Thunberg, a medicinal plant, remains understudied despite its potential therapeutic benefits. This study aimed to determine the phytochemical profiles and antioxidant capacities in the extracts of different accessions of by measuring the total polyphenol and flavonoid content of the extracts coupled with DPPH and ABTS assays. In addition, phytochemical screening via LC-MS/MS and high-performance liquid chromatography analysis quantified nine compounds wherein chlorogenic acid (CA) was found to be the most abundant in all compounds while hyperoside and peucedanol were the least. Results showed variation in these compounds' content among accessions (2.01-21.31 mg/g CA) and plant parts (0.34-19.57 mg/g CA), with leaves generally showing higher antioxidant activity. The abundance of these compounds These integrated analyses provide insights into the phytochemical composition and antioxidant activity of this understudied plant, contributing to advances in natural product chemistry and potential therapeutic applications.