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Antimicrobial Activities of a Plethora of Medicinal Plant Extracts and Hydrolates against Human Pathogens and Their Potential to Reverse Antibiotic Resistance.

Njimoh DL, Assob JC, Mokake SE, Nyhalah DJ, Yinda CK, Sandjon B - Int J Microbiol (2015)

Bottom Line: Here we (i) assessed the effects of extracts/hydrolates of some medicinal plants on pathogenic microorganisms and (ii) evaluated the inhibitory potential of the most active ones in combination with antibiotics.These results justify the use of these plants in traditional medicine and the practice of supplementing decoctions/concoctions with conventional antibiotics.Nauclea pobeguinii (E30), the most active and synergistic of all these extracts, and some hydrolates with antimicrobial activity need further exploration for the development of novel antimicrobials.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, South West Region, Cameroon.

ABSTRACT
Microbial infections till date remain a scourge of humanity due to lack of vaccine against some infections, emergence of drug resistant phenotypes, and the resurgence of infections amongst others. Continuous quest for novel therapeutic approaches remains imperative. Here we (i) assessed the effects of extracts/hydrolates of some medicinal plants on pathogenic microorganisms and (ii) evaluated the inhibitory potential of the most active ones in combination with antibiotics. Extract E03 had the highest DZI (25 mm). Extracts E05 and E06 were active against all microorganisms tested. The MICs and MBCs of the methanol extracts ranged from 16.667 × 10(3) μg/mL to 2 μg/mL and hydrolates from 0.028 to 333333 ppm. Extract E30 had the highest activity especially against S. saprophyticus (MIC of 6 ppm) and E. coli (MIC of 17 ppm). Combination with conventional antibiotics was shown to overcome resistance especially with E30. Analyses of the extracts revealed the presence of alkaloids, flavonoids, triterpenes, steroids, phenols, and saponins. These results justify the use of these plants in traditional medicine and the practice of supplementing decoctions/concoctions with conventional antibiotics. Nauclea pobeguinii (E30), the most active and synergistic of all these extracts, and some hydrolates with antimicrobial activity need further exploration for the development of novel antimicrobials.

No MeSH data available.


Related in: MedlinePlus

MICs of extracts and hydrolates against gram negative bacteria species: Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi. 1–30 = E01–E30.
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fig3: MICs of extracts and hydrolates against gram negative bacteria species: Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi. 1–30 = E01–E30.

Mentions: The minimal inhibitory concentration (MIC) of 17 extracts and 13 hydrolates were determined for various test organisms including the clinical fungal isolate Tricophyton rubrum. The MICs ranged from 2 μg/mL to 16.667 mg/mL and 333333 ppm to 6 ppm, respectively, for crude extracts and hydrolates and liquid extracts. The MICs and MBCs of the extracts and hydrolates/liquid extracts are summarized in Tables 4 and 5, respectively. MIC < 100 μg/mL was considered significant. Extracts E02, E03, and E15 had similar susceptibility trends with both fungal species while E01, E11, E18-E19, and E21–E27 did not show any activity against either of the two fungi (Tables 4 and 5). Though both fungi showed similar trends, T. rubrum was not susceptible to extract E16 while C. albicans was (MIC = 12346 ppm) (Figure 1). Also for almost all the active extracts, the MICs for T. rubrum were relatively lower. Extract E30 had an overall lowest MIC against T. rubrum (MIC = 457 ppm). Extract E30 had the lowest MIC (most active) against gram positive bacteria. Staphylococcus saprophyticus was the most susceptible gram positive bacteria compared to S. aureus and S. epidermidis (Figure 2). Escherichia coli was the most susceptible of the gram negative bacteria (Figure 3). Though K. pneumoniae and S. typhi had similar susceptibility vis-à-vis a few extracts (E05, E08, E10, E13, and E30), S. typhi was more susceptible than K. pneumoniae (Figure 3). Extracts E29 and E30 were the most active extracts against gram negative bacteria while extracts E11 and E18 were only active against E. coli. Extract E16 was the only extract that did not show activity against E. coli (the most susceptible specie) as well as against K. pneumoniae (Figure 3). Overall, extract E10 had the lowest MIC with gram negative bacteria species. Some MIC wells which showed growth inhibition also showed bacterial growth on solid nutrient agar. No MBC was recorded for such wells within the concentration ranges tested showing that the active samples were only bacteriostatic.


Antimicrobial Activities of a Plethora of Medicinal Plant Extracts and Hydrolates against Human Pathogens and Their Potential to Reverse Antibiotic Resistance.

Njimoh DL, Assob JC, Mokake SE, Nyhalah DJ, Yinda CK, Sandjon B - Int J Microbiol (2015)

MICs of extracts and hydrolates against gram negative bacteria species: Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi. 1–30 = E01–E30.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4477429&req=5

fig3: MICs of extracts and hydrolates against gram negative bacteria species: Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi. 1–30 = E01–E30.
Mentions: The minimal inhibitory concentration (MIC) of 17 extracts and 13 hydrolates were determined for various test organisms including the clinical fungal isolate Tricophyton rubrum. The MICs ranged from 2 μg/mL to 16.667 mg/mL and 333333 ppm to 6 ppm, respectively, for crude extracts and hydrolates and liquid extracts. The MICs and MBCs of the extracts and hydrolates/liquid extracts are summarized in Tables 4 and 5, respectively. MIC < 100 μg/mL was considered significant. Extracts E02, E03, and E15 had similar susceptibility trends with both fungal species while E01, E11, E18-E19, and E21–E27 did not show any activity against either of the two fungi (Tables 4 and 5). Though both fungi showed similar trends, T. rubrum was not susceptible to extract E16 while C. albicans was (MIC = 12346 ppm) (Figure 1). Also for almost all the active extracts, the MICs for T. rubrum were relatively lower. Extract E30 had an overall lowest MIC against T. rubrum (MIC = 457 ppm). Extract E30 had the lowest MIC (most active) against gram positive bacteria. Staphylococcus saprophyticus was the most susceptible gram positive bacteria compared to S. aureus and S. epidermidis (Figure 2). Escherichia coli was the most susceptible of the gram negative bacteria (Figure 3). Though K. pneumoniae and S. typhi had similar susceptibility vis-à-vis a few extracts (E05, E08, E10, E13, and E30), S. typhi was more susceptible than K. pneumoniae (Figure 3). Extracts E29 and E30 were the most active extracts against gram negative bacteria while extracts E11 and E18 were only active against E. coli. Extract E16 was the only extract that did not show activity against E. coli (the most susceptible specie) as well as against K. pneumoniae (Figure 3). Overall, extract E10 had the lowest MIC with gram negative bacteria species. Some MIC wells which showed growth inhibition also showed bacterial growth on solid nutrient agar. No MBC was recorded for such wells within the concentration ranges tested showing that the active samples were only bacteriostatic.

Bottom Line: Here we (i) assessed the effects of extracts/hydrolates of some medicinal plants on pathogenic microorganisms and (ii) evaluated the inhibitory potential of the most active ones in combination with antibiotics.These results justify the use of these plants in traditional medicine and the practice of supplementing decoctions/concoctions with conventional antibiotics.Nauclea pobeguinii (E30), the most active and synergistic of all these extracts, and some hydrolates with antimicrobial activity need further exploration for the development of novel antimicrobials.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, South West Region, Cameroon.

ABSTRACT
Microbial infections till date remain a scourge of humanity due to lack of vaccine against some infections, emergence of drug resistant phenotypes, and the resurgence of infections amongst others. Continuous quest for novel therapeutic approaches remains imperative. Here we (i) assessed the effects of extracts/hydrolates of some medicinal plants on pathogenic microorganisms and (ii) evaluated the inhibitory potential of the most active ones in combination with antibiotics. Extract E03 had the highest DZI (25 mm). Extracts E05 and E06 were active against all microorganisms tested. The MICs and MBCs of the methanol extracts ranged from 16.667 × 10(3) μg/mL to 2 μg/mL and hydrolates from 0.028 to 333333 ppm. Extract E30 had the highest activity especially against S. saprophyticus (MIC of 6 ppm) and E. coli (MIC of 17 ppm). Combination with conventional antibiotics was shown to overcome resistance especially with E30. Analyses of the extracts revealed the presence of alkaloids, flavonoids, triterpenes, steroids, phenols, and saponins. These results justify the use of these plants in traditional medicine and the practice of supplementing decoctions/concoctions with conventional antibiotics. Nauclea pobeguinii (E30), the most active and synergistic of all these extracts, and some hydrolates with antimicrobial activity need further exploration for the development of novel antimicrobials.

No MeSH data available.


Related in: MedlinePlus