Supercritical CO2 extraction of phenolic compounds from willow bark

Abstract

This study uses supercritical CO₂ extraction with ethanol as a co-solvent to recover phenolic components from using willow bark of two species Salix caprea and Salix phylicifolia. The research examined how pressure, extraction duration, and co-solvent affect the compound yield and quality to optimize the extraction process. The phenolic content was analyzed and compared using High-Performance Liquid Chromatography (HPLC), focusing on salicin, a bioactive molecule with therapeutic characteristics. It was found that the use of ethanol resulted in increased extracted concentration of salicin notably at two-hour extraction time. The salicin content was greater in extracts of Salix phylicifolia compared to Salix caprea. Despite being effective, the calibration curve for salicin was missing. Despite the challenges, the study shows the efficiency of supercritical CO₂ extraction, specifically with ethanol, as an environmentally friendly approach for obtaining value-added chemicals.