Table 2.
Aqueous solubility of vitexin and its derivatives at different pH.
| Compound | Aqueous Solubility (mg/L) | ||
|---|---|---|---|
| Deionized H2O at pH 7 | PB at pH 6 | PB at pH 8 | |
| Vitexin | 37.2 ± 2.8 (1) 1 | 7.1 ± 1.2 (0.2) | 157.3 ± 3.1 (4.2) |
| Vitexin-4′-O-β-glucoside (1) | 941.4 ± 68.7 (25.3) | 943.3 ± 211.6 (25.3) | 1802.3 ± 228.6 (48.4) |
| Vitexin-5-O-β-glucoside (2) | 734.6 ± 51.7 (20.0) | 444.2 ± 45.0 (11.9) | 766.9 ± 21.6 (20.6) |
1 The fold increase in aqueous solubility of the vitexin glucoside derivatives is expressed as relative to that of vitexin in deionized H2O, normalized to 1.