Comparative phytochemicals and antioxidant activity of various solvent extracts of Zanthoxylum armatum leaves from different geographical regions of Himachal Pradesh and their correlation analysis

Zanthoxylum armatum (family-Rutaceae) is a medicinally important and endangered plant species from Himalayan region. The objective of this study was to analyze the effect of different solvents on total phenolic content, total flavonoid content and antioxidant activity of Z. armatum leaves collected from different geographical regions of Himachal Pradesh. Extract of various solvents (chloroform, methanol, n-butanol and water) were prepared using cold maceration method. Total phenolic and flavonoid content of different extracts was quantified by spectrophotometric method. DPPH and FRAP assays were used to evaluate the antioxidant activity of different extracts of Z. armatum leaves. Among all the solvent extracts from different regions, methanol extract (9.26±1.13mg g⁻¹ GAE) of leaves samples collected from Sirmour showed higher total phenolic content; while chloroform extract of Solan (10.7±0.29mg g⁻¹ RE) showed higher flavonoid content. Chloroform extract of Sirmour (9.61±4.02μg ml⁻¹) showed comparatively higher % DPPH radical scavenging activity; whereas, methanol extract of Shimla (55.92±2.0μM Fe (II) equivalents) showed higher FRAP activity among all solvents extract from all geographical regions. The present study also showed correlation of solvent with various parameters such as phenolic content, flavonoid content, DPPH and FRAP assay. These parameters also vary with geographical locations. The results from the present study validate the importance of leaves of Z. armatum as source of natural antioxidants.