Gastroprotective and gastric motility benefits of AD-lico/Healthy Gut™ Glycyrrhiza inflata extract

Abstract

The aim of this study was to evaluate in vivo both the anti-Helicobacter and the gastric-relaxing effects of AD-lico/Healthy Gut™ in rat models. AD-lico/Healthy Gut™ is a specially prepared commercial formulation of Glycyrrhiza inflata extract that is under clinical development for indications of gastrointestinal disease and inflammatory bowel disease. In the current study, the oral administration of AD-lico/Healthy Gut™ significantly reduced mucosal damage from Helicobacter pylori in rats and decreased the expression of the inflammatory markers iNOS and COX-2 in the test cells. AD-lico/Healthy Gut™ also reduced mucosal damage caused by water immersion stress in rats. The accelerated gastric emptying in normal rats was also seen with AD-lico/Healthy Gut™, providing relief in gastric relaxation in the test animals. The special formulation of AD-lico/Healthy Gut™ with reduced levels of component glycyrrhizin also has benefits in minimizing the potential side effects attributed to glycyrrhizin seen with similar Glycyrrhiza extracts in terms of induction of hypokalemia and muscle weakness. The preparation has a relatively high phenolic compound content relative to other methods of preparation and is indicative of lower glycyrrhizin levels. These results suggest that AD-lico/Healthy Gut™ may provide the necessary relief from a number of stomach discomfort issues faced by a large population of people.

Keywords: Helicobacter pylori; Licorice extract; stomach comfort.

Figure 1.

Improvement of dose-dependent mucosal damage caused by H. pylori in rats. The variables were normal control animals, H. pylori treated animals, H. pylori plus AD-lico/Healthy Gut™ 25 mg/kg, H. pylori plus AD-lico/Healthy Gut™ 50 mg/kg, and H. pylori plus AD-lico/Healthy Gut™ 100 mg/kg. The pathologic scores from the tissue slides were calculated and plotted. The error bars are SD values from five animals per group. This is a representative of two experiments. In the plot, relative to H. pylori control, not significant (ns), *p < .05, and **p < .01 were the designations of significance.

Figure 2.

AD-lico/Healthy Gut™ downregulated H. pylori-induced iNOS and COX-2 expression in AGS cells. (A) Normal control; (B) negative control; (C) AD-lico/Healthy Gut™ 25 mg/kg; (D) AD-lico/Healthy Gut™ 50 mg/kg; (E) AD-lico/Healthy Gut™ 100 mg/kg. Western blots of the treated cell lysates were probed for iNOS, COX-2 and actin.

Figure 3.

Improvement of mucosal damage caused by water immersion stress in rats with AD-lico/Healthy Gut™. (A) Normal control; (B) negative control; (C) AD-lico/Healthy Gut™ 25 mg/kg; (D) SWG 50 mg/kg. AD-lico/Healthy Gut™ showed better protective effects when compared with an approved functional food (SWG) (Korea) to improve stomach function. After the water/restraint protocol, the animals were sacrificed; their stomachs were then removed, and dissected along the greater curvature of the stomach. Mucosal damage was assessed macroscopically. Representative specimens are shown.

Figure 4.

Improvement of GE in rats. G1, Normal control; G2, negative control; G3, mosapride 10 mg/kg; G4, AD-lico/Healthy Gut™ 100 mg/kg. The rats were fasted and then given measured semi-solid meals by gavages at 60 min following drug administration. After 30 min, animals were sacrificed, and their stomachs and contents were weighed and photographed. Five (5) samples per group are shown (A), along with quantitated GE rates (B). ***p < .001 and *p < .05 denote significance compared with G2 negative control.