Constituents of the leaves of Woodfordia fruticosa Kurz. I. Isolation, structure, and proton and carbon-13 nuclear magnetic resonance signal assignments of woodfruticosin (woodfordin C), an inhibitor of deoxyribonucleic acid topoisomerase II.

Development of a bioassay-coupled HPLC-SPE-ttNMR platform for identification of α-glucosidase inhibitors in apple peel (Malus × domestica Borkh.)

“…Compound 1 3 Hz, H-1 00 ), 3.78 (dd, J = 11.7, 5.2 Hz, H-5 00 eq), 3.51 (dd, J = 8.9, 7.3 Hz, H-2 00 ), 3.50 (m, H-4 00 ), 3.40 (dd, J = 8.9, 8.6 Hz, H-3 00 ), 3.10 (dd, J = 11.7, 9.5 Hz, H-5 00 ax) identified as reynoutrin (quercetin-3-O-b-D-xylopyranoside) (Kadota et al, 1990) and by comparison with a 1 H NMR spectrum of a reynoutrin standard.…”

“…Thus, 1 was identified as (À)-epicatechin (Hsieh et al, 2008), 2 as hyperin (quercetin-3-O-b-D-galactopyranoside) (D'Agostino et al, 1992), 3 as reynoutrin (quercetin-3-O-b-D-xyloside) (Kadota et al, 1990), 4 as avicularin (quercetin-3-O-a-L-arabinofuranoside) (Zhang et al, 2005), and 5 as quercitrin (quercetin-3-O-a-Lrhamnopyranoside) (Jayaprakasha et al, 2006). All structures are shown in Fig.…”

The Polyphenolic Ellagitannin Vescalagin Acts As a Preferential Catalytic Inhibitor of the α Isoform of Human DNA Topoisomerase II

“…Initial studies led to the isolation and the identification of hydrolyzable dimeric ellagitannins such as woodfruticosin (Kadota et al, 1990) or sanguiin H-6 , as the active principal responsible for the anti-Top2 activity of these extracts. A more detailed analysis of 60 derivatives belonging to different classes of tannins, gallotannins, glucopyranosic ellagitannins, C-glucosidic ellagitannins, condensed tannins, and other tannins with complex structures, revealed that 36 compounds were at least more than 100-fold more potent than etoposide in inhibiting Top2 activity in vitro .…”

Phytochemical Studies of Korean Endangered Plants: A New Flavone from Rhododendron brachycarpum G.Don

“…Consequently, the structure of compound 1 was elucidated as caryatin-3' methyl ether-7-O-α-L-rhamnoside. The known polyphenols were identified as 3,3',7-trihydroxy-4',5-dimethoxyflavone (2), 12 hyperin (3), 13 guaijaverin (4), 14 taxifolin-3-β-D-xylopyranoside (5), 15 (+)-catechin (6), 16 (+)-gallocatechin (7), 17 and (−)-epicatechin (8) (Figure 1) by comparison of the experimental and reported spectroscopic data. Of the known flavonoids, compounds 2 and 5 were isolated from R. brachycarpum for the first time.…”