| 摘要: | 本研究探討基隆山藥乙醇萃取物及其活性成分薯蕷皂?元之抗氧化能力及對D-型半乳糖引起衰老小鼠之神經保護，本研究首先藉體外試驗來探討基隆山藥乙醇萃取物之抗氧化能力及抗氧化成分分析。動物實驗將小鼠分為(1)正常組 (2)衰老組 (3)基隆山藥乙醇萃取物及薯蕷皂?元低劑量組(4)基隆山藥乙醇萃取物及薯蕷皂?元中劑量組(5)基隆山藥乙醇萃取物及薯蕷皂?元高劑量組，從D-型半乳糖誘導第六週後，開始給藥四週。以水迷宮評估小鼠學習與記憶能力，並測定小鼠腦部組織SOD,GSH-Px活性及MDA含量變化，以探討基隆山藥乙醇萃取物及其活性成分薯蕷皂?元對D-型半乳糖引起衰老小鼠之神經保護效應，並以HPLC偵測薯蕷皂?元在基隆山藥乙醇萃取物中的含量。
本研究藉由基隆山藥之抗氧化成分分析(總多酚類、總類黃酮類、總黃酮醇類之成分含量測定)、抗氧化能力分析(Trolox 總抗氧化能力測定、FRAP抗氧化能力測定、DPPH自由基清除能力)體外抗氧化實驗發現，基隆山藥具有體外抗氧化作用，而薯蕷皂?元不具體外抗氧化作用。在水迷宮的實驗中，給予基隆山藥乙醇萃取物及薯蕷皂?元的小鼠與D-型半乳糖(200mg/kg 10週)引起衰老小鼠比較，發現明顯地改善小鼠的學習與記憶能力。另外發現在D-型半乳糖(200mg/kg 10週)引起衰老小鼠的大腦，基隆山藥乙醇萃取物及薯蕷皂?元能增加內源性抗氧化酵素SOD 、GSH-Px 的活性；降低MDA的濃度。HPLC檢測結果發現每公克基隆山藥乙醇萃取物含有5.49 mg的薯蕷皂?元。
綜合上述結果顯示，基隆山藥的抗氧化活性和多酚類具高度相關性，而薯蕷皂?元不具體外抗氧化作用。基隆山藥乙醇萃取物及薯蕷皂?元可改善D-型半乳糖引起衰老小鼠記憶損傷，其改善D-型半乳糖引起衰老小鼠記憶損傷之機轉是經由促進內源性抗氧化酵素的活性有關。
This study intended to assess the neuroprotective effect of yam (Dioscorea japonica Thunb. var. pseudojaponica (Hay.) Yamam.) and diosgenin on the senescent mice induced by D-galactose.The study intend to assay the antioxidative capacity and antioxidative component of yam in vitro experiments.The mice in the experiments were administered orally with yam (20, 100 or 500 mg/kg for 4 weeks, from the sixth week) or diosgenin (1, 5, 25 and 125 mg/kg, 4 weeks, from sixth week).The learning and memory abilities of the mice in Morris water maze test and the mechanisms involved in the neuroprotective effect of yam or diosgenin on the mice brain tissue were investigated. The content of diosgenin in the yam was also detected by using HPLC.
This study intended to explore the antioxidative component analysis of yam(total polyphenols,flavonoids,and flavonols assay),the antioxidative capacity of yam(Trolox total antioxidative capacity, FRAP antioxidative capacity determination, DPPH radical scavenging assay).The yam was found to possess antioxidative activity in vitro experiments.Diosgenin did not possess antioxidative activity.Mice treated withyamor diosgenin (5, 25 and 125 mg/kg, p.o.) were found to significantly improved their learning and memory abilities in Morris water maze test compared to those treated with D-gal (200 mg/kg for 10 weeks). In addition, yam or diosgenin (5, 25 and 125 mg/kg, p.o.)were also found to increase the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased the malondialdehyde (MDA) level on the brain of D-gal treated mice. Finally the amount of diosgenin in the yam is 5.49 mg/ g extract.
To sum up, the results indicated that the antioxidative activities of yam was related to polyphenols. Diosgenin did not possess antioxidative activity.Yam or diosgenin had the potential to be a useful treatment for cognitive impairment in TCMs. Its beneficial effect may be partly mediated via enhancing endogenous antioxidant enzymatic activities. |
