Gang Tian

This work was designed as a comparative extract-level study to clarify how solvent polarity influences antioxidant activity, preliminary hyaluronidase inhibition, and supportive chemical features in Buddleja officinalis Maxim.. Six extracts prepared with petroleum ether, ethyl acetate, n-butanol, water, 60% ethanol, and 95% ethanol were independently prepared in triplicate and evaluated for DPPH· radical scavenging, ABTS⁺· radical scavenging, ferric reducing power, and hyaluronidase inhibitory activity, together with total flavonoid and linarin contents. 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, the petroleum ether and 60% ethanol extracts showed relatively strong inhibition at 2.5 mg/mL, with inhibition rates of 74% and 68%, respectively. Supportive ¹H NMR and UPLC–QTOF–MS data, including representative chromatographic profiles and representative compound assignments for the 60% ethanol extract, indicated clear polarity-dependent differences in extract composition; the 60% ethanol fraction was enriched in phenylethanoid glycosides and flavonoid glycosides, whereas the petroleum ether fraction was characterized mainly by lipophilic constituents. Overall, the results support a comparative and exploratory interpretation in which medium-polarity phenolic-rich fractions are associated with stronger antioxidant effects, while non-polar fractions may contribute more strongly to hyaluronidase inhibition. Because the present work was based on in vitro assays and preliminary enzyme screening, further studies with positive inhibitor controls, potency evaluation, and activity-guided isolation are still required.