Gastroprotective Effects of Glutinous Rice Extract against Ethanol-, Indomethacin-, and Stress-induced Ulcers in Rats / 전남의대학술지

This study was designed to evaluate the efficacy of an orally administered aqueous extract of glutinous rice (GRE) to protect against acute gastric mucosal lesions induced by ethanol, indomethacin, and water immersion restraint stress in rats and to characterize the active substances responsible for the protection. GRE was shown to dose-dependently prevent the gastric lesions induced by the above ulcerogenic treatments at doses of 30 to 300 mg/kg. GRE treatment increased the gastric mucin content and partially blocked the ethanol-induced depletion of the gastric mucus layer. Also, it increased the nonprotein sulfhydryl concentration in the gastric mucosa. The gastroprotective action of GRE was markedly enhanced by co-treatment with 4-8 mg/kg tea extracts. The activity of GRE was completely lost by heat treatment at 80degrees C for 3 min or treatment with 0.01% pepsin at 37degrees C for 1 h. Protein extraction studies indicated that prolamins are involved in the gastroprotective activity of GRE. Our results suggest that glutinous rice proteins are useful for the prevention and treatment of gastritis and peptic ulcer.

Gastroprotective Effects of Glutinous Rice Extract against Ethanol-, Indomethacin-, and Stress-induced Ulcers in Rats / 전남의대학술지

This study was designed to evaluate the efficacy of an orally administered aqueous extract of glutinous rice (GRE) to protect against acute gastric mucosal lesions induced by ethanol, indomethacin, and water immersion restraint stress in rats and to characterize the active substances responsible for the protection. GRE was shown to dose-dependently prevent the gastric lesions induced by the above ulcerogenic treatments at doses of 30 to 300 mg/kg. GRE treatment increased the gastric mucin content and partially blocked the ethanol-induced depletion of the gastric mucus layer. Also, it increased the nonprotein sulfhydryl concentration in the gastric mucosa. The gastroprotective action of GRE was markedly enhanced by co-treatment with 4-8 mg/kg tea extracts. The activity of GRE was completely lost by heat treatment at 80degrees C for 3 min or treatment with 0.01% pepsin at 37degrees C for 1 h. Protein extraction studies indicated that prolamins are involved in the gastroprotective activity of GRE. Our results suggest that glutinous rice proteins are useful for the prevention and treatment of gastritis and peptic ulcer.

Hemin inhibits lipid peroxidation induced by ascorbate/FeSO4 and 2,2'-azobis-2-amidino-propane hydrochloride (ABAP)

Hemin blocked lipid peroxidations induced by either ascorbate/FeSO4, a metal-catalyzed oxidation system, or 2,2'-azobis-2-amidino-propane hydrochloride (ABAP) which produces peroxy radicals at constant rates. Hemin at very low micromolar concentrations strongly inhibited the ascorbate/FeSO4-induced peroxidation of rat liver phopholipids, soybean phosphatidylcholine and arachidonic acid, and this inhibition was also evident with the use of ABAP, although much higher concentrations of hemin were required than those for the inhibition of ascorbate/FeSO4-induced lipid peroxidation. However, hemoproteins such as hemoglobin, myoglobin and cytochrome C did not show any significant effect on this lipid peroxidation. Hemopexin and albumin abolished the inhibitory action of hemin. During incubation with ascorbate/FeSO4 or ABAP, hemin underwent a change in its absorption spectrum, resulting in a progressive decrease in the peak height of the characteristic absorption band at 385 nm. The above results suggest that hemin may act as an important antioxidant in vivo, protecting lipids from the peroxidative damage.