Antioxidant Flavonoid Glycosides from <i>Daphniphyllum </i><i>calycinum</i>

Gamez, E. J. C.; Luyengi, Lumonadio; Lee, S. K.; Zhu, Lei; Bin, Zhou; Fong, Harry H. S.; Pezzuto, John M.; Kinghorn, A. Douglas

doi:10.1021/np9800203

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%

“…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%

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New biflavonoid and other flavonoids from the leaves of Chimarrhis turbinata and their antioxidant activities

Cardoso¹,

Silva²,

Castro‐Gamboa³

et al. 2005

J. Braz. Chem. Soc.

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Um novo biflavonol denominado chimarrosídeo (1) e oito flavonóis glicosilados adicionais (2-9) foram isolados das folhas de Chimarrhis turbinata. Suas estruturas foram elucidadas com base nos dados dos experimentos de RMN 1D e 2D, como:Adicionalmente, a catequina (10) e a procianidina B-3 (catequina-(4α→8)-catequina) (11) também foram isoladas. O extrato bruto, frações e compostos isolados foram avaliados quanto às suas propriedades antioxidantes no teste em CCD aspergida com solução de β-caroteno, e teste espectrofotométrico utilizando o radical livre 1,1-difenil-2-picrilidrazila (DPPH). Os flavonóides 2, 5, 6, 10 e 11 apresentaram forte atividade antioxidante quando comparados com os padrões BHT e rutina.A new biflavonol, named chimarrhoside (1), and eight known flavonol glycosides (2-9), were isolated from the leaves of Chimarrhis turbinata. Their structures were established on the basis of 1D and 2D NMR experiments as quercetin-3-O-rutinoside (2), kaempferol-3-O-rutinoside -glucopyranoside (9). In addition, catechin (10) and catechin-(4α→8)-catechin-procyanidin B-3) (11) were isolated. The crude extract, fractions and isolated compounds were evaluated for their antioxidative properties using an autographic assay based on β-carotene bleaching on TLC plates, and spectrophotometric detection by reduction of the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. Flavonoids 2, 5, 6, 10 and 11 displayed strong free radical scavenging activity, when compared with the standards BHT and rutin.

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Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

New biflavonoid and other flavonoids from the leaves of Chimarrhis turbinata and their antioxidant activities

Cardoso¹,

Silva²,

Castro‐Gamboa³

et al. 2005

J. Braz. Chem. Soc.

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show abstract

“…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%

Free radical scavenging activity of crude extracts and 4´-o-methylepigallocatechin isolated from roots of cassine transvaalensis burtt-davy from botswana

Motlhanka¹,

Habtemariam²,

Houghton³

2010

African Journal of Biomedical Research

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Water and ethanol extracts of roots from Cassine transvaalensis Burtt-Davy (celastraceae) were assessed for in vitro antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. The ethanolic extract exhibited higher free radical scavenging effect than the water extract at all tested concentrations. Above 100µg/ml, the ethanolic extract showed 80% scavenging activity, similar to control antioxidant compounds quercetin, rutin and L-ascorbic acid. The water extract reached a similar level of activity (80%) at 200µg/ml. Between 20-50µg/ml, 4'-O-methylepigallocatechin isolated by bioassay directed fractionation exhibited scavenging activity greater than that of either the ethanolic or aqueous crude extract. However, at concentrations above 50µg/ml, the scavenging activity of the ethanolic extract exceeded that of 4'-O-methyl-epigallocatechin.The results suggest that extracts from the roots of Cassine transvaalensis have strong antioxidant activity. These findings support the ethnomedical use of this plant to promote good health.

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“…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%