| Literature DB >> 19127724 |
Freddy A Ramos1, Yoshihisa Takaishi, Miki Shirotori, Yousuke Kawaguchi, Koichiro Tsuchiya, Hirofumi Shibata, Tomihiko Higuti, Tetsuo Tadokoro, Minoru Takeuchi.
Abstract
Four new quercetin-derived oxidation products (1-4) and lunularin-4-O-beta-D-glucoside (5) were isolated from a water extract of onion (Allium cepa) skin, together with 17 other known compounds. Antibacterial assays for the isolated compounds showed that 2-(3,4-dihydroxyphenyl)-4,6-dihydroxy-2-methoxybenzofuran-3-one (1) presented selective activity against Helicobacter pylori strains and 3-(quercetin-8-yl)-2,3-epoxyflavanone (4) showed antibacterial activity against MRSA and H. pylori strains at the same time that it increased susceptibility of MRSA to beta-lactams. Evaluation of antioxidant activity against DPPH for the isolated compounds showed that the new derivative compounds (1-4) and 2,5,7,3',4'-pentahydroxy-3,4-flavandione (6) are more active than quercetin.Entities:
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Year: 2006 PMID： 19127724 DOI： 10.1021/jf060251c
Source DB: PubMed Journal: J Agric Food Chem ISSN： 0021-8561 Impact factor: 5.279