Browsing by Author "Zakariyah, R.F"

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    Antibacterial evaluation of extract of seed of kernel and leaf of Moringa oleifera against bacteria from raw cow milk
    (Nigerian Journal of Microbiology, 2016) Zakariyah, R.F; Sani, A; Odebisi-Omokanye, M.B.; Ahmed, R.N.
    Abstract: Moringa oleiferahas been found very useful in a lot of health related problems owing to its medicinal components and values, these has led to research on its antibacterial activity against food borne pathogens. Aqueous and acetone extracts of Moringa oleifera seed kernel and leaf were evaluated for antibacterial activity against Bacillus cereus, Staphylococcus aureus and Escherichia coli isolated from raw cow milk. The antibacterial assay was carried out at concentrations of 250, 125, 62.5 and 31.25mg/ml using modified agar well diffusion method. Aqueous extract inhibited the growth of test isolates at varying degrees. Aqueous extract of seed kernel was highly inhibitory on Staphylococcus aureus with a zone of inhibition (23.33±1.20mm) at concentration of 250mg/ml. Minimum Inhibitory Concentration showed that both extracts inhibited the growth of Bacillus cereus, Staphylococcus aureus and Escherichia coli at concentrations ranging from 125 to 21.25mg/ml. The antibacterial effect of standard antibiotics was performed and it was observed that Gentamycin inhibited growth of the three test isolates. Preliminary phytochemical screening revealed the presence of alkaloids, flavonoids, steroids, saponin, tannin, phenols, glycosides and carbohydrates compound in the extracts. From the present study, Moringa oleifera seed kernel and leaf can be a promising source of phytochemical components and further studies is therefore recommended. Key words: Food-borne pathogens, Minimum Inhibitory Concentration, Moringa oleifera, Phytochemical screening,
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    Green synthesis and antibacterial activity of silver nanoparticles from extract of leaves of Croton zambesicus
    (Nigerian Journal of Microbiology, 2016) Ahmed, R,N; Sani, A; Oluwo, O.N; Sule, I.O; Zakariyah, R.F
    Abstract: Silver nanoparticles (AgNPs) was synthesized using a combination of aqueous extract of Croton zambesicus and silver nitrate (AgNO3) solution to obtain various concentrations of 100mg/ml, 200mg/ml, 300mg/ml and 400mg/ml at 10mM. Characterization of the synthesized silver nanoparticle was done by UV-visible spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). Antimicrobial activity against four bacterial isolates was determined by standard method of agar-well diffusion assay. The activity of two standard antibiotics was compared with the AgNPs of C. zambesicus using the disc diffusion method. The Minimum Inhibitory Concentration (MIC) was achieved using microbroth dilution technique. Test tubes that showed low turbidity in the MIC assays were reinoculated on sterile agar plates and this was taken as Minimum Inhibitory Concentration (MBC). The presence of phytochemical constituent was examined using standard methods. The total yield of the AgNPs of the plant extract was 10.94g. The characterization by UV-visible revealed that at a wavelength of 429.0nm the particle has peak absorbance of 2.003, while the FTIR showed the presence of five (5) functional groupsE. coli demonstrated reduction in activity as concentration increased with zone diameter of 24mm at 100mg/ml and 10mm at 400mg/ml. The analysis of MIC and MBC revealed inhibitory and bactericidal effects at the same concentration of 30mg/ml. The mode of action of the AgNPs at 100mg/ml showed a total cell lysis of all test isolates. Following the results of the phytochemical analysis, the presence of six phytochemicals were observed. It is evident from this study that AgNPs synthesized from extract of leaf of C. zambesicus is a very effective antibacterial agent that can compare favourably with conventional antibiotics, hence considering it as an alternative in the elimination of the tested isolates and infections caused by them. Keywords: Croton Zambesicus, agar diffusion, FTIR, UV- Vis, Antibacterial