Chemical Composition and Antioxidant Activity of Zanthoxylum armatum Leaves in Response to Plant Age, Shoot Type and Leaf Position

Zanthoxylum armatum (Z. armatum) leaves represent more than 50% of by-products with promising potential applications, and there are still largely unknown variations in chemical composition and antioxidant activity in its leaves. In the present study, the changes in carbon (C), nitrogen (N) and phosphorous (P), soluble protein (SP), amino acid (AA), soluble sugar (SS), total phenol (TP) and total flavonoids (TF) content as well as antioxidant capacity in Z. armatum leaves from two plant ages between two shoot types and three leaf positions were investigated. Our results showed that there are significant effects of plant age, shoot type and leaf position and their interactions on almost all the tested parameters. Shoot types were the main factor affecting the accumulation of chemical compositions and antioxidant capacity, followed by leaf positions and plant ages. Shoot type and leaf position had stronger effects than plant age. Statistical analysis revealed a series of correlations between antioxidant capacity, TP and chemical elements. Z. armatum leaves, an agricultural by-product, showed significant differences in chemical composition and antioxidant activity in response to plant age, shoot type and leaf position, which can be valuable to incentive its cultivation management strategy and its better utilization for economic and environmental benefits.