Solvent Polarity Shapes Antioxidant Capacity, Preliminary Hyaluronidase Inhibition, and Chemical Profile of Buddleja...

This study comparatively evaluated how solvent polarity affects the chemical antioxidant capacity, preliminary hyaluronidase inhibition, and supportive chemical features of Buddleja officinalis Maxim. Six extracts prepared with petroleum ether, ethyl acetate, n-butanol, water, 60% ethanol, and 95% ethanol were assessed using DPPH·, ABTS⁺·, ferric reducing power, and hyaluronidase inhibition assays, together with total flavonoid and linarin determinations. The 60% ethanol extract showed the strongest overall radical-scavenging activity, reaching 95% DPPH· scavenging and 95% ABTS⁺· scavenging at 2 mg/mL, whereas the 95% ethanol extract showed the highest ferric reducing power under the tested conditions. Total flavonoid and linarin contents were highest in the ethanol-rich fractions, especially the 95% ethanol and 60% ethanol extracts. In the hyaluronidase assay, both the petroleum ether and 60% ethanol extracts showed relatively strong inhibition at 2.5 mg/mL, with inhibition rates of 74% and 68%, respectively, suggesting that different chemical classes may contribute to this endpoint. Supportive ¹H NMR and UPLC-QTOF-MS data indicated clear polarity-dependent compositional differences; the 60% ethanol extract was enriched in phenylethanoid glycosides and flavonoid glycosides, whereas the petroleum ether extract showed predominantly lipophilic features. Overall, medium-polarity phenolic-rich fractions were more closely associated with chemical antioxidant capacity, while hyaluronidase inhibition may involve contributions from both non-polar and medium-polarity constituents. The present extract-level comparison provides a useful basis for fraction selection, extract standardization, and follow-up activity-guided studies.