應用乙醯胺基苯酚誘導慢性肝炎損傷之動物模式探討薑精油與薑乙醇萃取物之護肝功效

Abstract

中文摘要 根據行政院衛生署九十七年國人十大死因報告，慢性肝病與肝硬化 (chronic liver disease and cirrhosis) 位居十大死因第八位，因此國人極需關切護肝相關議題。肝臟是人體最重要的解毒器官，主要可以分成Phase I (功能化作用) 及Phase II (共軛結合作用)，協助體內有毒物質轉化成無毒型式排出體外。乙醯胺基苯酚為常見解熱鎮痛藥物成分，服用過量時造成NAPQI異常累積，造成肝細胞毒性。本實驗首要目的為建立乙醯胺基苯酚所誘導肝損傷之慢性動物模式。經實驗評估大小鼠血液生化指標 (AST與ALT)、肝臟抗氧化狀態 (TBARS、GSH、GPx、GRd、SOD及CAT) 及病理進展，結果顯示BALB/c小鼠之模式最符合人體急 (慢) 性肝炎病理進展，因此推薦將此一模式應用於護肝健康食品功效評估。本研究另一目的為應用此合適動物模式評估薑精油與薑乙醇萃取物之護肝功效。薑之學名為Zingiber officinale Roscoe，使用水蒸氣蒸餾法與乙醇萃取法，分別得薑精油與薑乙醇萃取物。以急性實驗進行兩萃取物有效劑量篩選並分別定量其活性成分，結果顯示薑乙醇萃取物之急性護肝效果較佳，因此以此樣品進行慢性護肝效果評估。慢性實驗結果顯示，與APAP負對照組比較，處理薑乙醇萃取物之組別顯著降低肝功能指標酵素ALT及AST值，並且減緩肝臟GSH耗損以及提升抗氧化酵素GPx、SOD與CAT活性，亦可以調節肝臟解毒酵素GST以及CYP2E1活性，以利毒物排出，而由肝臟組織病理亦可證實薑乙醇萃取物可以減少APAP所引起之肝細胞損傷。薑乙醇萃取物於HPLC成分分析結果為每克生薑含有0.67 毫克薑辣醇 (6-gingerol)。綜合以上結果，薑乙醇萃取物可藉由提高抗氧化系統與調節肝臟解毒酵素，進而產生保護APAP誘導肝損傷的效果，並推測其可能有效抗氧化成分為薑辣醇。

Abstract According to the report of Department of Health of Taiwan in 2008, chronic liver disease and cirrhotic liver is the eighth of ten leading causes. Therefore, hepatoprotection has been an important issue in Taiwan. The hepatic detoxification includes Phase I (functionalization) and Phase II (conjugation). N-acetyl-p-aminophenol (APAP) is a widely used analgesic and antipyretic drug. In the case of APAP overdose, APAP is oxidized by liver at Phase I metabolism to generate N-acetyl-p-benzoquinone imine (NAPQI), which could cause hepatotoxicity. One aim of this study was to evaluate the applicable animal model of APAP-induced hepatotoxicity. In terms of the results of AST and ALT activities and anti-oxidative status, male BALB/c mice are the more applicable animal model of APAP-induced liver injury for evaluating hepatoprotection of health foods. The other aim was to evaluate the hepatoprotective effects of ginger essential oil (GEO) and ginger ethanolic extract (GEE). The GEO and GEE were extracted by steam distillation and 95% ethanol, respectively, from rhizomes of ginger (Zingiber officinale Roscoe). The acute results showed that 100 and 200 mg/kg GEE could significantly reduce the activities of AST and ALT (p<0.05); in contrast, not for the GEO groups. Therefore, GEE was further evaluated in chronic trial. The group treated with GEE for 4 weeks significantly reduced the activities of AST and ALT. GEE was able to reduce GSH depletion, modulate CYP2E1 and GST activities as well as increase activities of GPx, SOD, and CAT. Similar results were also revealed in pathological examination of liver. The GEE contained 0.67 mg of 6-gingerol, analyzed by HPLC. In conclusion, GEE may enhance the anti-oxidative system and modulate the hepatic detoxification while 6-gingerol may be the major antioxidant in GEE.