Abstract
Buffering of stomach acid by antacids is a well-established symptomatic therapy for heartburn. In addition, preparations from prickly pear (Opuntia ficus-indica) have been shown to reduce tissue damage in experimental gastritis models and to attenuate gastrointestinal discomfort in patients. Both active principles have been included in a fixed-combination product for symptomatic treatment of heartburn containing carbonate antacids (CaCO3 and MgCO3) and an extract from Opuntia ficus-indica cladodes. The aim of the study was to characterize the acid neutralization and esophageal cell protective activities of the product and its individual active ingredients in a set of in vitro assays. Acid neutralization was assessed in a simulated stomach model. Protective activity of individual constituents and in combination was analyzed in an esophageal cell line (COLO-680 N) exposed to low pH and deoxycholic acid to simulate acidic and non-acidic reflux challenge. The combination product protected cells against low pH mediated cytotoxicity via acid neutralization by carbonates. Opuntia extract itself and the combination product attenuated bile acid-induced cell irritation as measured by reduced release of proinflammatory interleukin-6 and -8. In conclusion, addition of Opuntia extract to a mineral antacid provides dual protection against acidic and non-acidic simulated reflux challenge.