Protective Effects of Cinnamic Acid Derivatives on Gastric Lesion

P-methoxycinnamic acid and 3,4,5-trimethoxycinnamic acid are the compounds found in Polygalae Radix, the root of Polygala tenuifolia Willdenow, and have been reported to have hepatoprotective and anti-neurodegenerative effects. On the other hand, there are no reports of their effects on gastric lesions. This study examined the inhibitory effects of cinnamic acids, including p-methoxycinnamic acid, 3,4,5-trimethoxycinnamic acid, and 8 compounds (cinnamic acid, 2-(trifluoromethyl) cinnamic acid, 3-(trifluoromethyl) cinnamic acid, trans-4-(trifluoromethyl) cinnamic acid, 4-(dimethylamino) cinnamic acid, 3,4-(methylenedioxy) cinnamic acid and 3,4-dihydroxycinnamic acid), which were selected based on their presence in medicinal herbs and molecular weight, against gastric lesions. Animal models were used to confirm the protective effects on acute gastritis caused by the administration of HCl/EtOH. Gastric acid inhibition was examined by an acid-neutralizing test and the proton pump (H⁺/K⁺-ATPase) inhibiting activity. In addition, antioxidant tests were performed and the gastric emptying rate was determined. The results showed that cinnamic acid, p-methoxycinnamic acid, and 3,4,5-trimethoxycinnamic acid had an inhibitory effect on gastric lesions.

Protective Effect of Liriodendrin Isolated from Kalopanax pictus against Gastric Injury

In this study, we investigated the inhibitory activities on gastritis and gastric ulcer using liriodendrin which is a constituent isolated from Kalopanax pictus. To elucidate its abilities to prevent gastric injury, we measured the quantity of prostaglandin E2 (PGE2) as the protective factor, and we assessed inhibition of activities related to excessive gastric acid be notorious for aggressive factor and inhibition of Helicobacter pylori (H. pylori) colonization known as a cause of chronic gastritis, gastric ulcer, and gastric cancer. Liriodendrin exhibited higher PGE2 level than rebamipide used as a positive control group at the dose of 500 microM. It was also exhibited acid-neutralizing capacity (10.3%) and H+/K+-ATPase inhibition of 42.6% (500 microM). In pylorus-ligated rats, liriodendrin showed lower volume of gastric juice (4.38 +/- 2.14 ml), slightly higher pH (1.53 +/- 0.41), and smaller total acid output (0.47 +/- 0.3 mEq/4 hrs) than the control group. Furthermore liriodendrin inhibited colonization of H. pylori effectively. In vivo test, liriodendrin significantly inhibited both of HCl/EtOH-induced gastritis (46.9 %) and indomethacin-induced gastric ulcer (46.1%). From these results, we suggest that liriodendrin could be utilized for the treatment and/or protection of gastritis and gastric ulcer.