本論文分為兩部分,第一部分為稜果蒲桃 Eugenia uniflora L



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  • 本論文分為兩部分,第一部分為稜果蒲桃 ( Eugenia uniflora L. ) 之 新單寧成分研究,第二部分為單寧及其相關成分之生理活性,包括對癌細 胞株毒性之機轉探討與 Epstein-Barr virus (EBV) DNA polymerase 之 抑制作用。近坍來有關單寧之活性,例如:抗腫瘤、抗病毒、抗氧化等文 獻陸續增多。更由於臺灣植物資源豐富,而單寧又廣布於植物體中,因此 本論文乃自桃金孃科 (Myrtaceae) 植物中進行初篩,再以本研究室由枯 里珍 ( Antidesma pentandrum var. barbatum)[Euphorbiaceae] 分離之 新二量體 (dimer) 加水分解型單寧- antidesmin A 為指標成分,以高 效能液相層析法 (HPLC) 進行成分分析,初步確定此科之植物-稜果蒲桃 含有二量體以上之成分。其乾燥葉以 70% acetone 萃取,經不同之層析 管柱進行分離與純化,得到 6 種單寧,分別為 eugeniflorins D1, D2, oenothein B, 1,2,4,6-tetra-O-galloyl-β-D-glucose, gallocatechin 和 ellagic acid,其中的 eugeniflorins D1, D2 為新單寧成分。自稜 果蒲桃所分離得到之成分配合本研究室比照美國癌症研究所建立之細胞毒 性試驗模式,進行 KB cells, Hep3B cells 之體外試驗。具細胞毒性之 成分再以掃描式電子顯微鏡與穿透式電子顯微鏡觀察細胞形態之變化;同 時利用同位素嵌入大分子含量分析法,探討細胞中 DNA、RNA 與蛋白質生 合成之變化。另外亦以與鼻咽癌有關之 EB 病毒 的 DNA polymerase 為 指標,找尋有抑制活性之成分。結果發現 eugeniflorin D2 與 oenothein B 對癌細胞具毒殺作用,其對 KB 細胞之 IC50 分別為 39.43μg / ml 與 21.50μg / ml,對 Hep3B 細胞之 IC50 分別為 75.28μg / ml 與 77.12μg / ml,且對 Hep3B 細胞之 DNA、RNA 與蛋 白質之生合成均有抑制作用,且以對 RNA 與蛋白質之作用較明顯;在 EBV DNA polymerase 的抑制活性方面, eugeniflorins D1, D2 有強的 抑制活性,其 IC50 分別為 5.2 μg / ml 與 5.5 μg /ml。


  • There are two parts in the present study. The first part is a study on new compounds of tannins derived from Eugenia uniflora L. and the second part on the biological activities of tannins originated from E. uniflora in view of the mechanism of cell cytotoxicity and the inhibition of EBV DNA polymerase. The plants of Taiwan is very plentiful. Recently, tannins are well known to show a significant effect on antitumor, antiviral and antioxidative activities. In the present study, chemical methods (FeCl3 T.S., NaNO2-AcOH etc.) were used to screen polyphenolic compounds from different families (i.e. Euphorbia- ceae, Leguminosae, Lythraceae and Myrtaceae, etc.) which contained abundant tannins. Subsequently, by the analysis of HPLC, the identification was based on the reference component, antidesmin A (dimeric hydrolysable tannin), derived from Antidesma pentandrum var. barbatum Merr. in our laboratory. After isolation of the 70% acetone extract of dried leaves from E. uniflora, six compounds, eugeniflorins D1, D2, oenothein B, 1,2,4,6-tetra-O-galloyl-β-D-glucose, gallocatechin and ellagic acid, were obtained. Eugeniflorins D1 and D2, new hydroly-sable tannins dimers, were firstly found in the natural plants. The KB and Hep3B cells were employed in vitro to study the cell cytotoxic effects of the tannins derived from E. uniflora. The cytotoxicity of these cell lines were studied by the treatment of eugeniflorin D2 and oenothein B through the examination of both scanning and transmission electron microscopies. In the present study, the biosynthesis of DNA, RNA and protein were analyzed by radioactive incorporation. The EBV DNA polymerase associated with nasopharyngeal carcinoma was further ultilized as an index to survey the active components of tannins. Putting the data together, the present results demonstrated that both eugeniflorin D2 and oenothein B showed an evident cytotoxic effect on treated cells (for KB cells, IC50= 39.43μg / ml and 21.50μg / ml, respectively; for Hep3B cells, IC50=75.28μg / ml and 77.12μg / ml, respectively). They also inhibited the biosynthesis of DNA, RNA and protein of Hep3B cells, particularly, those of the latter two were significantly obstructed. In addition, eugeniflorin D1 and eugeniflorin D2 would obviously restrain the activity of EBV DNA polymerase (IC50=5.2μg / ml and 5.5μg / ml, respectively).




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