Table 4.
Relative quantification of apigenin derivatives in OPL extracts obtained from various drying methods and solvent systems.
| Drying | Solvent | Peak 2 | Peak 4 | Peak 8 | * Peak 10 | * Peak 11 | Peak 12 | TAC (µg /mg) |
|---|---|---|---|---|---|---|---|---|
| O | E | ND | ND | ND | ND | 0.01 ± 0.02 Aa | 1.83 ± 0.13 Aa | 1.84 ± 0.15 Aa |
| EM | 17.50 ± 1.31 Aa | 3.80 ± 0.45 Aa | 17.65 ± 3.01 Aa | 22.04 ± 1.11 Aa | 1.54 ± 0.11 Ab | 36.61 ± 2.34 Ab | 99.14 ± 8.33 Ab | |
| M | 22.46 ± 0.85 Ab | 3.61 ± 0.31 Aa | 17.95 ± 3.20 Aa | 25.50 ± 2.32 Ab | 1.62 ± 0.19 Ab | 40.70 ± 3.18 Ab | 111.84 ± 10.1 Ab | |
| AM | 30.93 ± 2.11 Ac | 4.77 ± 0.41 Ab | 29.11 ± 5.12 Ab | 29.33 ± 2.18 Ac | 1.66 ± 0.25 Ab | 57.99 ± 4.12 Ac | 153.79 ± 14.2 Ac | |
| F | E | ND | ND | ND | ND | 0.02 ± 0.01 Aa | 1.83 ± 0.11 Aa | 1.85 ± 0.12 Aa |
| EM | 10.78 ± 1.21 Ba | 1.95 ± 0.21 Ba | 12.76 ± 2.21 Ba | 14.07 ± 1.13 Ba | 0.65 ± 0.14 Bb | 21.87 ± 2.19 Bb | 62.08 ± 7.09 Bb | |
| M | 18.95 ± 2.10 Ab | 3.39 ± 0.12 Ab | 23.66 ± 4.76 Bb | 21.62 ± 2.10 Ab | 1.49 ± 0.15 Ac | 40.27 ± 3.91 Ac | 109.38 ± 13.1 Ac | |
| AM | 33.34 ± 2.31 Ac | 4.04 ± 0.25 Ac | 30.90 ± 3.14 Ac | 32.62 ± 1.98 Ac | 1.95 ± 0.11 Bd | 57.53 ± 4.32 Ad | 160.38 ± 12.1 Ad | |
| S | E | ND | ND | ND | ND | 0.001 ± 0.02 Ba | 2.14 ± 0.20 Aa | 2.14 ± 0.22 Aa |
| EM | 12.55 ± 0.75 Ba | 2.24 ± 0.18 Ba | 10.89 ± 2.25 Ba | 13.41 ± 1.41 Ba | 0.67 ± 0.13 Bb | 25.68 ± 2.11 Bb | 65.44 ± 6.83 Bb | |
| M | 23.09 ± 1.11 Ab | 4.22 ± 0.20 Bb | 20.24 ± 5.10 Bb | 23.33 ± 2.15 Ab | 1.69 ± 0.10 Ac | 46.42 ± 3.91 Ac | 118.99 ± 12.5 Ac | |
| AM | 35.16 ± 1.95 Ac | 3.72 ± 0.31 Ac | 24.11 ± 4.41 Bb | 28.97 ± 2.41 Ac | 1.92 ± 0.12 Bd | 54.69 ± 4.81 Ac | 148.57 ± 14.0 Ad |
Values marked with different upper-case letters (A,B) indicate comparison between drying methods for the same solvent. Values marked with different lower-case letters (a,b,c,d) indicate comparison between solvents for the same drying method. The significant difference is set at p < 0.05. Abbreviations: F, freeze-dried; O, oven-dried; S, shade-dried; H, hexane; E, ethyl acetate; EM, ethyl acetate–methanol; M, absolute methanol; AM, aqueous methanol;TAC, total apigenin content; Peak 2, apigenin-6,8-di-C-hexose; Peak 4, apigenin-6-C-pentose-8-C-hexose (Isomer 1); Peak 8, apigenin-6-C-pentose-8-C-hexose (Isomer 2); Peak 10, vitexin; Peak 11, isovitexin; Peak 12, apigenin-6-C-hexose-8-C-deoxyhexose. ND—not detected. * indicates absolute quantification using respective standard. Not all hexanoic extracts could extract all quantified luteolin and apigenin derivatives.