The preventive effects of hydroxychalcone derivatives on
ulcer formation induced by severe necrotizing agents such as 60%
ethanol in 150 mM HCl (HCl-
ethanol) and 0.2 N NaOH in rats were examined. Among the compounds tested,
2',4'-dihydroxychalcone gave the strongest activity in both experimental models and protected the gastric mucosa from the insult of either necrotizing agent at oral doses ranging from 1 to 10 mg/kg, as evidenced by a dose-related reduction in the
ulcer index. The mucosal protective activity of
2',4'-dihydroxychalcone was not affected by pretreatment with
indomethacin (5 mg/kg, s.c.). To investigate the detailed mechanism of the mucosal protective action of
2',4'-dihydroxychalcone, its inhibitory effects on the decrease in the
hexosamine content from the gastric mucus induced by HCl-
ethanol were studied by using it in combination with a
dye,
Alcian blue. As a result,
2',4'-dihydroxychalcone at an oral dose of 10 mg/kg inhibited the decrease in the
dye-recovery from the gastric mucus induced by HCl-
ethanol.
PGE2 at an oral dose of 0.1 mg/kg exhibited a similar action. These results established that
2',4'-dihydroxychalcone is a potent cytoprotective agent similar to
PGE2 effectively preventing
gastric ulcer formation induced by strong necrotizing agents and seems to suggest that this compound protects the stomach against its own peptic secretions by reinforcement of gastric resistances. In fact,
2',4'-dihydroxychalcone prevented
ulcer formation induced by water-immersion stress in rats and also showed a marked enhancement of the healing of
acetic acid-induced
gastric ulcers in rats.