2008 年 54 巻 1 号 p. 112-117
Molecules with bi-functional activities are preferred targets in drug discovery research today. In this study, a possible dual role (anti-inflammatory and anti-bacterial activity) of a plant extract has been discussed. As an initiative, the extract is found to suppress inflammation caused by endotoxin release from an enteric pathogen. Enteropathogenic Escherichia coli (E. coli) (EPEC O127:H6) causes persistent diarrhea and continues to be a major health problem among infants in developing countries. Host inflammatory response during EPEC infection is weak when compared to infections caused by other enteric pathogens. This is due to the suppression of intestinal inflammatory response by type III secreted proteins of EPEC during infection process. The weak inflammatory response is thus possibly due to disruption of tight junctions, which in turn facilitate recruitment of macrophages from the underlying lamina propria or shedding of bacterial products like lipopolysaccharide (LPS) during antibiotic mediated bacterial lysis. Since intestinal cells are non-responsive to LPS, the inflammatory response would be elicited by the intestinal macrophages present at the site of infection. Apart from commercial LPS from E. coli O111:B4, LPS was isolated from EPEC and used for inducing inflammatory markers like TNFα, IL-1β, IL-8 and TLR4 in J774 A.1 murine macrophage like cells to make this study clinically relevant. Alpinia officinarum is a traditional, perennial herb used widely in China and India for treating arthritis and gastrointestinal disorders. The ethyl acetate extract of Alpinia officinarum effectively suppressed EPEC LPS induced inflammatory response thereby exhibiting potential in a clinical scenario, wherein diarrhea induced by EPEC or products of its lysis is either a consequence of macrophage induced inflammation or antibiotic treatment or due to a potential, yet to be analyzed, anti-bacterial activity of Alpinia officinarum extract against EPEC.
