6 (10 mg), 8 (14 mg), 4 (17 mg), 7 (8 mg), and 9 (10 mg), respectively. Purification of the isolated compounds was carried out
on a Sephadex LH-20 column (25 cm × 1 cm) using methanol as eluent. The structure elucidation and identification of the
pure isolated flavonoid compounds were carried out through chemical investigation (complete and mild acid hydrolysis) and
1
13
physical investigation (UV, H NMR, C NMR, APT, HMBC, FABMS, and EIMS) as well as a comparison with previously
reported data [6, 12, 13].
Kaempferol-3-O-(2′′-α-L-arabinopyranosyl)-α-L-rhamnopyranoside-7-O-α-L-rhamnopyranoside (1).
Pale yellow crystals, mp 230–233°C, R 0.47 (BAW). UV/Vis (λ , MeOH, nm, log ε): (MeOH) 267 (2.3), 346 (1.8); (+NaOMe)
f
max
268 (2.3), 394 (2.4); (+AlCl ) 273 (2.3), 302 (1.1), 348 (1.3), 399 (1.2); (+AlCl /HCl) 274 (2.3), 300 (1.1), 345 (1.4), 398
3
3
1
(1.3); (+NaOAc) 266 (2.5), 350 (1.7); (+NaOAc/H BO ) 264 (2.6), 314 (1.3), 348 (1.9). H NMR (300 MHz, DMSO-d , δ,
3
3
6
ppm, J/Hz): 7.8 (2H, d, J = 9.0, H-2′,6′); 6.95 (2H,d, J = 9.0, H-3′,5′); 6.7 (1H, d, J = 2.0, H-8); 6.4 (1H,d, J = 2.0, H-6); 5.54
(1H, d, J = 2.0, H-1′′′); 5.38 (1H, d, J = 2.0, H-1′′); 4.2 (1H, d, J = 6.9, H-1′′′′), 3.1–4.0 (m, sugar protons overlapped with -OH
13
proton signals), 1.1 (3H, d, J = 6, CH -rhamnose at 7-position), 0.9 (3H, d, J = 6, CH -rhamnose at 3-position). C NMR
3
3
(75 MHz, DMSO-d , δ, ppm): 178.8 (C-4) (C), 162.4 (C-7) (C), 162.3 (C-5) (C), 161.8 (C-4′) (C), 158.2 (C-2) (C), 156.8
6
(C-9) (C), 134 (C-3) (C), 131 (C-2′) (CH), 131 (C-6′) (CH), 120.2 (C-1′) (C), 116.3 (C-3′) (CH), 116.3 (C-5′) (CH), 106.9
(C-1′′′′) (CH), 106.5 (C-10) (C), 101.5 (C-1′′) (CH), 100.1 (C-6) (CH), 99.1 (C-1′′′) (CH), 94.5 (C-8) (CH), 81.2 (C-2′′) (CH),
79.6 (C-3′′′′) (CH), 77.5 (C-4′′′) (CH), 76.9 (C-2′′′′) (CH), 72.3 (C-2′′′) (CH), 71 (C-3′′) (CH), 70.9 (C-5′′) (CH), 70.7 (C-4′′′′)
(CH), 70.6 (C-4′′) (CH), 70.4 (C-3′′′) (CH), 70.0 (C-5′′′) (CH), 66.4 (C-5′′′′) (CH ), 18.6 (C-6′′) (CH ), 18.1 (C-6′′′) (CH ).
2
3
3
–
Negative FABMS, m/z 709 (M-1) corresponding to molecular formula C H O .
32 38 18
Kaempferol-3-O-(2′′-β-D-glucopyranosyl)-α-L-rhamnopyranoside-7-O-α-L-rhamnopyranoside (2) [13]. Pale
yellow crystals, mp 242–247°C, R 0.43 (BAW). UV/Vis (λ , MeOH, nm, log ε): (MeOH): 265 (2.4), 344 (1.6); (+NaOMe)
f
max
266 (2.3), 389 (2.4); (+AlCl ) 275 (0.6), 299 (1.1), 344 (1.5), 394 (1.3); (+AlCl HCl) 275 (2.3), 300 (1.1), 344 (1.4), 393(1.3);
3
3
1
(+NaOAc) 265 (2.5), 380 (1.6); (NaOAc/H BO ) 265 (2.5), 345 (1.8). H NMR (500 MHz, DMSO-d , δ, ppm, J/Hz): 7.7
3
3
6
(2H, d, J = 8.5, H-2′,6′); 6.8 (2H, d, J = 8.5, H-3′,5′); 6.65 (1H, d, J = 2.0, H-8); 6.35 (1H, d, J = 2.0, H-6); 5.48 (1H, d, J = 2.0,
H-1′′); 5.33 (1H, d, J = 2.0, H-1′′′); 4.16 (1H, d, J = 7.00, H-1′′′′); 3.4 (m, sugar protons overlapped with -OH proton signals);
13
1.1 (3H, d, J = 6, CH -rhamnose at position 7); 0.85 (3H, d, J = 6, CH -rhamnose at position 3). C NMR (125 MHz,
3
3
DMSO-d , δ, ppm): 176.8 (C-4), 162.2 (C-7), 162.11 (C-5), 161.1 (C-4′), 156.5 (C-9), 156.7 (C-2), 134.9 (C-3), 131.1 (C-2′,
6
C-6′), 120.9 (C-1′), 116.2 (C-3′, C-5′), 106.8 (C-1′′′′), 106.75 (C-10), 101.3 (C-1′′), 100.1 (C-6), 99.9 (C-1′′′), 95.1 (C-8), 81.1
(C-2′′), 79 (C-3′′′′), 76.7(C-5′′′′), 76.2 (C-2′′′′), 74.2 (C-4′′), 72.1 (C-4′′′), 71.1 (C-3′′), 70.9 (C-5′′), 70.7 (C-4′′′), 70.5 (C-3′′′),
–
70.3 (C-2′′′), 69.8 (C-5′′′), 62.1 (C-6′′′′), 18.4 (C-6′′), 17.95 (C-6′′′′). Negative FABMS, m/z 739 (M-1) corresponding to
molecular formula C H O .
33 41 19
Kaempferol-3,7-di-O-α-L-rhamnopyranoside (3) [6]. Whitish yellow crystals, mp 201–205°C, R 0.62 (BAW).
f
UV/Vis (λ , MeOH, nm, log ε): (MeOH) 266 (1.07), 345 (0.8); (+NaOMe) 266 (0.9), 387 (1.2); (+AlCl ) 274 (1.1), 300
max
3
(1.1), 345 (0.8), 399 (0.4); (+AlCl /HC1) 274 (1.1), 299 (0.5), 341 (0.7), 399 (0.6); (+NaOAc) 265 (1.1), 354 (0.7), 389 (0.6);
3
1
(+NaOAc/H BO ) 266 (1.1), 314 (0.7), 243 (0.8). H NMR (500 MHz, DMSO-d , δ, ppm, J/Hz): 7.76 (2H, d, J = 9.0,
3
3
6
H-2′,6′); 6.87 (2H, d, J = 9.0, H-3′,5′); 6.66 (1H, d, J =1.8, H-8); 6.35 (1H, d, J = 1.8, H-6); 5.5 (1H, d, J =2, H-1′′); 5.3 (1H,
d, J = 2, H-1′′′); 3–4 (m, sugar protons overlapped with -OH proton signals); 1.1 (3H, d, J = 6.0, CH -rhamnose at position 7);
3
13
0.8 (3H, J = 6.0, CH -rhamnose at position 3). C NMR (125 MHz, DMSO-d , δ, ppm): 178 (C-4), 162.3 (C-7); 161.5 (C-5);
3
6
160.7 (C-4′); 158.3 (C-2), 156.6 (C-9), 135 (C-3), 131.2 (C-2′, C-6′), 121 (C-1′), 116 (C-3′, C-5′), 106.3 (C-10), 102.4 (C-1′′)
100 (C-6), 99.03 (C-1′′′), 95 (C-8), 72.2 (C-4′′), 71.7 (C-5′′), 71.2 (C-4′′′), 70.9 (C-2′′), 70.8 (C-2′′′), 70.6 (C-3′′), 70.6
(C-3′′′), 70.3 (C-5′′′), 18.00 (C-6′′), 18.5 (C-6′′′).
Kaempferol (4) [6]. Yellow crystals, mp 276–280°C, R 0.72 (BAW). EIMS, m/z 286.
f
Isorhamnetin-3-O-β-L-arabinopyranoside-7-O-(2′′′-β-D-glucopyranosyl)-α-L-rhamnopyranoside (5) [12]. Pale
yellow crystals, mp 248–253°C, R 0.42 (BAW). UV/Vis (λ , MeOH, nm, log ε): (MeOH) 256 (0.9), 358 (0.7); (+NaOMe)
f
max
265 (0.9), 415 (0.7); (+AlCl ) 263 (0.9), 299 (0.4), 362 (0.4), 406 (0.5); (+AlCl /HCl) 262 (0.9), 301 (0.4), 361 (0.5), 401
3
3
1
(0.5); (+NaOAc) 259 (1.1), 365 (0.6), 417 (0.3); (NaOAc/H BO ) 256, 293, 357. H NMR (500 MHz, DMSO-d , δ, ppm,
3
3
6
J/Hz): 7.8 (1H, d, J = 2.0, H-2′); 7.4 (1H, dd, J = 8.5, 2.0, H-6′); 6.7 (1H, d, J = 8.5, H-5′); 6.6 (1H, d, J = 2.0, H-8); 6.37 (1H,
d, J = 2.0, H-6); 5.4 (1H, d, J = 6.0, H-1′′), 5.6 (1H, d, J = 1.6, H-1′′′), 4.46 (1H, d, J = 7.5, H-1′′′′), 3.81 (3H, s, OCH ); 3–4
3
13
(m, sugar protons overlapped with -OH proton signals); 1.08 (3H, d, J = 6.0, CH of rhamnose). C NMR (125 MHz, DMSO-d ,
3
6
δ, ppm): 178 (C-4), 161.7 (C-7), 161.3 (C-5), 157.2 (C-2), 156.3 (C-9), 150.5 (C-4′), 147.6 (C-3′), 134.3 (C-3), 123.2 (C-6′),
121.1 (C-1′), 115.8 (C-5′), 113.5 (C-2′), 106.1 (C-10), 105.1 (C-1′′′′), 102.1 (C-1′′), 99.9 (C-6), 98.6 (C-1′′′), 95.3 (C-8), 81.2
(C-2′′′), 77.2 (C-3′′′′), 76.7 (C-5′′′′), 74.5 (C-2′′′′), 72.4 (C-3′′), 71.4 (C-2′′), 70.8 (C-4′′′), 70.3 (C-4′′′′), 70.1(C-5′′′′), 69.3
(C-3′′′), 67.08 (C-4′′), 65.4 (C-5′′), 61.5 (C-6′′′′), 56.2 (OCH ), 18.3 (C-6′′′).
3
485