Effects and possible mechanisms of Alpinia officinarum ethanol extract on indomethacin-induced gastric injury in rats

Context: Alpinia officinarum Hance (Zingiberoside) has a long history in treating gastrointestinal diseases, but its mechanisms of action are not yet known. Objective: To investigate the effects and underlying mechanisms of the ethanol extract of A. officinarum rhizomes in an indomethacin-induced gastric injury rat model. Material and methods: Indomethacin (0.3 g/kg) was orally administered to Sprague-Dawley rats to induce gastric damage; after 7 h, the rats were treated with 0.03, 0.09, or 0.18 g/kg of the plant extract, galangin (0.2 g/kg), or bismuth potassium citrate (0.08 g/kg), once a day for 6 days. Rats in the control group received an equivalent volume of vehicle solution for 6 days. Gastric damage was evaluated by gross ulcer and histological indexes. Cyclooxygenase and non-cyclooxygenase pathway proteins were quantified by western blotting and ELISA. Results: Alpinia officinarum extract ameliorated gastric injury in a dose-dependent manner, and 0.18 g/kg dose exhibited the best performance by reducing the gross ulcer (from 20.23 +/- 1.38 to 1.66 +/- 0.37) and histological (from 4.67 +/- 1.03 to 0.33 +/- 0.51) indexes, decreasing serum TNF-alpha level (14.17%), increasing serum VEGF level (1.58 times), increasing cyclooxygenase-1 level (1.25 times, p < 0.001) in the gastric mucosa, and reversing indomethacin-induced changes in the expression of non-cyclooxygenase pathway proteins (p < 0.05). Galangin was less effective as an antiulcer agent than the whole extract, indicating that other components also contributed to the protective effect. Conclusions: Alpinia officinarum extract and galangin exert antiulcer effects through cyclooxygenase and non-cyclooxygenase pathways validating use of galangin as a treatment for gastric damage.