Comprehensive profiling of antioxidants in <i>Zanthoxylum bungeanum</i> leaves using two-dimensional liquid chromatography and regional comparisons

The phenolic components in Zanthoxylum bungeanum leaves have been shown to contribute significantly to their antioxidant activity. However, the specific contribution of individual monomeric components to this activity remains unclear. This study employed two-dimensional liquid chromatography with electrochemical detection and tandem mass spectrometry (2D-LC-ECD-MS/MS) to rapidly screen and identify these components. A total of 31 antioxidant components were identified, including proanthocyanidins, chlorogenic acids, and flavonoids. The fractions collected from the first-dimension showed significant radical scavenging capacity, with a strong correlation between the response of ECD and antioxidant activity. Eleven compounds were quantitatively analyzed in 24 batches of samples using LC-ECD. While the chemical composition of samples across regions was highly similar, significant differences in content were observed. Quercitrin was the most abundant compound (0.076–3.547 mg/g), significantly higher than other phenolic compounds (p < .05). Samples from the Yuci region of Shanxi exhibited a 75% higher concentration of proanthocyanidins than those from Qianxinan, Guizhou (p < .05), highlighting significant regional variations. This study screened and identified antioxidant components in Zanthoxylum bungeanum leaves and evaluated the quality of samples across origins. The methodology also provides a reference for investigating antioxidants in other edible and medicinal plants.