@misc{oai:repo.qst.go.jp:00070379,
author = {Kawashima, Tomonori and Ohkubo, Kei and Fukuhara, Kiyoshi and Ozawa, Toshihiko and Anzai, Kazunori and Fukuzumi, Shunichi and Nakanishi, Ikuo and 川島 知憲 and 安西 和紀 and 中西 郁夫},
month = {Dec},
note = {Curcumin, a main and the most important yellow color component of turmeric, has been found to show antitumor and strong antioxidative activities. Antioxidative activity of CU is believed to be due to two 4-propenylphenol moieties in its molecule. On the other hand,CU also possesses an enolic structure, which may interact with metal ions in biological systems. A complex formation between CU and metal ions may affect the electron distribution in the CU molecule, resulting in change in the radical-scavenging activity of CU. In this study, we report to clarify the effect of metal ions on the radical-scavenging activity between CU. When CU was added to an acetonitrile (MeCN) solution of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), the absorption band at 519 nm due to DPPH• immediately decreased. This suggests that DPPH• is efficiently scavenged by CU. The scavenging rate constant (k) of DPPH• by CU was determined as 3.2 x 102 M–1 s–1 by the stopped-flow technique at 298 K. However, the k value was significantly decreased in the presence of 0.1 M Mg(ClO4)2 (k = 2.0 x 10 M-1 s-1), suggesting that CU interacts with magnesium ion (Mg2+). In fact, the spectral change was observed upon addition of Mg(ClO4)2 into the MeCN solution of CU. From the absorbance change at 441 nm was determined the binding constant (KM) between CU and Mg2+ as 3.0 x 102 M-1. Thus, the radical-scavenging activity of the Mg2+ complex of CU may be lower than that of CU. Effects of other bio-related metal ions on the radical-scavenging reaction of CU will also be discussed in this study., The 2010 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2010)},
title = {Effects of Metal Ions on the Radical-Scavenging Reactions by Curcumin},
year = {2010}
}