Table 1. Physicochemical properties of borneol, isoborneol, camphor, and naphthalene, as well as those of quercetin, ginkgolide A, orcinol glucoside, tanshinol, and cinnamic acid.
| Compound |
Measured solubility (mg/mL) |
SW/SO |
pKa1 |
LogD by ACD |
LogD by Pallas |
|||
|---|---|---|---|---|---|---|---|---|
| SW | SO | pH=1 | pH=7 | pH=1 | pH=7 | |||
| Organic solvent: n-hexane | ||||||||
| Borneol | 0.71 | 87 | 122 | >14 | 2.55 | 2.55 | 3.00 | 3.00 |
| Isoborneol | 0.69 | 88 | 127 | >14 | 2.55 | 2.55 | 3.00 | 3.00 |
| Camphor | 1.84 | 347 | 189 | >14 | 2.09 | 2.09 | 2.92 | 2.92 |
| Naphthalene | 0.023 | 171 | 7435 | >14 | 3.36 | 3.36 | 3.12 | 3.12 |
| Organic solvent: ethyl acetate | ||||||||
| Borneol | 0.71 | 315 | 444 | – | – | – | – | – |
| Isoborneol | 0.69 | 513 | 743 | – | – | – | – | – |
| Camphor | 1.84 | 698 | 379 | – | – | – | – | – |
| Naphthalene | 0.023 | 217 | 9435 | – | – | – | – | – |
| Quercetin | 0.007 | 17 | 2414 | 8.8 | 1.99 | 1.99 | 1.85 | 1.84 |
| Ginkgolide A | 0.22 | 53.0 | 241 | 11.3 | −0.04 | −0.04 | −0.14 | −0.14 |
| Orcinol glucoside | 342 | 5.0 | 0.01 | 9.8 | −0.9 | −0.9 | −0.75 | −0.75 |
| Tanshinol | 297 | 0.019 | 0.00006 | 3.3 | −1.15 | −4.73 | −0.28 | −3.77 |
| Cinnamic acid | 25.2 | 3.46 | 0.137 | 4.5 | 1.21 | −1.77 | 2.16 | −0.38 |
SW, water solubility at pH 7.4. SO, solubility in the organic solvent n-hexane or ethyl acetate. pKa1 and LogD values were calculated using ACD/aqueous solubility v8.02 via the ACD/I-Lab service (Advanced Chemistry Development Inc, Toronto, Canada). LogD was also calculated using Pallas software (Pallas 3.7.1.1; CompuDrug International, Sedona, AZ, USA).