LAUSR

Schisandra chinensis (Turcz.) Baill. is a well-known traditional Chinese medicine that has been used for a long time, especially in the folk medicine of northeastern China. This crude drug is officially recorded in the Chinese Pharmacopoeia as a tonic, sedative, and astringent agent [1]. In the health-food market, products containing S. chinensis are often claimed to possess antioxidant, neuroprotective, or liver-protective properties [2–5]. Chemically, a family of lignans and triterpenoids have been found in this plant, and many of them have shown biological activities [6]. However, most previous studies have focused on lignans and triterpenoids of the fruit and seed of S. chinensis but only a few on other constituents from the stems of S. chinensis. In the present paper, four flavonoid compounds, quercetin-3-O-D-xylopyranoside (1), isorhamnetin-3-OD-glucopyranoside (2), genistein-7-O-D-glucopyranoside (3), and catechin-7-O-D-glucopyranoside (4), were further isolated for the first time from the plant. Quercetin-3-O-D-xylopyranoside (1), mp 182–184 C (MeOH). HPLC-ESI-MS m/z 435.1 [M + H]+. IR (KBr, max, cm –1): 3347, 2935, 2864, 1634, 1610, 1548, 1057, 1027, 930, 799. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 7.72 (1H, d, J = 8.8, H-2 ), 7.54 (1H, d, J = 13.6, H-5 ), 6.84 (1H, d, J = 8.3, H-6 ), 6.36 (1H, s, H-8), 5.34 (1H, d, J = 7.1, H-1 ). 13C NMR (100 MHz, DMSO-d6, , ppm): 156.05 (C-2), 133.07 (C-3), 177.17 (C-4), 161.14 (C-5), 98.83 (C-6), 164.83 (C-7), 93.57 (C-8), 156.29 (C-9), 103.59 (C-10), 121.39 (C-1 ), 115.26 (C-2 ), 144.92 (C-3 ), 148.73 (C-4 ), 115.98 (C-5 ), 120.82 (C-6 ), 101.73 (C-1 ), 75.94 (C-2 ), 73.54 (C-3 ), 69.34 (C-4 ), 65.96 (C-5 ) [7]. Isorhamnetin-3-O-D-glucopyranoside (2), mp 167–170 C (MeOH). HPLC-ESI-MS m/z 479.1 [M + H]+. IR (KBr, max, cm–1): 3447, 2940, 1634, 1600, 1498, 1320, 1075, 875. 1H NMR (400 MHz, CD3OD, , ppm, J/Hz): 7.83 (1H, s, H-2 ), 7.49 (1H, d, J = 7.3, H-6 ), 6.82 (1H, d, J = 8.7, H-5 ), 6.31 (1H, br.s, H-8), 6.11 (1H, br.s, H-6), 5.31 (1H, d, J = 6.8, H-1 ), 3.87 (3H, s, 3 -OCH3). 13C NMR (100 MHz, CD3OD, , ppm): 158.79 (C-2), 135.62 (C-3), 179.74 (C-4), 163.42 (C-5), 101.50 (C-6), 166.31 (C-7), 95.03 (C-8), 158.99 (C-9), 106.10 (C-10), 123.40 (C-1 ), 117.32 (C-2 ), 151.15 (C-3 ), 148.72 (C-4 ), 116.57 (C-5 ), 124.13 (C-6 ), 103.92 (C-1 ), 76.22 (C-2 ), 78.38 (C-3 ), 71.80 (C-4 ), 78.85 (C-5 ), 62.85 (C-6 ), 57.09 (OCH3) [8]. Genistein-7-O-D-glucopyranoside (3), mp 253–255 C (MeOH). HPLC-ESI-MS m/z 433.3 [M + H]+. IR (KBr, max, cm –1): 3253, 1627, 1609, 1581, 1508, 1456, 1309, 1246, 1213, 1085, 1046, 843. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 12.94 (1H, s, 5-OH), 9.59 (1H, s, 4 -OH), 8.43 (1H, s, H-2), 7.40 (2H, d, J = 8.4, H-2 , 6 ), 6.83 (2H, d, J = 8.4, H-3 , 5 ), 6.72 (1H, s, H-8), 6.47 (1H, s, H-6), 5.12 (1H, d, J = 4.3, H-1 ). 13C NMR (100 MHz, DMSO-d6, , ppm): 154.5 (C-2), 120.9 (C-3), 180.4 (C-4), 157.4 (C-5), 99.5 (C-6), 163.0 (C-7), 94.5 (C-8), 157.1 (C-9), 106.0 (C-10), 122.5 (C-1 ), 130.1 (C-2 ), 115.05 (C-3 ), 161.5 (C-4 ), 115.0 (C-5 ), 130.1 (C-6 ), 99.8 (C-1 ), 73.0 (C-2 ), 76.4 (C-3 ), 69.6 (C-4 ), 77.2 (C-5 ), 60.6 (C-6 ) [9]. (+)-Catechin-7-O-D-glucopyranoside (4), mp 165–170 C (MeOH). HPLC-ESI-MS m/z 453.1 [M + H]+. IR (KBr, max, cm–1): 3391, 2923, 1625, 1604, 1704, 1045, 888, 820. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 6.72 (1H, d, J = 1.8, H-2 ), 6.69 (1H, d, J = 8.0, H-5 ), 6.59 (1H, d, J = 8.1, H-6 ), 6.09 (1H, d, J = 1.5, H-8), 5.98 (1H, d, J = 1.6, H-6), 4.70 (1H, d, J = 7.6, H-1 ), 4.55 (1H, d, J = 7.1, H-2), 3.86 (1H, m, H-3), 3.66 (1H, d, J = 11.3, H-6 b), 3.44 (1H, d, J = 4.2, H-6 a), 3.15–3.23