Comparative analysis of chemical composition in <i>Zanthoxylum avicennae</i> leaves and branches based on UPLC-Q-Orbitrap HRMS, and evaluation of their antioxidant activities

This study comprehensively analyzes the chemical constituents of <i>Zanthoxylum avicennae</i> leaves and branches using UPLC-Q-Orbitrap HRMS. A total of 64 components were identified, with fragmentation patterns summarised for key compounds. Notably, 51 of these components were newly discovered in this plant. The predominant compound classes were alkaloids (31.25%) and flavonoids (25.00%). Visualisation results revealed significant differences in chemical composition between leaves and branches, with an overlap rate of only 26.60%. Leaves were rich in flavonoids such as neohesperidin, while branches contained more alkaloids, such as schinifoline. Antioxidant activity, assessed using DPPH and ABTS assays, indicated that methanol extracts had notable antioxidant potential. The leaf extract demonstrated superior antioxidant activity (ABTS: IC₅₀ = 0.098 ± 0.006 mg/mL; DPPH: IC₅₀ = 3.624 ± 0.070 mg/mL) compared to the branch extract (ABTS: IC₅₀ = 0.303 ± 0.004 mg/mL; DPPH: IC₅₀ = 3.265 ± 0.075 mg/mL), likely due to differences in the content and variety of flavonoids.