Structure identification of PAGs
The structures of CG, FG and p -HCG were identified by1H NMR, 13C NMR, MS and melting
point. NMR investigations were carried out at 14.1 T on a Bruker Avance
III spectrometer in an inverse TXI (1H,13C) 1.7 mm probe with a z-gradient at 300 K. The
isolated PAGs were dissolved in D6-DMSO (0.01% TMS). Mass spectroscopic
analysis were performed using Triple TOF 6600 LC-MS/MS with an ESI
interface in positive mode. The operating conditions were as follows:
capillary voltage of 3.88 kV, ion source temperature of 120 ℃, cone
voltage of 30 V, desolvation temperature of 280 ℃, photo- multiplier
voltage of 680 V, vacuum degree of 2.6e-5 mBar and gas
flow rate of 4.2 L/h. The melting point was determined by JHY-50 melting
point apparatus.
Caffeoly glycerol (CG). White solid,
m.p. 124.1-124.8 oC; 1H NMR (DMSO,
600 MHz): d (ppm) 7.50 (d, J = 15.9 Hz, 1H), 7.05 (d, J =
1.9 Hz, 1H), 7.00 (dd, J = 8.2, 2.0 Hz, 1H), 6.76 (d, J =
8.1 Hz, 1H), 6.26 (d, J = 15.9 Hz, 1H), 4.15 (dd, J =
11.2, 4.1 Hz, 1H), 4.01 (dd, J = 11.2, 6.6 Hz, 1H), 3.71 (dt,J = 11.8, 6.1 Hz, 1H), 3.39 (td, J = 11.6, 5.6 Hz, 2H);13C NMR (DMSO, 151 MHz): d (ppm) 167.11, 149.04,
146.11, 145.61, 125.87, 121.85, 116.21, 115.17, 114.35, 69.87, 66.07,
63.52; HREIMS m/z 277.0681 [M+Na]+.
Feruloyl glycerol (FG). White solid, m.p. 121.2-121.9oC; 1H NMR (DMSO, 600 MHz): d (ppm)
, 7.57 (d, J = 15.9 Hz, 1H), 7.33 (d, J = 1.8 Hz, 1H),
7.12 (dd, J = 8.2, 1.8 Hz, 1H), 6.80 (d, J = 8.1 Hz, 1H),
6.49 (d, J = 15.9 Hz, 1H), 4.16 (dd, J = 11.2, 4.1 Hz,
1H), 4.03 (dd, J = 11.2, 6.5 Hz, 1H), 3.83 (s, 3H), 3.74 - 3.70
(m, 1H), 3.44 - 3.38 (m, 2H); 13C NMR (DMSO, 151 MHz):
d (ppm) 167.19, 149.78, 148.41, 145.47, 126.09, 123.59, 115.98, 115.02,
111.60, 69.93, 66.06 , 63.18, 56.15;
HREIMS m/z 291.0829 [M+Na]+.
p -Hydroxycinnamoyl glycerol
(p -HCG).White solid, m.p.
119.6-120.2 oC; 1H NMR (DMSO, 600
MHz): 7.58 (d, J = 16.0 Hz, 1H), 7.56 (d, J = 8.6 Hz, 2H),
6.80 (d, J = 8.6 Hz, 2H), 6.40 (d, J = 15.9 Hz, 1H), 4.16
(dd, J = 11.2, 4.1 Hz, 1H), 4.02 (dd, J = 11.2, 6.6 Hz,
1H), 3.74 - 3.69 (m, 1H), 3.42 - 3.38 (m, 2H); 13C NMR
(DMSO, 151 MHz): d (ppm) 167.14, 160.36, 145.16, 130.76, 125.54, 116.26,
114.67, 69.90, 66.09, 63.17; HREIMS m/z 261.0730 [M+Na]+.