The investigation of antimicrobial impact of Thai medicinal plant extracts against Escherichia coli strains

Abstract number: 1134_01_71

Voravuthikunchai S.P., Limsuwan S., Wanmanee S.


The effect of medicinal plant extracts on cell surface hydrophobicity has been claimed to be one important antimicrobial mechanism. The aim of our study was to closely investigate the effect of aqueous extracts of medicinal plants, widely used in Thai traditional medicine for the treatment of diarrhoea, on Escherichia coli surface properties and to correlate this mechanism with their antimicrobial activity.


The effects of aqueous and ethanolic extracts of ten medicinal plant species including Punica granatum Acacia catechu, Andrographis paniculata, Holarrhena antidysenterica, Peltophorum pterocarpum, Piper sarmentosum, Pluchea indica, Psidium guajava, Punica granatum, Tamarindus indica, and Walsura robusta were used against 15 different strains of E. coli. Salt aggregation test to study their cell surface hydrophobicity, agar diffusion assay, and agar microdilution method for detection of antimicrobial activity were studied.


Acacia catechu and Punica granatum increased hydrophobicity of all bacterial strains tested 3 strains of E. coli O157: H7 isolated from outbreak in Japan 1997, E. coli O26: H11, E. coli O111: NM, E. coli O22, 3 strains of E. coli O157 O157: H7 isolated from food, 5 strains of E. coli isolated from bovine, and E. coli ATCC 25922. The hydrophobicity of bacterial strains increased depending on the concentration of medicinal plants tested. There was no correlation between aggregation property and antimicrobial activity.


The activity of medicinal plants on hydrophobicity of the E. coli cells showed no correlaton with the antibacterial activity.


This work was supported by a fund from Thailand-Tropical Diseases Research Programme. National Center for Genetic Engineering and Biotechnology, Fiscal year 2004.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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