Browsing by Author "Agunbiade, Kehinde Adedapo"

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    Studies on antimicrobial effects of methanolic extract of Cymbopogon citratus and Zingiber officinale on some bacterial Isolates.
    (Microbiology,Obafemi Awolowo University, 2014) Agunbiade, Kehinde Adedapo
    This study investigated the individual and combined antimicrobial effects of methanolic extract of Cymbopogon citratus and Zingiber officinale on some test bacteria. This was with a view to evaluating and confirming their antimicrobial activity, determining their minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) and evaluatingtheir combined effects. Fresh leaves of C. citratusand rhizomes of Z. officinalewere separately washed, air-dried under shadeand ground into powder. The powdered plant materials were extractedwith methanol;concentrated in vacuo using a rotary evaporator and dried using silica gel inside dessicator. The extracts were screened for their phytochemical groups.Their antimicrobial activity against Gram-positiveand Gram-negative bacteria was evaluated by agar well diffusion method.The extracts were partitioned using different organic solventsin order of polarity starting from n-hexane, chloroform, ethyl acetate and n-butanol. The MIC and MBC of the extracts and their respective fractions were determined. The combined effects of the extracts were evaluated and their antimicrobial activity was compared with standard antibiotics – streptomycin and ciprofloxacin. The rate of killing of the active fractions was determined on selected Gram-positive and Gram-negative bacteria following standard procedures. The primary methanolic extracts of both plantsand subsequent chloroform and ethyl acetate fractions of C. citratus; chloroform and n-hexane fractions of Z. officinale and their combined chloroform fractions exhibited varying degree of antibacterial activity against 14 out of the 15 bacteria tested. These included both Gram-positive and Gram-negative bacteria indicating broad-spectrum antibacterial effects of the extracts. Only Pseudomonas aeruginosa was not susceptible to the effects of the extracts. Most of the MIC values were the same as the