@misc{oai:repo.qst.go.jp:00071435,
 author = {福原, 潔 and 今井, 耕平 and 中西, 郁夫 and 大野, 彰子 and 栗原, 正明 and 松本, 謙一郎 and 中村, 朝夫 and 今井 耕平 and 中西 郁夫 and 大野 彰子 and 松本 謙一郎},
 month = {Mar},
 note = {The development of antioxidants with strong radical-scavenging activities has attracted considerable attention in recent years for preventing oxidative stress related diseases.  Previously, we introduced methyl substituent ortho to the hydroxyl group of resveratrol, a natural phenolic antioxidant in red wine, leading to a very potent antioxidant with strong radical-scavenging activity.  The enhanced radical-scavenging activity may be attributed to the delocalization of an unpaired electron in the phenyoxyl radical generated in the reaction with radical species, due to hyperconjugation with the ortho methyl group.  Here, we synthesized quercetin analogues, where one or two ortho-positions of catechol hydroxyls are substituted with methyl groups.  Mono or dimethyl analogue of catechol was synthesized and reacted with hydroxyacetophenone to form hydroxychalcone, which was treated with alkaline hydrogen peroxide to give mono or dimethyl analogue of quercetin.  The antioxidative activities of mono and dimethyl analogues were examined using galvinoxyl radical as an oxyl radical species, showing 15-fold and 135-fold stronger radical-scavenging activities than that of quercetin, respectively.  These results prove that introduction of methyl substituents ortho to the hydroxyl group is effective for improving radical-scavenging activities of phenolic antioxidants., 17th Biennial Meeting of Society for Free Radical Research International (SFRRI 2014)},
 title = {Enhanced Radical-Scavenging Activities of C-Methylated Quercetin},
 year = {2014}
}