Table 1.
Extraction yield (means ± SD) of free phenolics (FP) using 60% acetone and bound phenolic (BP) using 0.75% NaOH expressed in milligram per gram of BSG dry weight (mg/g BSG dw).
| Samples | Extraction Yield (mg/g BSG) |
TPC (mg GAE/g BSG) |
SQP (mg/g BSG) |
|||
|---|---|---|---|---|---|---|
| FP | BP | FP | BP | FP | BP | |
| Hex F. | 19.4 ± 16.8 a | 12.2 ± 7.1 b | 0.09 ± 0.09 a | 0.02 ± 0.0 b | n.d. b | <0.01 c |
| DE F. | 25.8 ± 14.2 a | 8.3 ± 1.2 b | 0.23 ± 0.09 a | 0.67 ± 0.02 b | <0.01 a | 0.8 ± 0.0 a b |
| EtOAc F. | 6.6 ± 4.0 a | 34.6 ± 6.9 a | 0.12 ± 0.07 a | 3.5 ± 0.5 a | <0.01 a | 2.9 ± 0.3 a |
| BuOH F. | 6.2 ± 4.4 a | 23.8 ± 8.3 a b | 0.09 ± 0.004 a | 1.0 ± 0.4 a b | <0.01 a b | 0.07 ± 0.03 b c |
| WR F. | 22.2 ± 7.8 a | 345 ± 162.5 a | 0.11 ± 0.02 a | 6.2 ± 2.8 a | n.d. b | 0.03 ± 0.04 c |
| Total | 80.2 ± 3.4 | 424.2 ± 179.9 | 0.64 ± 0.07 | 11.3 ± 3.6 | 0.013 ± 0.02 | 3.80 ± 0.2 |
| Crude (Control) | 94.9 ± 9.2 | n.t. | 1.7 ± 0.2 | n.t. | <0.02 | n.t. |
Total represents the sum of each solvent fraction (F.) in the column. Fractions generated by Hex—hexane, DE—diethyl ether, EtOAc—ethyl acetate, BuOH—butanol and WR (water residue); “n.t.” means not tested, “n.d.” means not detected. The corresponding polyphenols content in FP and BP samples represented by Total Phenolic Content (TPC) by Folin–Ciocalteu in mg of gallic acid equivalent per gram of BSG (mg GAE/g BSG), and sum of quantified polyphenols (SQP) by UPLC-MS/MS in mg/g BSG. Values in the same column for each type of extracted phenolics (FP and BP) with each solvent fraction (Hex, DE, EtOAc, BuOH, WR) bearing different letters (a, b, c) are significantly different (p < 0.05) from each other.