山藥塊莖儲藏性蛋白質及其水解產物之抗氧化活性研究

Studies on the antioxidant activities of the major tuber storage proteins of yam and their hydrolysates

劉燕雯(Yen-Wenn Liu)

指導教授 ： 侯文琪

臺北醫學大學/藥學院/生藥學研究所/碩士(2002年)

摘要

本研究以不同品種山藥 (Dioscorea spp.) 塊莖之儲藏性蛋白質dioscorin為材料，包括：省產台農1號山藥 (Dioscorea alata L. cv. Tainong 1) 與進口日本山藥 (Dioscorea batata Decne)，將塊莖粗抽液，經由DE-52離子交換管柱層析分離純化得到山藥儲藏性蛋白質：dioscorin。經由一系列抗氧化試驗，包括DPPH自由基清除、氫氧自由基清除、超氧自由基清除、還原力、抗脂質過氧化、抗低密度脂蛋白氧化、DNA保護作用及抑制peroxynitrite造成的dihydrorhodamine 123氧化作用，由實驗結果得之dioscorin具有抗氧化活性。以省產台農1號山藥為植物材料，分離純化得到之山藥儲藏性蛋白質dioscorin，進一步以胃蛋白酶 (pepsin) 與胰蛋白酶 (trypsin) 進行不同時間的水解試驗，來探討山藥儲藏性蛋白質胃蛋白酶與胰蛋白酶水解產物之抗氧化活性，發現隨著水解時間加長，其水解產物抗DPPH自由基活性增多，其中以32小時為最高。將水解產物以Sephadex G-50(F) 膠體過濾管柱層析，分離水解後所得到之多胜肰，並以DPPH自由基清除活性來區分水解物抗氧化活性。收集分子量較小的多胜肰，再以Sephadex G-25(M) 膠體過濾管柱層析，以DPPH自由基清除活性來區分水解物抗氧化活性，結果顯示，小分子區分仍具有清除DPPH自由基活性。

關鍵字

抗氧化 ； 山藥主要儲藏性蛋白質 ； 山藥 ； 儲藏性蛋白質

並列摘要

Abstract Dioscorin, the major tuber storage protein of Dioscorea spp. has been reported to behave many enzyme activities, such as carbonic anhydrase, trypsin inhibitor, dehydroascorbate reductase, and monodehydroascorbate reductase. In recent study, it was showed that dioscorin exhibited antioxidant activities, including DPPH radical and hydroxyl radical scavenging activities. In this study, both of Dioscorea alata L. cv. Tainong 1 (Tainong No.1 yam) and Dioscorea batatas Decne (imported from Japan) were used as plant material for comparisons. Dioscorins were purified by DE-52 ion exchange chromatography from crude extracts of yam tubers. By a series of in vitro tests, including DPPH radical and hydroxyl radical scavenging activity assay, reducing power test, anti-lipid peroxidation test, and anti-human low density lipoprotein (LDL) oxidation test, DNA damage protection, and inhibition of dihydrorhodamine 123 oxidation by peroxynitrite, it was showed that dioscorin exhibited antioxidant activities. Using dioscorins (purified from Tainong No.1 yam) as materials for pepsin and trypsin hydrolysis, it was showed that the pepsin hydrolysates also exhibited antioxidant activities against DPPH radical, and the 32 h hydrolysates got the hightest one. The hydrolysates were loaded onto Sephadex G-50(F) gel filtration chromatography, and each fraction was tested for DPPH radical scavenging activity assay. It was showed that the smaller molecule weight fractions still have antioxidant activities. The active fractions were collected and loaded onto Sephadex G-25(M) gel filtration chromatography, and each fraction was also tested for DPPH radical scavenging activity assay.

並列關鍵字

antioxidant ； dioscorin ； yam ； storage protein

參考文獻

Hou, W.C., Chen, H.J., and Lin, Y.H. Dioscorins from different Dioscorea species all exhibit both carbonic anhydrase and trypsin inhibitor activities. Bot. Bull. Acad. Sin. 2000, 41, 191-196.

參考文獻 Aderiye, B.I., Ogundana, S.K., Adesanya, S.A., Roberts, M.F. Antifungal properties of yam (Dioscorea alata) peel extract. Folia Microbiologica. 1996, 41(5), 407-12.

Andersen, M.L., Outtrup, H., Skibsted, L.H. Potential antioxidants in beerassessed by ESR spin trapping. Journal of Agricultural & Food Chemistry. 2000, 48(8), 3106-11.

Aderiye, B.I., Ogundana, S.K., Adesanya, S.A., Roberts, M.F. Antifungal properties of yam (Dioscorea alata) peel extract. Folia Microbiologica. 1996, 41(5), 407-12.

Araki, T., Kuramoto, M., Torikata, T. Positions of disulfide bonds in yam (Dioscorea japonica) acidic class IL (class IV) chitinase. Archives of Biochemistry & Biophysics. 1996, 335(1), 118-22.