欖仁樹(Terminalia catappa L.)為使君子科的植物,廣泛分佈於亞
洲各地.在菲律賓,印尼及馬來西亞等東南亞國家,其樹葉,樹皮和果實等皆
為民間藥,分別有止瀉,解熱與止血的功能,近年來在臺灣民間則以乾枯落
葉煎水作為保肝茶飲.而在先前本科室的相關研究報告中,也證實欖仁葉確
實具有保肝及抗炎症的效果,且藥效可能與其抗氧化活性有關. 欖仁樹
葉部之成份研究報告指出,其成份以加水分解型鞣質為主,包含punicalin,
punicalagin, chebulagic acid, geraniin等等.為了更進一步究明欖仁
葉之保肝活性成份及藥理作用,本研究以欖仁葉分離出之十種鞣質成份進
行抗氧化活性測試,以氯化亞鐵-抗壞血酸-誘發脂質過氧化實驗測定各成
份抗脂質過氧化之能力,以細胞色素c還原比色法及電子自旋共振法觀察各
成份對氧自由基之清除作用,以黃嘌呤氧化酵素抑制系統測試各成份抑制
自由基生成的效果.由於上述研究之結果顯示欖仁葉所含鞣質主成份
punicalagin及punicalin具有良好的抗氧化活性,於是以此二種成份進一
步來進行一連串抗炎及保肝作用活性測試,以角叉菜誘發大白鼠足蹠浮腫
實驗模式來評估其抗炎活性,以四氯化碳和對位乙醯胺酚誘發大白鼠急性
肝損傷實驗模式來評估其保肝活性,並進行肝臟脂質過氧化值及抗氧化酵
素活性之分析以探討藥物抗氧化與保肝作用活性之相關性. 抗氧化測
試之結果證明各成份均具有良好的抗氧化活性,而punicalagin及
punicalin亦具有良好的抗炎症及保肝活性.但值得注意的是,當兩成份劑
量提高時保肝效果反而降低,此現象和欖仁葉水抽出物之研究結果相同,且
經由實驗證明兩成份雖具有緩解四氯化碳及對位乙醯胺酚毒性之效果,但
使用過量時其本身亦具有肝損傷毒性.

"Terminalia catappa L." is a Combretaceous plant broadly
distributed in tropical and subtropical beaches. Reports
concerning the constituents of the leaf of this plant are
chiefly about hydrolyzable tannins such as punicalagin,
punicalin, chebulagic acid, geraniin, etc. In our previous
studies, we observed that the water extracts of T. catappa had
good antioxidant, anti-inflammatory and hepatoprotective
activities. In studies of the antioxidant effects of these
tannins, we tested the activities of lipid peroxidation
inhibition, superoxide anion scavenging and xanthine oxidase
inhibition. All of them had strong antioxidant activities.
Punicalagin and punicalin were isolation from the leaves of T.
catappa, and showed strongest antioxidant activity. Therefore,
the anti-inflammatory and hepatoprotective effects of
punicalagin and punicalin in the rats were be evaluated. In
these studies, we evaluated of their anti-inflammatory effects
on carrageenan-induced paw edema and hepatoprotective activity
on CCl4- and acetaminophen-induced acute hepatotoxicities in
rats. The results showed that punicalagin and punicalin had
anti-inflammatoryand hepatoprotective effects, but the larger
doses of both components were induced the liver damage. These
results indicated that even if tannins had strong antioxidant
activity in a very small dose, but a larger dose will induced
cell damage.