Isolation and identification of flavonoids components from Pteris vittata L.

Four compounds were isolated and their structures were identified as kaempferol (1), quercetin (2), kaempferol-3-O–d-glucopyranoside (3) and rutin (4), respectively, by spectral analysis and comparison with the spectroscopic data reported in previous literatures (Fig. 1). NMR spectra data of the compounds were listed as follows (Additional file 1).

Structures of flavonoids from P. vittata L

Compound 1 was obtained as yellow amorphous powder. ¹H-NMR (600 MHz, DMSO-d
₆
) ?_H: 6.19 (1H, d, J = 1.8 Hz), 6.44 (1H, d, J = 1.8 Hz), 6.92 (2H, d, J = 9.0 Hz), 8.04 (2H, d, J = 9.0 Hz). ¹³C-NMR (150 MHz, DMSO-d
₆
) ?_C: 93.5 (C-8), 98.2 (C-6), 103.0 (C-10), 115.4 (C-3?, C-5?), 121.7 (C-1?), 129.5 (C-2?), 130.5 (C-6?), 135.6 (C-3), 146.8 (C-2), 156.2 (C-5), 159.2 (C-4?), 160.7 (C-9), 163.9 (C-7), 175.9 (C-4). It was determined as kaempferol by comparison with the spectroscopic data reported in the literature (Liu et al. 2009).

Compound 2 was obtained as yellow amorphous powder. ¹H-NMR (600 MHz, DMSO-d
₆
) ?_H: 6.19 (1H, d, J = 1.8 Hz), 6.40 (1H, d, J = 2.4 Hz), 6.88 (1H, d, J = 8.4 Hz), 7.54 (1H, dd, J = 2.4, 8.4 Hz), 7.67 (1H, d, J = 2.4 Hz). ¹³C-NMR (150 MHz, DMSO-d
₆
) ?_C: 93.3 (C-8), 98.1 (C-6), 102.9 (C-10), 114.9 (C-2?), 115.5 (C-5?), 119.9 (C-6?), 121.8 (C-1?), 135.6 (C-3), 144.9 (C-1?), 146.7 (C-1), 147.6 (C-4?), 156.1 (C-5), 160.7 (C-9), 163.8 (C-7), 175.8 (C-4). It was identified as quercetin by comparison with the spectroscopic data reported in the literature (Ma et al. 2007).

Compound 3 was obtained as yellow amorphous powder. ¹H-NMR (600 MHz, DMSO-d
₆
) ?_H: 3.09 (2H, d, J = 4.2 Hz), 3.21 (1H, d, J = 7.8 Hz), 3.32 (1H, d, J = 11.4 Hz), 3.55 (1H, d, J = 11.4 Hz), 4.29 (1H, s), 4.96 (1H, s), 5.07 (1H, s), 5.36 (1H, s), 5.46(1H, d, J = 7.8), 6.21 (1H, d, J = 1.8 Hz), 6.43 (1H, d, J = 1.8 Hz), 6.88 (2H, d, J = 9.0 Hz), 8.04 (2H, d, J = 9.0 Hz). ¹³C-NMR (150 MHz, DMSO-d
₆
) ?_C: 61.1 (C-6?), 70.2 (C-4?), 74.5 (C-2?), 76.8 (C-5?), 77.8 (C-3?), 94.0 (C-8), 99.1 (C-6), 101.2 (C-1?), 104.3 (C-10), 115.4 (C-3?, C-5?), 121.2 (C-1?), 131.2 (C-2?, C-6?), 133.5 (C-3), 156.6 (C-2), 156.7 (C-9), 160.3 (C-4?), 161.5 (C-5), 164.5 (C-7), 177.8 (C-4). It was determined as kaempferol-3-O–d-glucopyranoside by comparison with the spectroscopic data reported in the literature (Long et al. 2011).

Compounds 4 was obtained as yellow amorphous powder. ¹H-NMR (600 MHz, DMSO-d
₆
) ?
_H: 1.00 (3H, d, J = 6.0 Hz), 3.08 (3H, m), 3.70 (1H, d, J = 12.0 Hz), 4.39 (1H, d, J = 2.4 Hz), 5.10 (2H, d, J = 18.0 Hz), 5.28 (1H, s), 5.35 (1H, d, J = 6.0 Hz), 6.20 (1H, d, J = 2.4 Hz), 6.39 (1H, d, J = 2.4 Hz), 7.54 (1H, d, J = 2.4 Hz), 7.56 (1H, dd, J = 2.4, 12.0 Hz) ¹³C-NMR (150 MHz, DMSO-d
₆
): ?
_C: 17.6 (C-6??), 66.9 (C-6?), 68.1 (C-5??), 69.9 (C-4?), 70.2 (C-2??), 70.4 (C-3??), 71.7 (C-4??), 73.9 (C-2?), 75.8 (C-5?), 76.3 (C-3?), 93.5 (C-8), 98.5 (C-6), 100.6 (C-1??), 101.0 (C-1?), 103.8 (C-10), 115.1 (C-2?), 116.1 (C-5?), 121.0 (C-6?), 121.5 (C-1?), 133.2 (C-3), 144.6 (C-3?), 148.3 (C-4?), 156.3 (C-9), 156.5 (C-2), 161.1 (C-5), 164.0 (C-7), 177.2 (C-4). It was identified as rutin compared with the spectroscopic data reported in the literature (Zhang et al. 2010).