Study on effect of anti-diarrheal medicinal plants on enteropathogenic Escherichia coli induced interleukin-8 secretion by intestinal epithelial cells

Diarrhea is a major health concern in developing countries with enteropathogenic Escherichia coli (EPEC) being a leading cause of infantile diarrhea. Much of the pathology of EPEC infection is due to the inflammatory responses of infected intestinal epithelium through secretion of pro-inflammatory cytoki - nes such as interleukin (IL)-8. With medicinal plants gaining popularity as prospective antidiarrheal agents, we aimed to evaluate the effect of anti-diarrheal medicinal plants on secretion of IL-8 by epithelial cells in response to EPEC infection. The effect of the decoctions of four anti-diarrheal medicinal plants viz. Aegle marmelos, Cyperus rotundus, Psidium guajava and Zingiber officinale was studied on secretion of IL-8 by a human colon adenocarcinoma cell line, HT-29 infected with E. coli E2348/69. Two protocols were used viz. pre-incubation and post-incubation. The data obtained demonstrated that out of the four plants used, only P. guajava decreased secretion of IL-8 in the post-incubation protocol although in the pre-incubation protocol an increase was observed. A similar increase was seen with C. rotundus in the preincubation protocol. No effect on IL-8 secretion was observed with A. marmelos and Z. officinale in both protocols and with C. rotundus in the post-incubation protocol. The post-incubation protocol, in terms of clinical relevance, indicates the effect of the plant decoctions when used as treatment. Hence P. guajava may be effective in controlling the acute inflammatory response of the intestinal epithelial cells in response to EPEC infection.