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  • 學位論文

牛樟芝萃取物中與兩性黴素協同抗癌成分之探討

Study on components of Taiwanofungus camphoratus for anti-cancer synergistic effects with Amphotericin B

指導教授 : 蘇慶華

摘要


無資料

關鍵字

樟芝 兩性黴素B 協同作用

並列摘要


Our previous study on anti-tumor activity of Taiwanofungus cam-phoratus alcohol extract (TCAE) suggested that the treatment of TCAE on HT-29 colon cancer cell line not only promoted apoptosis but also conferred a synergistic effect by pretreating a small dose of TCAE at first and then combined with amphotericin B (AmB) of HT-29. AmB is a common antifungal agent used to treat systemic fungal infection by direct binding to ergosterol resulted in producing pore in fungal membrane which led to cell death. Therefore, we hypothesized that the extract of T. camphoratus contains a certain kind of sterol that has higher affinity to AmB and these sterols can easily replace the existing cholesterol in the cell membrane of cancer cells and then the replaced sterols became the target of AmB later on. The hypotheses also suggested the the phospholipid composition of cancer cells might be different from normal cells that attracted easier than normal cells to the sterols from T. camphoratus. Organic solvents in different polarity were employed to extract solid state cultivated T. camphoratus and n-hexane was found to be the most effective solvent for the extraction of AmB synergistic component to inhibit the growth HT-29 cell line other than TCAE. The n-hexane extract was separated by preparative thin layer chromatography (PLC) and two fractions (SB and LR) were found to be active in synergistic to AmB. SB demonstrated blue band under 254 nm UV and LR was a red color fraction under visible light spectrum with the yield around 0.01% for both fractions. MTT assay indicated that LR fraction had a low cytotoxicity to both HT-29 and normal cell HEK-293 when LR and SB is used alone with the relative survival rate at 80.87 % and 64.12 %, respectively. However, if 5μg/ml of LR was pretreated to HT-29 and combined with 3 μg/ml of AmB for 24 hr later, the survival rate was dropped to 47.3±3.88 %. Three components were obtained LR-LG, LR-1 and LR-R by further purification by PLC. LR-LG and LR-R were suggested to be the target components with a synergistic effect in dose dependent manner with AmB. The combined use of LR-LG / LR-R and AmB could be useful for the therapy of cancer for both the doses of LR-LG/LR-R and AmB can be minimized and less cytotoxicity was observed to normal cell in this administration system. The chemical structure of LR-LG and LR-R are under investigation.

參考文獻


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