Table 1.
Solubility of berberine (mean ± SD; n = 3) in NADES and reference solvents. The solubility in all solvents were significantly different from solubility in water (p-values < 0.05).
| NADES Type | Composition (w/w) | Berberine Solubility at 22 °C (mg/mL) | |
|---|---|---|---|
| Water | 2.10 ± 0.05 | ||
| Ethanol | 2.75 ± 0.05 | ||
| Urea-based | 1 | Proline–urea 1:1 | 15.0 ± 0.05 |
| 2 | Proline–urea 2:1 | 12.3 ± 0.07 (B) | |
| Sugar and organic acid-based | 3 | Citric Acid–glucose 1:1 | 0.54 ± 0.02 |
| Organic acid and amino acids-based | 4 | Proline–Malic Acid 1:1 | 2.50 ± 0.06 |
| 5 | Proline–Malic Acid 1:2 | 2.80 ± 0.05 (A) | |
| 6 | Proline–Malic Acid 1:3 | 6.00 ± 0.09 | |
| 7 | Proline–Malic Acid–Water 1:2:3 | 1.57 ± 0.02 * | |
| 8 | Proline–Malic Acid–Water 1:2:6 | 0.74 ± 0.01 * | |
| 9 | Proline–Citric Acid 1:1 | 1.82 ± 0.04 * | |
| 10 | Proline–Citric Acid 1:2 | 2.45 ± 0.03 * | |
| 11 | Proline–Tartaric Acid–Citric–Acid 1:1:1 | 1.75 ± 0.05 * | |
| 12 | Proline–Glutamic Acid 1:1 | 0.45 ± 0.01 | |
| 13 | Proline–Glutamic Acid 1:2 | 0.78 ± 0.02 * | |
| 14 | Proline–Malic Acid–Lactic Acid–Water 1:0.2:0.3:0.5 | 25.0 ± 0.05 (C) | |
| Choline chloride-based | 15 | Proline–Choline Chloride 1:1 | 1.24 ± 0.02 |
| 16 | Proline–Choline Chloride 1:2 | 1.05 ± 0.02 * | |
| 17 | Proline–Choline Chloride 2:1 | 0.80 ± 0.02 * | |
| 18 | Choline Chloride–Malic Acid 1:1 | 0.30 ± 0.01 * | |
| 19 | Choline Chloride–Malic Acid 1:2 | 1.35 ± 0.06 * | |
| 20 | Choline Chloride–Malic Acid 1:3 | 1.56 ± 0.05 * | |
| 21 | Choline Chloride–Malic Acid 2:1 | 1.42 ± 0.06* | |
| 22 | Choline Chloride–Malic Acid 3:1 | 0.87 ± 0.05 * | |
| 23 | Choline Chloride–Citric Acid 2:1 | 0.75 ± 0.02 * | |
| 24 | Choline Chloride–Citric Acid 3:1 | 0.64 ± 0.03 | |
| 25 | Carnitine–Choline Chloride 1:1 | 0.41 ± 0.02 | |
| Carnitine-based | 26 | Acetylcarnitine–Choline Chloride 1:1 | 0.89 ± 0.05 |
| 27 | Carnitine–Proline 1:1 | 1.07 ± 0.04 * | |
| 28 | Acetylcarnitine–Proline 1:1 | 0.85 ± 0.03 * | |
| 29 | Carnitine–Proline 1:1 | 1.48 ± 0.07 * | |
| 30 | Carnitine–sorbitole 1:1 | 0.35 ± 0.01 | |
| 31 | Acetylcarnitine–sorbitole 1:1 | 0.27 ± 0.01 | |
| 32 | Carnitine–xylitole 1:1 | 0.38 ± 0.01 | |
| 33 | Acetylcarnitine–xylitole 1:1 | 0.25 ± 0.01 | |
| 34 | Acetylcarnitine–proline–Lactic Acid 1:1:2 | 1.24 ± 0.05 * | |
| 35 | Acetylcarnitine–proline–Citric Acid 1:1:2 | 1.36 ± 0.04 * | |
| 36 | Lactic Acid | 9.00 ± 0.05 | |
| Lactic Acid-based | 37 | Lactic Acid–Water–Citric Acid 1:1:0.1 | 10.00 ± 0.06 |
| 38 | Lactic Acid–Water–Ossalic Acid 1:1:0.1 | 10.00 ± 0.09 |
* An asterisk indicates instability of the prepared berberine in NADES solution, evidenced by precipitation or crystallization of constituents.