Stem Bark Extract and Fraction of Persea americana (Mill.) Exhibits Bactericidal Activities against Strains of Bacillus cereus Associated with Food Poisoning

Molecules

David A. Akinpelu²  Olayinka A. Aiyegoro³  Oluseun F. Akinpelu¹  Anthony I. Okoh² 

[1]Department of Biological Science, Faculty of Agriculture and Technology, North West University, Mafikeng Campus, Mmabatho 2735, South Africa

[2] E-Mail:

[3]SA-MRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa

[4] E-Mails:

[5]Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa

关键词: Persea americana;    Bacillus cereus;    antimicrobial activity;    killing rate;    protein leakage;    potassium ion leakage;    minimum inhibitory concentration;   

DOI  :  10.3390/molecules20010416

来源: mdpi

【 摘 要 】

The study investigates the in vitro antibacterial potentials of stem bark extracts of Persea americana on strains of Bacillus cereus implicated in food poisoning. The crude stem bark extracts and butanolic fraction at a concentration of 25 mg/mL and 10 mg/mL, respectively, exhibited antibacterial activities against test isolates. The zones of inhibition exhibited by the crude extract and the fraction ranged between 10 mm and 26 mm, while the minimum inhibitory concentration values ranged between 0.78 and 5.00 mg/mL. The minimum bactericidal concentrations ranged between 3.12 mg/mL–12.5 mg/mL and 1.25–10 mg/mL for the extract and the fraction, respectively. The butanolic fraction killed 91.49% of the test isolates at a concentration of 2× MIC after 60 min of contact time, while a 100% killing was achieved after the test bacterial cells were exposed to the butanolic fraction at a concentration of 3× MIC after 90 min contact time. Intracellular protein and potassium ion leaked out of the test bacterial cells when exposed to certain concentrations of the fraction; this is an indication of bacterial cell wall disruptions by the extract’s butanolic fraction and, thus, caused a biocidal effect on the cells, as evident in the killing rate test results.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.