- 著者
- Takashi NAKAMURA Katsuyuki SATO Mitsuo AKIBA Masao OHNISHI
- 出版者
- Japan Oil Chemists' Society
- 雑誌
- Journal of Oleo Science (ISSN:13458957)
- 巻号頁・発行日
- vol.55, no.4, pp.191-197, 2006 (Released:2006-03-14)
- 参考文献数
- 16
- 被引用文献数
- 4 12
In these experiments, the antioxidative activity of urobilinogen, a major fecal pigment-related compound and reduced metabolite of bilirubin, was shown. Urobilinogen was synthesized from commercial bilirubin by reduction, and the structure was confirmed with mass spectroscopy and NMR analyses. The product was identified as i-urobilinogen. The DPPH radical scavenging activity of urobilinogen was higher than other antioxidants (α-tocopherol, bilirubin and β-carotene). Moreover, the formation of hydroperoxides of linoleic acid with 2, 2’-azobis (2, 4- dimethylvaleronitrile) in methanol was suppressed by the addition of synthesized urobilinogen. On the other hand, in the NMR spectrum measurement, we found the signal decrease of a proton from C10 methylene. It was shown that this proton was exchanged with a deutrium of CD3OD. This methylene can easily release the hydrogen as proton donor. These results suggest that urobilinogen can inhibit the radical chain reaction by trapping free radicals.
- 著者
- Katsuyuki Sato Takae Nagasawa Takafumi Kasumi
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- pp.jag.JAG-2021_0011, (Released:2021-12-25)
- 被引用文献数
- 1
We previously demonstrated that the organogermanium compound 3-(trihydroxygermyl)propanoic acid (THGP) enhances the enzymatic and alkaline isomerization of an aldose to a ketose through cis-diol complex formation by multiple mechanisms. Its higher affinity for the ketose than the aldose protects the ketose complex from alkaline decomposition. Furthermore, it has been reported that the aldose-ketose alkaline isomerization pathway includes 1,2-enediol. Therefore, we speculated that the complex-forming ability of THGP could also be applied to enediol, a transient intermediate of alkaline isomerization. To test this prediction, we analyzed the initial rates of glucose or lactose isomerization in a region where there was no substantial difference in pH with and without THGP addition. The results showed that THGP enhanced the rate of fructose or lactulose formation per unit time by approximately 2-fold compared to the control. This finding indicated that THGP could form a complex with the transition state of aldose-ketose alkaline isomerization.
- 著者
- Takae Nagasawa Katsuyuki Sato Takafumi Kasumi
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- pp.jag.JAG-2019_0012, (Released:2019-10-24)
- 被引用文献数
- 6
Lactulose, a keto-type disaccharide widely used in pharmaceuticals and functional foods, is produced by the isomerization of lactose. The organogermanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) is an effective reaction promoter for the conversion of lactose to lactulose because of its high affinity to ketoses. Herein, an effective method for the continuous production of lactulose syrup was developed using Ge-132 through the alkaline isomerization of lactose in a bench-scale plant. This plant carried out a continuous isomerization process using Ge-132, continuous two-step separation process for separating the sugar and Ge-132, a continuous purification and concentration processes for the lactulose syrup, and separation and purification processes for the recovery of Ge-132. In this bench-scale plant, lactulose-containing syrup (350 g/L lactulose, 92 g/L lactose, and 31 g/L galactose) was prepared. The syrup was produced at a rate of 37.7 mL/h, and the content of residual Ge-132 in the syrup was 2 mg/L. The separation process was a two-step separation system requiring an ordinary electrodialyzer and an electro deionizer, which allowed the separation of more than 99.6 % Ge-132 from the reaction mixture. Moreover, the majority of Ge-132 and sodium hydroxide were recovered through electrodialysis using a bipolar membrane. The proposed system is the first to represent the novel development of an effective continuous production system for lactulose-containing syrup on the basis of the use of organogermanium compounds and incorporation of the electrodialysis technology.