Application of Hansen Solubility Parameters in the Aqueous-Ethanol Extraction of Genistein-7-O-[α-rhamnopyranosyl-(1→6)]-β-glucopyranoside from and Its Molecular Orbital Study on Antioxidant Activity.

This study explored the extraction of genistein-7-O-[α-rhamnopyranosyl-(1→6)]-β-glucopyranoside (GTG) from using an aqueous-ethanol solvent system, aiming to optimize yield and antioxidant activity. Hansen solubility parameters (HSP) were employed to determine the optimal solvent composition, with the highest GTG yield (6.83 ± 0.06 mg/g dried weight) obtained from 50% ethanol-correlating well with HSP predictions. Ultrasonic extraction was most effective with solvents having a dielectric constant between 50 and 60. The antioxidant potential of isolated GTG was evaluated using the DPPH assay, which yielded an IC of 87.86 ± 1.85 μM, and the FRAP assay, with a value of 34.23 ± 2.75 mg FeSO equivalents. Molecular orbital analysis revealed HOMO and LUMO energy gaps (ΔE = 10.6715 eV) similar to known antioxidants such as gallic acid, ascorbic acid, Trolox, and quercetin. These findings demonstrate that HSP effectively guided solvent selection for ultrasound-assisted extraction of GTG. The antioxidant activity is attributed to GTG's capacity to donate electrons and stabilize radicals via extended charge delocalization within the aglycone structure, confirming its potential as a natural antioxidant agent.