1998
DOI: 10.1021/np9800203
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Antioxidant Flavonoid Glycosides from Daphniphyllum calycinum

Abstract: A novel flavonoid diglycoside, 5,6,7,4'-tetrahydroxyflavonol 3-O-rutinoside (1), and a previously known compound, kaempferol 3-O-neohesperidoside (2), were isolated from an ethyl acetate extract of Daphniphyllum calycinum leaves that showed significant activity in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay. The structure of 1 was elucidated by a combination of spectroscopic methods, and compounds 1 and 2 were found to be moderately active as antioxidants in the DPPH assay.

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Cited by 99 publications
(47 citation statements)
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“…Part of the 1 H and 13 C NMR signals of compound 1 were observed in duplicate, suggesting a dimer ( Table 1). Comparison of the 13 C NMR values of 1 with literature data 13 evidenced the kaempferol aglycone and additional similar spectral features to those of 3, also isolated in this work, except for the duplication of some signals for carbons arising from a dimer structure. In the 1 H NMR spectrum of 1, signals for two kaempferol units as two meta-coupled A-ring hydrogens (H-6/H-8) and two pairs of coupled B-ring hydrogens (H-3'/H-5' and H-2'/H-6') for each aglycone were observed, in addition to four anomeric hydrogens at δ 5.12 (1H, d, J 7.7 Hz), 5.02 (1H, d, J 7.7 Hz), 4.40 (1H, br s), 4.60 (1H, br s), 20 hydroxymethine and 2 hydroxymethylene hydrogens.…”
Section: Resultssupporting
confidence: 82%
See 1 more Smart Citation
“…Part of the 1 H and 13 C NMR signals of compound 1 were observed in duplicate, suggesting a dimer ( Table 1). Comparison of the 13 C NMR values of 1 with literature data 13 evidenced the kaempferol aglycone and additional similar spectral features to those of 3, also isolated in this work, except for the duplication of some signals for carbons arising from a dimer structure. In the 1 H NMR spectrum of 1, signals for two kaempferol units as two meta-coupled A-ring hydrogens (H-6/H-8) and two pairs of coupled B-ring hydrogens (H-3'/H-5' and H-2'/H-6') for each aglycone were observed, in addition to four anomeric hydrogens at δ 5.12 (1H, d, J 7.7 Hz), 5.02 (1H, d, J 7.7 Hz), 4.40 (1H, br s), 4.60 (1H, br s), 20 hydroxymethine and 2 hydroxymethylene hydrogens.…”
Section: Resultssupporting
confidence: 82%
“…15 According to literature data, using the same solvent, the chemical shifts of hydroxymethines carbons in glucose are quite deshielded when compared to those of galactose. The glucosyl/galactosyl groups are linked to the rhamnosyl residue at C-6", because the signal assigned to this carbon, in both sugar moieties, was markedly displaced downfield at δ 67.1/65.9 (∆δ +6), respectively when compared with the 13 C NMR spectrum of free hydroxymethylenes in glucose/galactose. This also was confirmed by the observation of a HMBC long-range correlation of the anomeric hydrogen signal of the rhamnosyl group at δ 4.40 / 4.60 with C-6" of the glucosyl moieties at 67.1 and 65.9, respectively.…”
Section: Resultsmentioning
confidence: 99%
“…DPPH radical scavenging activity of the extracts (Qualiatative) The reduction of DPPH has been used to detect extracts with antioxidant activity, including those considered as free radical scavengers (Gamez et al,1998). Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The methanolic fraction was then fractionated and purified according to the antioxidant test. The active purified principles were analyzed for their chemical structures by IR, 13 C-NMR, 1 H-NMR, MS analyses and in comparison with the data of authentic quercetin [10][11][12], morin [13] and quercetin-3-O-glucopyranoside [14][15]. Results revealed the three active principles as compound 1, compound 2, and compound 3 as follows.…”
Section: Resultsmentioning
confidence: 99%