Modulation of a Cellular Transport Activity by Capsicum Extracts

Background: Microbes are often internalized by host cells as part of the infection process. Compounds that can modulate such uptake may have applications in prevention of infectious diseases. Capsaicinoids, capsinoids, and other Capsicum sp. components are reported to target several pathological processes including microbial infections. Capsicum phytochemicals can alter biophysical properties of animal cell membranes, and such effects may contribute to putative therapeutic effects. Method: Standardized Capsicum (Cayenne pepper) extracts were analyzed for their capacity to modulate membrane transport. Transferrin (Tf), a well-characterized ligand for studies of receptor-mediated endocytosis, was analyzed in a mammalian epithelial cell line. Results: The extracts inhibited transport, IC50 84.2 +/- 4.8 GAE units (p < 0.05 relative to controls). At similar Capsicum polyphenol concentrations, no statistically significant effects (p >> 0.05) were observed for Tf binding or recycling. Conclusion: The results indicate a novel bioactivity of Capsicum, and provide a possible functional mechanism that complements changes in membrane structure and reported anti-infection activities. Keywords: Capsicum, cayenne pepper, capsaicinoids, capsinoids, endocytosis, cell transport.