A novel application of solubility parameter in extraction of bioactive substances from natural products

The method to design the solvent for the optimal extraction of bio-active ingredients from natural resources was developed. The extraction of polyphenols, anti-oxidant and anti-tyrosinase from mulberry leave was varied with the solvent species and composition of the binary mixture. Due to their own polarities of the active ingredients, the optimal solvent composition of alcohol-water mixture was achieved between 40 - 80% alcohol fraction depending on the alcohol species and target active ingredients. As such, for the extraction of the polyphenols and anti-oxidant the optimal alcohol fraction of alcohol-water binary solvent was about 60% methanol and was lower to about 40% with ethanol and propanols due to their low polar propensities. For the extraction of the anti-tyrosinase ingredients, a higher alcohol fraction of the optimal solvent condition was required because of the lower polarity of target ingredients than that of the anti-oxidants. The extraction efficiency of the bio-active ingredients was correlated with solvent polarity represented with solubility parameter. According to correlations, the optimal solvent polarities for the extraction of polyphenols and anti-oxidation and anyi-tyrosinase ingredients were predicted as 41.2, 40.3 and 35.1 [MPa^1/2], respectively. These solvent polarities were well agreed with the optimal solvent conditions of alcohol species and composition on the binary mixture. Also, the correlation was confirmed with model solvents design with other solvent species of acetone and ethylene glycol.