Antibacterial efficacy of black seed honey in combination with penicillin and amoxiclav against gram-positive bacteria

Background:The emergence of antimicrobial resistance possessesa great threat for the existence of mankind. Antibiotics like penicillin and amoxiclav are at the brink of losing their efficacy entirely in exposure to resistant bacteria. Thus, the present study was aimed to find out the antibacterial efficacy of black seed honey as an alternative natural source which can act independently and boost the efficacy of standard drugs alongside. Methods:Penicillin, amoxiclav and black seed honey were first individually trailedagainst four gram-positive bacteria -Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis andMicrococcus luteus.Afterwards, penicillin and amoxiclav were used in combination with honey and compared the synergistic effects with their individual efficacy. Zones of inhibition from well diffusion method, percentage inhibition, minimum inhibitory and bactericidal concentrations by microdilution method were determined in the present study.Results:Black seed honey alone demonstrated great inhibitory potential against S. aureus (9.7 mm), S. epidermidis (9.9 mm) and M. luteus(9.3 mm) in well diffusion method. Moreover, its combination with amoxiclav showed synergistic effect against all bacteria except S. epidermidis. However, its conjugation with penicillin was not able to produce any synergism as exhibited by zones of inhibition. The lowest concentration (1.56%) of honey applied individually or in combination in microdilution method foundhighly effective which established an inverse dose dependent relationship with efficacy.Conclusions:From the data it can be concluded that the black seed honey is a highly potent natural agent which can be utilized in antimicrobial therapy. However, further investigation is recommended to identify the responsible compound for such activity.

Fermenation Products of β-Mannanase Producing Bacteria Inhibit Selected Poultry Borne Pathogens.

Aim: The study evaluated the inhibitory effect of fermentation products of β-mannanaseproducing bacteria on selected poultry borne pathogens. Study Design: The first experiment, bacterial isolates previously confirmed positive for mannanase by plate assay technique were further screened for mannanase production in submerged state fermentation. In the second experiment, inhibitory effect of fermentation products of mannanase-producing bacteria on selected poultry pathogens was evaluated. Place and Duration of Study: Microbiology Research Laboratory, Federal University of Technology, Akure Nigeria between September 2011 and March 2012. Methodology: Bacterial isolates from agricultural wastes previously confirmed positive for mannanase activity by plate assay were further screened for their potential performance under submerged state fermentation and enzyme activity determined by dinitrosalicylic acid method. The inhibitory action of β-mannanase-producing bacteria was determined by supplementation of supernatant and plating method. Results: Isolate 1A showed highest mannanase activity (13.430 U/ml), displayed broad inhibition to selected poultry borne pathogens; Klebsiella oxytoca, Shigella alkalescens, Escherichia coli, Salmonella typhii, Staphylococcus aureus and Streptococcus sp. Apart from isolate 1A, fermentation products of other isolates generated from the mannolytic action of β-mannanase on mannan containing substrate displayed different percentage inhibition on selected poultry borne pathogens. Conclusion: The results suggested that fermentation products from β-mannanaseproducing bacteria might possess antibacterial properties which could be applied in poultry farms.

Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

<p><b>OBJECTIVE</b>To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis.</p><p><b>METHODS</b>Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts.</p><p><b>RESULTS</b>Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth.</p><p><b>CONCLUSIONS</b>The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.</p>

Antioxidant potential of phenolic extracts of Mimusops elengi

Objective:To evaluate the antioxidant potential of the phenolic extracts of Mimusops elengi (M. elengi) L. (Sapotaceae). Methods:The extract of stem bark and seeds of M. elengi were prepared in methanol and acetone:water (7:3). The acetone: water was further partitioned with ethyl acetate and n-butanol. Antioxidant activity of the extracts and partitioned fractions of M. elengi was evaluated in terms of radical scavenging potential (DPPH), inhibition of lipid peroxidation [ferric thiocyanate (FTC)], and total antioxidant activity (phosphomolybdate method). Total phenolics content were calculated using Folin-Ciocalteu reagent. Results:The stem bark extract partitioned with ethyl acetate exhibited highest amount of total phenols (98.0 mg GAE/g dry weight), among all other extracts, with 92.0%DPPH radical scavenging activity at concentration of 0.5 mg/mL, while methanol extract (stem bark) had maximum inhibition of lipid peroxidation (62.0%) and total antioxidant activity (771.0 mg/g GAE/g). A positive correlation occurred between total phenols and radical scavenging activity (R2= 0.922 9) and total antioxidant activity (R2= 0.945 1). Conclusions: Our study suggested that antioxidant activity of stembark extract of M. elengi is due the presence of phenolic compounds. Furthermore, the bark extract is a valuable source of natural antioxidants.

Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

Objective: To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods:Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results:Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions: The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.