| 摘要: | 本研究目的是評估海巴戟天葉乙醇萃取物能否有效保護大白鼠體內血液與肝臟免於環磷醯胺（cyclophosphamide）的氧化性傷害。80 隻雄性大白鼠（Sprague-Dawley）隨機分成八組，並餵食AIN-76 動物飼料30天；其中一組大白鼠僅於實驗第15天腹腔注射磷酸鹽緩衝液，當作是控制組（C），而每天攝取每公斤體重0.2克海巴戟天葉 95% 乙醇萃取物（LE95） 的大白鼠為 LE1 組，其餘各組大白鼠分別於實驗第 15 天進行腹腔注射環磷醯胺，並每天攝食每公斤體重0.2克海巴戟天葉 50% 乙醇萃取物（CPLE50 組）、每天攝食 0克 LE95（CP組）、0.2克LE95（CPLE1組）、0.4克LE95（CPLE2組）、1克 LE95（CPLE5組），以及0.2克水飛薊（CPSL組）。實驗於第 30 天結束，並以乙醚麻醉且犧牲大白鼠，採集大白鼠腹腔動脈血，將分離出的血漿和血球，與肝臟組織分別進行抗氧化酵素活性和抗氧化能力的檢定，並進一步評估大白鼠經環磷醯胺誘發氧化傷害下，LE95對於活體內脂質和蛋白質保護的效果。
首先以C、CP、CPLE1、CPLE50和CPSL 五組進行單因數變異數分析（One-way ANOVA），並以Duncan’s test 做顯著性差異比較，評估攝食海巴戟天葉 50% 乙醇萃取物（LE50）、LE95 與水飛薊（silymarin）之間抗氧化能力的潛能。結果顯示攝食 LE95 或 LE50 對大白鼠遭受環磷醯胺誘發氧化壓力下，明顯優於公認有效的保肝劑水飛薊。此外，LE95 對於大白鼠肝臟和血液的抗氧化作用與保護效果，又比 LE50 所發揮的影響效果較顯著且趨於一致性。
在大白鼠遭受環磷醯胺誘發氧化壓力下，爲進一步探討攝取LE95 的劑量效應與LE95和環磷醯胺間之交互作用，對於大白鼠體內抗氧化作用與保護效果的影響，利用 NEST的實驗設計，以C、CP、LE1、CPLE1、CPLE2和CPLE5 六組進行單因數和多因數變異數分析（multiway ANOVA）進行統計。結果顯示：（1）攝取一倍劑量 LE95 的大白鼠在腹腔注射環磷醯胺 7天後，血球麩胱甘肽過氧化酶（GPx）的活性會上升；而在腹腔注射 15天後，則會提升血球麩胱甘肽還原酶（GRd）的活性；除此之外，還能夠減緩肝臟組織發炎、降低AST 活性並有維持相對肝重的效果。（2）攝取二倍劑量 LE95 的大白鼠在腹腔注射環磷醯胺 7天後，血球麩胱甘肽過氧化酶（GPx）的活性會上升；而在腹腔注射 15天後，則會提升血球觸酶（CAT）和血球超氧歧化酶（SOD）的活性；此外，還能夠降低AST 活性、提升肝臟組織中 NPSH、TSH 含量與增加清除 DPPH 自由基的能力。然而，CPLE2組出現相對脾重增加的特殊現象，可能是藉由增加脾臟細胞增生的速率抵抗該組溶血性貧血的結果。（3）攝取五倍劑量 LE95 的大白鼠能夠降低AST 活性、提升肝臟組織中 NPSH、TSH 含量與增加清除 DPPH 自由基的能力；然而，卻有較高的 MCH 値、加重血漿中蛋白質結構的氧化性傷害和降低遭受氧化壓力 15 天後血球觸酶（CAT）的活性，顯示攝取高劑量的 LE95 有加重氧化壓力，並引發大白鼠體內血液進一步受到氧化傷害的現象。
綜合以上結果顯示海巴戟天葉 95% 乙醇萃取物對於受到氧化壓力的大白鼠，在血液與肝臟上具有一些保護效果；然而，要發揮抗氧化作用和保護效果，與攝食LE95的劑量有關。
The aim of the present study was to evaluate the influence of ethanolic extracts of Noni leaves on the antioxidative properties of the blood and liver of rats exposed to cyclophosphamide. Eighty adult male Sprague-Dawley rats were divided into eight groups randomly and fed with AIN-76 diet for 30 days. One group was injected intraperitoneally with phospahte saline buffer on the fifteenth day and served as the control group（C）. The LE1 group was indicated that the rats received 95% ethanolic extracts of Noni’s leaves（LE95） at a dose of 0.2g/kg body weight per day. The others were fed with 50% ethanolic extracts of Noni’s leaves at a dose of 0.2（CPLE50）, LE95 at a dose of 0 （CP）, 0.2 （CPLE1）, 0.4（CPLE2）, 1（CPLE5）g/kg body weight or fed with silymarin（CPSL）at a dose of 0.2 g/kg body weight per day, and injected intraperitoneally with cyclophosphamide in phospahte saline buffer on the fifteenth day. After thirty days of administration, rats were sacrificed by ether anaesthesia. Blood of rat’s abdominal artery were drawn with an anticoagulant. Red blood cells, plasma and liver tissues were used for antioxidant enzymes or non-enzymatic antioxidants assays. Further study was to prove the 95% ethanolic extracts of Noni leaves（LE95）in the protection ability of lipid peroxidation and oxidative damage of protein caused by cyclophosphamide.
The first statistical analysis was to evaluate the antioxidative potential of the ethanolic extracts of Noni leaves（LE95 and LE50）in comparison with silymarin. The data were analyzed by one-way ANOVA with Duncan’s test for multiple comparisons to determine significance among C, CP, CPLE1, CPLE50, CPSL groups. The results implied that ethanolic extracts of Noni leaves had better antioxidative properties against oxidative stress induced by cyclophosphamide than silymarin which is well known as hepatic protective drug. Furthermore, LE95 appeared the marked and consistent antioxidative protection effects in rat livers and blood system, but not in LE50.
To further examine whether antioxidative protection effects of LE95 were also affected by the doses of LE95 and the interaction of LE95 with cyclophosphamide, a nested experimental design was evaluated. The data were analyzed by one-way and multiway ANOVA among C, CP, LE1, CPLE1, CPLE2, CPLE5 groups. The results indicated as following.（1）The rats received LE95 at a dose of 0.2g/kg body weight per day had higher the glutathione peroxidase activity（GPx） during 7 days and higher the glutathione reductase activity（GRd）during 15 days after cyclophosphamide administration in red blood cells than the other groups. In addition, a decrease of aspartate aminotransferase activity（AST）, normal hepatic tissue biopsy and normal relative liver weight were observed in rats dosed with 0.2g/kg body weight of LE95.（2）The rats received LE95 at a dose of 0.4g/kg body weight per day had higher the GPx during 7 days and higher the catalase（CAT）and superoxide dismutase activity（SOD）during 15 days after cyclophosphamide administration in red blood cells. In addition, a decrease of AST, increase hepatic NPSH, TSH contents and increase scavenging ability of DPPH in rat liver were observed. However, the dramatic increase of relative spleen weight in CPLE2 group. The result indicated that the rats received LE95 at a dose of 0.4g/kg body weight may act against hemolytic anemia by enhancement of the splenocyte proliferation rate.（3）The rats received LE95 at a dose of 1g/kg body weight per day could decrease AST, increase hepatic NPSH, TSH contents and increase scavenging ability of DPPH in rat liver. However, higher MCH value, higher carbonyl group’s content of plasma, and lower CAT during 15 days after cyclophosphamide administration in red blood cells were observed. These results implied that higher dosage of LE95 may appear aggravating oxidative damage in blood system of rats.
In conclusion, our results suggest that LE95 had some protection effects on blood and liver in rats from oxidative stress. However, the effectiveness of LE95 relates to the dose of usage. |
