- Dihydrochalcones: Evaluation as novel radical scavenging antioxidants
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Dihydrochalcones are a family of bicyclic flavonoids, defined by the presence of two benzene rings joined by a saturated three carbon bridge. In the present study, we systematically examined the antioxidant activities of dihydrochalcones against the stable free radical (1,1-diphenyl-2-picrylhydrazyl) and lipid peroxidation in the erythrocyte membrane. All dihydrochalcones exhibited higher antioxidant activities than the corresponding flavanones. The 1H NMR analysis indicated that the active dihydrochalcone has a time-averaged conformation in which the aromatic A ring is orthogonal to the carbonyl group, while the inactive dihydrochalcone such as 2′-O-methyl-phloretin has a strongly hydrogen-bonded phenolic hydroxyl group, suggestive of a coplanar conformation. A hydroxyl group at the 2′-position of the dihydrochalcone A ring, newly formed by reduction of the flavanone C ring, is an essential pharmacophore for its radical scavenging potential.
- Nakamura, Yoshimasa,Watanabe, Shigeo,Miyake, Nobuyuki,Kohno, Hiroyuki,Osawa, Toshihiko
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p. 3309 - 3312
(2007/10/03)
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- PHENOLIC CONSTITUENTS FROM SEEDS OF COPTIS JAPONICA VAR. DISSECTA
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In addition to coumarinolignans (cleomiscosin A and aquillochin) and 7,4'-dihydroxy-5-methoxyflavanone, a new dihydrochalcone, 2',4,4'-trihydroxy-6'-methoxydihydrochalcone, was isolated from the seeds of Coptis japonica var. dissecta.The structure of the dihydrochalcone was confirmed by comparison with relevant synthetic samples. - Key Word Index: Coptis japonica var. dissecta; Ranunculaceae; cleomiscosin A; aquillochin; 2',4,4'-trihydroxy-6'-methoxydihydrochalcone; 7,4'-dihydroxy-5-methoxyflavanone.
- Mizuno, Mizuo,Kojima, Hiroyuki,Tanaka, Toshijuki,Iinuma, Munekazu,Kimura, Rie,et al.
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p. 2071 - 2074
(2007/10/02)
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