Extraction of Cynaroside from Honeysuckle by Nonionic Surfactant-Mediated Aqueous Extraction with Cloud Point Enrichment and Purification by Metal Complexation

Honeysuckle is rich in cynaroside (Cy), but its extraction and purification are difficult due to its poor solubility in water. Therefore, nonionic surfactants were used to extract Cy from honeysuckle plants, enabling the formation of micelles that solubilized Cy in aqueous solution. The effects of temperature, extraction time, surfactant concentration, and the solid–liquid ratio on the extraction rate of Cy were investigated to determine the optimal extraction conditions. The cloud point effect of the optimal nonionic surfactant was exploited to separate the extracting solution into two distinct phases, which resulted in the concentration of Cy into the up phase. The phase containing the extracted Cy was then purified by metal complexation after phase separation using CaCl₂ followed by EDTA, resulting in a purity of Cy of 93.7%. Surfactants have high biological safety, making the extraction process safer and more environmentally friendly. As a result, the process developed in this study enabled the efficient and environmentally friendly extraction of Cy from plants, which has potential value in the production of various medicines and health products containing natural botanicals, such as Cy.