Jiraporn Kuljiraruk. Effect of Holarrhena Antidysenterica extract on the growth of local thai isolate of entamoeba histolytica. Master's Degree(Tropical Medicine). Mahidol University. : Mahidol University, 2007.
Effect of Holarrhena Antidysenterica extract on the growth of local thai isolate of entamoeba histolytica
Abstract:
The objective of this study was to analyze the effects of Holarrhena antidysenterica extract to
the growth of Entamoeba histolytica (S strain) and E. moshkovskii (LA strain) and 8 pathogenic bacteria
in vitro. Crude extract was crunched and homogenously dissolved in distilled water. Water extract of
herbal plant was sterilized by membrane filtering and then transferred to the aqueous phase of biphasic
media which contained about 105 amoeba cells per ml. After 24 hours of exposure, living amoebae
were counted by dye exclusion with Tryphan blue stain. Comparative experiments consisted of the
observation of viable trophozites in negative control, without additional herbal extract and in positive
control, with addition of metronidazole. The percentage of survival was calculated from the number of
dead and viable cells. The results showed that diluted herbal aqueous extract of H. antidysenterica at a
concentration of 15 mg/ml could completely kill E. histolytica (S strain) trophozoites, while E.
moshkovskii (LA strain) trophozoites were completely killed by using concentration of 30 mg/ml.
Metronidazole used as positive control, could kill both strains of Entamoeba trophozoites at a
concentration of 50μg/ml.
Moreover, H. antidysenterica extract was tested along with 8 pathogenic bacteria by the agar
diffusion method. The bacterial species that produce clear inhibition zones were subjected to determine
the mechanism of growth inhibition by plate counting method in media agar with and without herbal
extract. Herbal aqueous extract of H. antidysenterica was not able to inhibit the growth of Escherichia
coli and Pseudomonas aeruginosa. In contrast, it was able to inhibit the growth of Plesiomonas
shigelloides, Shigella flexneri and Vibrio cholerae via the bactericidal mechanism. Aeromonas
hydrophila, Salmonella cholerasuis and Staphylococcus aureus were inhibited by herbal aqueous
extract via the transient bacteriostatic mechanism.