Extraction of Chlorogenic Acid Using Single and Mixed Solvents.

Chlorogenic acid, which is extracted from a wide range of natural sources, is attracting the attention of many researchers in the pharmaceutical and biomedical fields due to its various positive effects, such as such as anti-inflammatory and antibacterial properties. Considering the effects of economics and solvent toxicity, water, ethanol, and their mixtures were selected as the solvents for extracting chlorogenic acid at various temperatures (298~318 K) and over a whole range of concentrations. The solubility of chlorogenic acid increased with temperature regardless of the solvents, and the solubility was higher in pure ethanol than in pure water. The solubility of chlorogenic acid in mixed solvents exhibited a gradual rise as the water content increased, reaching a maximum at a specific water weight fraction. These trends were well predicted by the COSMO-SAC model and Hansen solubility parameter method. By comparing the σ-profile, it was confirmed that the maximum solubility in mixed solvent comes from the similarity of σ-profiles between chlorogenic acid and mixed solvent which represents the surface charge density of the molecule.