| Summary: | 碩士 === 國立嘉義大學 === 食品科學系研究所 === 101 === Graptopetalum paraguayense belongs to the family Crassulaceae, the genus Graptopetalum. According to the previous research, G. paraguayense displayed the activities of antioxidant, hepatoprotective and anti-hepatocellular carcinoma. However, the active ingredient has not been suffer lots of attentions. In this study, we will isolate G. paraguayense water extract within different solvent including n-hexane, ethyl acetate and n-butanol, evaluate the antioxidant and antiglycative activities of different fractions, and identification the active compounds with LC-MS/MS and NMR. As the result, in the part of antioxidant, ethyl acetate fraction possess the best activity, the IC50 of DPPH scavenging effects and total antioxidant are 120 and 230 μg/mL. The total phenolics and total flavonoids are 83.69 mg gallic acid equivalent/g and 45.43 mg quercetin equivalent/g. In the system of BSA/fructose glycation, the ethyl acetate fraction has the best inhibition against fluorescent advanced glycation end-products (AGEs), the IC50 is 70 μg/mL. In addition, assessment the inhibition activities of ethyl acetate fraction against glycation early product (fructosamine), glycation-induced protein oxidation and the intermediate product (α-dicarvonyl compounds), the IC50 are respectively 282, 70 and 141 μg/mL, which illustrate the potentiality of antiglycation from ethyl acetate fraction. Use the HepG2 as the experiment mode, evaluate the protection effect of DNA damage induced by AGEs from ethyl acetate fraction. As the result, the HepG2 cell will be highly damaged cell when induced by AGEs (10 mg/mL), and the % Tail DNA will reduced 43.27% from 84.70% when cotreatment with ethyl acetate fraction (800 μg/mL), which indicated that ethyl acetate fraction possess great repair effect on DNA damage from AGEs.
Antioxidant and antiglycation experiment as the filter platform, ethyl acetate fraction possess the best activities, so we identify the active ingredient of this fraction. Use the HPLC semi-preparative column purifies the five major peaks of ethyl acetate fraction, and identification the structure of five compounds by LC-MS/MS and NMR. The five compounds is identify as gallic acid, quercetin 3-O-β-D-
glucopyranoside-6〞-(3-hydroxy-3-methylglutarate), kaempferol 3-O-β-D-glucopyranoside-6〞-(3-hydroxy-3-methylglutarate), quercetin 3-O-β-D-glucopyranoside-2〞-acetyl-6〞-(3-hydroxy-3-methylglutarate) and kaempferol 3-O-β-D-glucopyranoside-2〞-acetyl-6〞-(3-hydroxy-3-methylglutarate). The previous five compounds are 23.24, 90.52, 23.23, 77.35 and 40.60 mg from one g of ethyl acetate fraction. Compare the DPPH scavenging, total antioxidant and fluorescent AGEs inhibition of five compounds on the same concentration (0.1 mM), gallic acid display the best inhibition effect from five compounds. In summary, the ethyl acetate fraction from G. paraguayense display the best antioxidant and antiglycative activities, and gallic acid may provide the major activity, the results can be the basis of health products development.
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