Bioactivity-oriented extraction of sea buckthorn flavonoids with enhanced β-galactosidase inhibition: A processing strategy for anti-aging functional food ingredients

Senescence-associated β-galactosidase (SA-β-Gla) is a key enzymatic biomarker of cellular senescence and aging, making its inhibition a promising strategy for developing anti-aging functional foods. Sea buckthorn ( Hippophae rhamnoides L . ) berries are rich in flavonoids with antioxidant and anti-aging potential; however, conventional extraction methods prioritize yield over the retention of bioactivity. In this study, we developed a bioactivity-oriented (BO) extraction strategy guided by β-Gla inhibitory activity, using ultrasound-assisted enzymatic extraction optimized by response surface methodology. Under the optimal BO conditions, the β-Gla inhibition rate reached 74.71 ± 1.88%. After purification, the BO extract contained significantly higher levels of the major flavonoids rutin, taxifolin, and isorhamnetin-3-O-rutinoside (collectively accounting for 54.0%) compared to the yield-oriented (YO) extract (27.5%). Consequently, the purified BO extract exhibited stronger antioxidant activity and β-Gla inhibition (IC₅₀ = 30.33 μg/mL) than the YO extract (IC₅₀ = 47.62 μg/mL). Correlation analysis indicated that the enhanced bioactivity resulted from synergistic interactions among multiple flavonoids. These findings demonstrate that the BO strategy selectively enriches high-activity flavonoid components and provides an effective processing approach to produce sea buckthorn-derived ingredients with targeted anti-aging properties for functional food applications.