Table 2.
Solubility data of plant secondary metabolites in water
| Designation | Secondary metabolite | Solubility (mg/ml) |
|---|---|---|
| Very slightly soluble | Ferulic acid | 0.906 |
| Kaempferol | 0.178 | |
| Luteolin | 0.138 | |
| Sinapic acid | 0.631 | |
| Quercetin | 0.261 | |
| Slightly soluble | Caffeic acid | 1.61 |
| Chlorogenic acid | 3.44 | |
| t-Cinnamic acid | 1.15 | |
| p-Coumaric acid | 1.02 | |
| Rutin | 3.54 | |
| Scopoletin | 2.35 |
Data retrieved from ALOPGS 2.1. According to the United Stated Pharmacopeia (USP30), the water solubility of a ‘slightly soluble’ compound ranges from 10 mg/ml down to 1 mg/ml whereas ‘very slightly soluble’ compounds are defined as 1 mg/ml to 100 µg/ml