Multivariate characterization of color and polyunsaturated amides in Zanthoxylum bungeanum Maxim.: Insights into α-glucosidase inhibitory mechanisms

In response to the growing interest in plant-derived functional ingredients for metabolic health regulation, this study investigates the color parameters and phytochemical composition of Zanthoxylum bungeanum Maxim . ( Z. bungeanum ) across multiple cultivars, with a particular focus on their potential α-glucosidase (α-Glu) inhibitory mechanisms. Multiple cultivars of Z. bungeanum were collected from Longnan City, Gansu Province, China. Pericarp color parameters were extracted using digital imaging techniques. The relative peak areas of four major polyunsaturated amides were used for compositional analysis. Multivariate statistical methods, including Hierarchical Cluster Analysis (HCA), Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA), and Pearson correlation analysis, were performed to evaluate the relationships among cultivar types, color parameters, and phytochemical composition. In vitro α-Glu inhibition assays demonstrated that pericarp powder extract and four polyunsaturated amides exhibited notable activity, with hydroxy-γ-sanshool showing the highest potency. Fluorescence spectroscopy, circular dichroism and molecular docking analyses further revealed the underlying interaction mechanisms, primarily involving hydrogen bonding, hydrophobic interactions, and van der Waals forces. This study provides valuable scientific evidence for the functional development of Z. bungeanum and the discovery of natural hypoglycemic agents based on polyunsaturated amide compounds. • Multivariate model links Z. bungeanum cultivars, pericarp color, and amide content. • Digital camera combined with computer vision enables bulk sample color evaluation. • Synchronous fluorescence reveals Trp residue shifts in α-Glu binding. • Circular dichroism (CD) analysis shows a decrease in α-helix upon binding. • Molecular docking reveals hydrogen bonding as key inhibitory mechanism.