Extraction of Mangiferin from Mango Leaves Using Ethanol–Water–Liquid CO₂ Mixed Solvents and Hansen Solubility Parameter Analysis

Abstract

Mangiferin is a bioactive polyphenol abundant in mango (Mangifera indica L.) leaves and exhibits notable antidiabetic and antioxidant activities. In this study, a green extraction system based on ethanol, water, and liquid carbon dioxide (CO₂) was developed to enhance mangiferin extraction. Experiments were conducted in a 50 cm³ high-pressure cell at 25 °C and 8 MPa using ethanol–water mixtures with varying volume fractions with and without liquid CO₂. The highest extraction yield was obtained at an ethanol volume fraction of 25% in the binary ethanol–water system, consistent with the strong hydrogen-bonding affinity of mangiferin. The addition of liquid CO₂ improved solvent permeability and mass transfer, leading to a further exponential increase in extraction yield. A thermodynamic correlation model based on Hansen solubility parameters produced significant errors at high ethanol concentrations but quantitatively described the exponential increase in yield due to CO₂ addition across a wide composition range with high extraction rates.