Medicinal Plant Extracts as Anti-Escherichia coli O157:H7 Agents and Their Effects on Bacterial Cell Aggregation

• Published in: Journal of food protection 2006-10, Vol.69 (10), p.2336-3241
• Main Authors: Voravuthikunchai, S.P, Limsuwan, S
• Format: Article
• Language: English
• Subjects: Acacia; Acacia - chemistry; Acacia catechu; Andrographis paniculata; Anti-Bacterial Agents - pharmacology; antibacterial properties; bacterial contamination; Colony Count, Microbial - methods; Dose-Response Relationship, Drug; Escherichia coli; Escherichia coli Infections - drug therapy; Escherichia coli O157 - drug effects; Escherichia coli O157 - growth & development; Escherichia coli O157:H7; essential oils; ethanol; Fabaceae - chemistry; food contamination; food pathogens; Humans; Hydrophobic and Hydrophilic Interactions; hydrophobicity; Lythraceae - chemistry; medicinal plants; Microbial Sensitivity Tests; minimum inhibitory concentration; Peltophorum; Peltophorum pterocarpum; Phytotherapy; plant extracts; Plant Extracts - pharmacology; Plants, Medicinal - chemistry; Pluchia indica; Punica granatum; Quercus; Quercus - chemistry; Quercus infectoria; supercritical fluid extraction; Tamarindus indica; traditional medicine; Walsura robusta
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-69.10.2336

Ethanolic extracts of eight Thai medicinal plants (representing five families) that are used as traditional remedies for treating diarrhea were examined with a salt aggregation test for their ability to modulate cell surface hydrophobicity of enterohemorrhagic Escherichia coli strains, including E. coli O157:H7. Four of these medicinal plants, Acacia catechu, Peltophorum pterocarpum, Punica granatum, and Quercus infectoria, have high bacteriostatic and bactericidal activities. The ethanolic extract of Q. infectoria was the most effective against all strains of E. coli, with MICs of 0.12 to 0.98 mg/ml and MBCs of 0.98 to 3.91 mg/ml. The ethanolic extract of P. granatum had MICs of 0.49 to 1.95 mg/ml and MBCs of 1.95 to 3.91 mg/ml. Ethanolic extracts of Q. infectoria, P. pterocarpum, and P. granatum were among the most effective extracts against the two strains of E. coli O157:H7. The other four plants, Andrographis paniculata, Pluchia indica, Tamarindus indica, and Walsura robusta, did not have high bacteriostatic and bactericidal activities but were able to affect hydrophobicity characteristics on their outermost surface. All plants except Q. infectoria had some ability to increase cell surface hydrophobicity. There appears to be no correlation between antibacterial activity and cell aggregative properties.