黃連水抽出物對大鼠的抗胃潰瘍作用

Antiulcerative Properties of Aqueous Extract of Coptidis Rhizoma in Rats

黃連是常用中藥之一，臨床上可應用於胃炎、胃出血等。其抗胃潰瘍作用雖有文獻報導，但作用機轉仍不甚明瞭。本實驗針對此，對黃連水抽出物的抗胃潰瘍作用進一步探討。黃連經由十二指腸投與，在較高劑量時，對幽門結紮大鼠具胃酸分泌抑制作用。黃連口服三十分鐘前處理，對經口投與酒精或酸化阿斯匹林所引起的胃黏膜損傷具保護作用，但對水浸拘束或皮下注射indomethacin所引起的胃潰瘍不具保護作用。黃連口服三十分鐘後，發現其胃內幾留體積明顯增加，顯示其具胃平滑肌鬆弛作用。胃平滑肌離體實驗也顯示，黃連對carbachol所引起的收縮具舒張作用。黃連經四小時前處理，結果對酒精或酸化阿斯匹林所引起的胃黏膜損傷不具保護作用，且胃內幾留體積也無明顯增加。這些結果顯示黃連的胃黏膜保護作用來自胃平滑肌的舒張。已有文獻指出胃平滑肌舒張作用可以稀釋腐蝕性物質的濃度，另一方面使黏膜褶層變平降低對腐蝕性物質的敏感性。胃黏膜中的前列腺素及含硫氫基化合物被認為對胃黏膜具保護作用。以前列腺素合成抑制劑indomethacin或含硫氫基化合物阻斷劑N-ethylmaleimide前處理，對黃連的胃黏膜保護作用及胃平滑肌舒張作用皆無影響，顯示前列腺素及含硫氫基化合物與黃連的作用無關。又黃連的主成分berberine 對胃黏膜不具保護作用。亦即berberine單獨不能代表黃連的作用。

We examined the mechanism of the protective effect of aqueous extract of Coptidis Rhizoma (ACR), a traditional Chinese medicine, on the gastric mucosa. ACR, given intraduodenally, inhibited the gastric acid secretion in pylorus-ligated rats. ACR, given orally 30min before the administration of ethanol and acidified aspirin, protected the gastric mucosa from these agents-induced gastric lesions, although it had no effect on the gastric lesions induced by indomethacin and water immersion stress. Oral administration of ACR increased gastric contents (muscle relaxation) when they were measured 30 min after ACR administration. ACR also relaxed carbachol-contracted gastric muscle in vitro. ACR neither increased gastric contents nor inhibited necrotizing agents-induced lesions when these were tested 4h after ACR administration. Treatment with indomethacin, which is a prostaglandin synthesis inhibitor, and N-ethylmaleimide, which is a sulfhydryl blocker, did not influence the effect of ACR either on gastric contents or on necrotizing agents-induced lesions. These results indicate gastric muscle relaxation plays an important role in the gastric protective mechanisms of ACR, and the endogenous prostaglandins and the sulfhydryl compounds are not necessary for the action of ACR.