7-O-Methylquercetin 3-O-R-L-rhamnopyranoside (5): [R]D -119.8°
(MeOH; c 0.5); IR, î (KBr) cm-1 3747, 3337, 2361, 1653, 1596, 1209;
UV, ìmax nm 349, 256 (MeOH), 395, 264 (NaOMe), 396, 273 (AlCl3),
400, 362, 271 (AlCl3 + HCl), 349, 256 (NaOAc), 369, 260 (NaOAc
+ H3BO3); 1H NMR (CD3OD), ä 0.94 (3H, d, 6.2 Hz, H-6¢¢), 3.33
(1H, t, 9.5 Hz, H-4¢¢), 3.43 (1H, dq, 9.5, 6.2 Hz, H-5¢¢), 3.74 (1H, dd,
9.5, 3.2 Hz, H-3¢¢), 3.88 (3H, s, 7-OMe), 4.21 (1H, dd, 3.2, 1.7 Hz,
H-2¢¢), 5.36 (1H, d, 1.7 Hz, H-1¢¢), 6.33 (1H, d, 2.3 Hz, H-6), 6.57
(1H, d, 2.3 Hz, H-8), 6.90 (1H, d, 8.4 Hz, H- 5¢), 7.32 (1H, dd, 8.4,
1.9 Hz, H-6¢), 7.35 (1H, d, 1.9 Hz, H-2¢); 13C NMR (CD3OD), ä 17.7
(C-6¢), 56.5 (7-OMe), 71.9 (C-2¢¢), 72.0 (C-5¢¢), 72.1 (C-3¢¢), 73.3 (C-
4¢¢), 93.1 (C-8), 99.0 (C-6), 103.6 (C-1¢¢), 106.8 (C-10), 116.4 (C-5¢),
117.0 (C-2¢), 122.8 (C-1¢), 122.9 (C-6¢), 136.4 (C-3), 146.5 (C-3¢), 150.1
(C-4¢), 158.4 (C-2), 159.7 (C-9), 163.0 (C-5), 167.3 (C-7), 179.8 (C-
4); FAB-MS (positive), m/z 463 [M + H]+.
Online RP-HPLC-DPPH Screening Method for Detection of Radical-Scavenging Phytochemicals from Flowers of Acacia confusa
By Wu, Jyh-Horng; Huang, Chih-Yu; Tung, Yu-Tang; Chang, Shang-Tzen
From Journal of Agricultural and Food Chemistry (2008), 56(2), 328-332. |