herb extracts was shown, which could have potential in practical applications. Tested plant materials with exception of L. armenum could have prospective, as a source of new antiviral compounds.

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“…For example, the Egyptians were using garlic extract in food preservation. There is a continuous rise of interest in the search for antimicrobial agents from plants [14].…”

Section: Introductionmentioning

confidence: 99%

Comparative Efficacy of Aloe vera (Linn) and Aloe schweinfurthii (Baker) Powdered Leaf Extracts in the Control of Some Plant Fungal Pathogens

Alejo

Ajayi

Akinyele

2019

IJBcRR

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Evaluation of the relative efficacy of powdered leaf extracts of Aloe vera (Linn) and Aloe schweinfurthii (Baker) in the control of some plant pathogens was undertaken in this work. Antimicrobial activities of the extracts obtained using cold water, hot water and ethanol were tested against four fungal spp., namely, Alternaria solani, Colletotrichum lindemuthianum, Sclerotium rolfsii and Trichophyton rubrum. The phytochemical screening of the leaf extracts of the two aloe species revealed the presence of bioactive compounds such as alkaloids, tannins, saponins, flavonoids, cardiac glycosides, phytates and oxalates. The extracts were observed to exhibit varying inhibitory effects on the selected fungi. Ethanolic extract of A. vera at 50 mg/ml and 100 mg/ml had the greatest impact on A. solani and C. lindemuthianum respectively. Similarly, cold water extract of A. schweinfurthii at 100 mg/ml was the most effective against S. rolfsii and T. rubrum. However, hot water extract of A. vera was least effective against C. lindemuthianum. Also, the efficacy of cold water extract of A. schweinfurthii at 50 mg/ml was very low against T. rubrum and A. solani. The hot water extract of A. schweinfurthii at 20 mg/ml also showed the least effect against S. rolfsii. Consequently, extracts from both Aloe species can be recommended in the management of the four fungal pathogens evaluated in this study. It is hoped that in no distant future, botanical fungicides would be developed from the two Aloe species.

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How to Study Antimicrobial Activities of Plant Extracts: A Critical Point of View

Cited by 4 publications

References 22 publications

Phenolic Compounds from Humulus lupulus as Natural Antimicrobial Products: New Weapons in the Fight against Methicillin Resistant Staphylococcus aureus, Leishmania mexicana and Trypanosoma brucei Strains

Phenolic Compounds from Humulus lupulus as Natural Antimicrobial Products: New Weapons in the Fight against Methicillin Resistant Staphylococcus aureus, Leishmania mexicana and Trypanosoma brucei Strains

Novel approach to combat antibiotic resistance: evaluation of some Armenian herb crude extracts for their antibiotic modulatory and antiviral properties

Comparative Efficacy of Aloe vera (Linn) and Aloe schweinfurthii (Baker) Powdered Leaf Extracts in the Control of Some Plant Fungal Pathogens

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