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URN etd-0904108-134729 Statistics This thesis had been viewed 4627 times. Download 3307 times. Author Shu-ting Chang Author's Email Address No Public. Department Bioengineering Year 2007 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 100 Title valuation for antioxidative activities and cytotoxicities of carotnnoids from halophilic Haloferax mediterranei Keyword cytotoxic halobacterium carotenoid antioxidation antioxidation carotenoid halobacterium cytotoxic Abstract An extracted red pigment from Haloferax mediterranei (hmERP) contains three kinds of C50 carotenoids. These three kinds of C50 carotenoids can be isolated by eluting of 40% ethyl acetate in hexane, ethyl acetate, and methanol from silica gel column chromatography. The purified carotenoids were named hmC1, hmC2, and hmC3 according to the order of elution from silica gel column chromatography.
Adding 50 μM hmC3 and the same concentrations of trolox, butylated hydroxyanisole (BHA), or β-carotene, the DPPH radical scavenging ability, total antioxidative activity, and reducing power of hmC1 were 80%, 1.7 folds, and 4.0 folds of trolox as well as 1.7 folds, 4.1 folds, and 7.5 folds of β-carotene, respectively. These abilities of hmC3 were similar or better than BHA. Additionally, the chelating effect on ferrous ions was measured as 42%, and was 77% of 50 μM EDTA. However, trolox, BHA, and β-carotene were few or no ferrous ions chelating ability. For the assessment of the superoxide-scavenging ability, the IC50 of hmC3, trolox, and BHA were 0.275 mM, 8.69 mM, and 25.70 mM, respectively; the ability of β-carotene was too weak to be detected. It’s obvious that the hmC3 has excellent antioxidant activity and its ability is better than β-carotene.
Incubation of the hepatocellular carcinoma HepG2 and Hep3B cells and human skin fibroblast CCD-966SK cell with hmERP and these 3 kinds of purified carotenoids, the cell viabilities by MTT assay were determined. No apparently toxicity to cells treated with the 0-0.5 ppm hmERP and 0-1000 nM hmC3 within 6 h was observed, but it was toxic for these cells treated with in 24 h and was in a dose dependent manner. The LD50 of CCD-966SK, Hep3B, and HepG2 cells were 334 nM, 165 nM, and 122 nM, respectively. However, the viability of CCD-966SK cells is above 80% when the treatment concentration was lower than 200 nM. One hundred nM of the other two carotenoids (hmC1 and hmC2) had no or few toxicity to the HepG2 and Hep3B cells. In addition, the LD50 of B16-F0 melanoma cell was 8.5 nM when it was treated with hmC3 for 24 h. Meanwhile, the melanin contents of B16-F0 cells treated with hmC3 for 24 h and 48 h did not decrease.
Advisor Committee Ming-tse Lin - advisor
Files Date of Defense 2008-06-17 Date of Submission 2008-09-05