Diarrhea is a common cause of death in developing countries and the second most common cause of infant deaths worldwide [1]. Since the conventional diarrhea therapies such as antibiotics are known to produce various adverse effects and their availability in developing countries is limited [2], the plant-derived medicines are considered as possible alternative therapy of diarrhea treatment [3]. Therefore, the objective of this research was to investigate in vitro growth-inhibitory effect of thirteen plant compounds and their derivatives.
The minimum inhibitory concentrations (MICs) of aloe emodin, antrachinon, capsaicin, curcumin, naringenin, norhydrogenic acid, pterostilbene, zinc pyrithione, resveratrol, rhein, rutin, sanguinarine and trihydroxyisloflavone were determined by the broth microdilution method [4] against diarrhea causing bacteria Enterococcus faecalis, Escherichia coli, Listeria monocytogenes and Salmonella enteritidis.
The best results were obtained for zinc pyrithione with the MIC 4 µg/mL followed by sanguinarine with MICs ranking from 16 to 32µg/mL. Moderate antibacterial effect has been observed for rhein and pterostilbene on Enterococcus faecalis with the MICs 32 and 64 µg/mL, respectively. In contrast to the previously reported growth-inhibitory effect of sanguinarine on Enterococcus faecalis [5], according to our best knowledge, there are no reports on antibacterial effect of zinc pyrithione, a compound used in treating dandruff and seborrhoeic dermatitis [6], on representatives of diarrhea causing microorganisms.