Kazeem Adekunle Alayande1, Carolina H Pohl2, Anofi Omotayo Tom Ashafa3. 1. Phytomedicine and Phytopharmacology Research Group, Department of Plant Sciences, University of the Free State, Qwaqwa Campus, P/Bag X13, Phuthaditjhaba 9866, South Africa; Department of Microbial, Biochemical & Food Biotechnology, University of the Free State, P.O. Box 339/205 Nelson Mandela Drive, 9301 Bloemfontein, South Africa. Electronic address: jkadekunle2@gmail.com. 2. Department of Microbial, Biochemical & Food Biotechnology, University of the Free State, P.O. Box 339/205 Nelson Mandela Drive, 9301 Bloemfontein, South Africa. 3. Phytomedicine and Phytopharmacology Research Group, Department of Plant Sciences, University of the Free State, Qwaqwa Campus, P/Bag X13, Phuthaditjhaba 9866, South Africa.
Abstract
OBJECTIVE: To evaluate antimicrobial potential of the fractions partitioned from Euclea crispa leaf extract and determination of their impact on cell membrane disruption. METHODS: Antimicrobial potentials were evaluated via susceptibility test, determination of minimum inhibitory concentrations (MICs) and time-kill kinetics of the potent fractions. Degree of membrane disruption was determined by the amount of proteins and nucleotides released from within the cells and SEM images of the membrane after 120 min of treatment. RESULTS: The largest inhibition zone (25.5 ± 0.50 mm) was obtained by ethylacetate fraction against Aeromonas hydrophilla at 10 mg/mL. The lowest MIC (0.16 mg/mL) was exhibited by n-butanol and ethylacetate fractions against test bacteria while all fractions exhibited MIC values between 0.31 and 1.25 mg/mL against susceptible yeast. n-Butanol fraction achieved absolute mortality against Bacillus pumulis (B. pumulis) and Klebsiella pneumoniae (K. pneumoniae) after 90 and 120 min contact time respectively at 1 × MIC. Total mortality also achieved by n-hexane fraction against B. pumulis and K. pneumoniae after 90 and 120 min respectively at 2 × MIC. Ethylacetate fraction achieved absolute mortality against both bacteria after 120 min at 2 × MIC. n-Hexane fraction achieved total mortality against Candida albicans after 120 min at 1 × MIC. Maximum amount of proteins (0.566 μg/mL) was released from K. pneumoniae by n-butanol fraction at 2 × MIC after 120 min of treatment while the maximum amount of nucleotides released (4.575 μg) was from B. pumulis by n-hexane fraction under similar condition. CONCLUSION: This study suggests the leaf of Euclea crispa a source of bioactive compound with membrane attack as one of the mechanisms of its biocidal action.
OBJECTIVE: To evaluate antimicrobial potential of the fractions partitioned from Euclea crispa leaf extract and determination of their impact on cell membrane disruption. METHODS: Antimicrobial potentials were evaluated via susceptibility test, determination of minimum inhibitory concentrations (MICs) and time-kill kinetics of the potent fractions. Degree of membrane disruption was determined by the amount of proteins and nucleotides released from within the cells and SEM images of the membrane after 120 min of treatment. RESULTS: The largest inhibition zone (25.5 ± 0.50 mm) was obtained by ethylacetate fraction against Aeromonas hydrophilla at 10 mg/mL. The lowest MIC (0.16 mg/mL) was exhibited by n-butanol and ethylacetate fractions against test bacteria while all fractions exhibited MIC values between 0.31 and 1.25 mg/mL against susceptible yeast. n-Butanol fraction achieved absolute mortality against Bacillus pumulis (B. pumulis) and Klebsiella pneumoniae (K. pneumoniae) after 90 and 120 min contact time respectively at 1 × MIC. Total mortality also achieved by n-hexane fraction against B. pumulis and K. pneumoniae after 90 and 120 min respectively at 2 × MIC. Ethylacetate fraction achieved absolute mortality against both bacteria after 120 min at 2 × MIC. n-Hexane fraction achieved total mortality against Candida albicans after 120 min at 1 × MIC. Maximum amount of proteins (0.566 μg/mL) was released from K. pneumoniae by n-butanol fraction at 2 × MIC after 120 min of treatment while the maximum amount of nucleotides released (4.575 μg) was from B. pumulis by n-hexane fraction under similar condition. CONCLUSION: This study suggests the leaf of Euclea crispa a source of bioactive compound with membrane attack as one of the mechanisms of its biocidal action.