| Summary: | 碩士 === 國立嘉義大學 === 食品科學系研究所 === 98 === Reactive dicarbonyl species have drawn much attention in recent decades, it has been demonstrated that reactive dicarbonyl species irreversibly modified proteins over time and yielded the advanced glycation endproducts (AGEs). AGEs in the body were confirmed to be proportional to many diseases』 markers. For example, blood levels of dicarbonyl were found higher in diabetic patients than in healthy individuals. The aim of the present study is to find the substances that can reduce methylglyoxal (MG) in vivo or in vitro, in order to prevent cell injury and the AGE production. Twenty-one simple phenols, extracts of black currant, and oligonol have been evaluated for MG trapping ability. The relationships between reaction activity and physical and chemical properties of phenolic compounds were discussed further. Computer software, CS ChemDraw Ultra 11.0.1 (Copyright c 1986-2007 by Cambridge Soft Corporation (CS)) was used for the calculation of electron charges.
MG trapping was done under simulated physiological conditions (pH 7.4 and 37 °C). MG molecule is small and volatile, therefore no absorption in UV/Vis. The quantification of MG was based on the detection of its derivative compound, 2-methylquinoxaline (2MQ), at 313 nm in HPLC analysis.
The results showed that after reacting with black currant extract and oligonol, MG reduction rates are 36.11 ± 7.19 % and 47.68 ± 0.66 %, respectively. Both showed effective MG trapping ability. Black currant extract was then further separated and purified to obtain the main anthocyanidins within to investigate the MG trapping percentages and the addition reaction between individual anthocyanidin and MG. Black currant extract was first separated using Sephadex LH-20 chromatography. After analysis by LC-ESIMS, Delphinidin-3-O-rutinoside (D3R) and Cyanidin 3-O-rutinoside (C3R) were identified as main anthocyanidins. This particular fraction then passed through HPLC sorbents octadecyl (C18) 15-40μm chromatography again for collection of D3R and C3R. In order to study the stability of D3R and C3R under heat, both were set in 37 ℃, reaction for 1 hour. The reduction rates of D3R and C3R were 28.60 ± 2.30 % and 21.26 ± 1.07 %, respectively. D3R and C3R also reacted with MG in 37 ℃ for 1 hour. The reduction rate of D3R and C3R were 96.52 ± 0.21 % and 97.67 ± 0.08 %, respectively. Therefore, D3R and C3R were not heat-stable and reacted with MG. The MG trapping ability of D3R and C3R were 46.72 ± 0.76 % and 49.80 ± 0.56 %. C3R showed better ability than D3R did. This illustrated that one extra OH existed on B ring of D3R caused the difference in MG trapping ability. It was also found that after reaction, D3R and C3R appeared to have one MG addition when analyzed by LC-ESIMS.
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