OICC Press Journal of Nanostructure in Chemistry 2193-8865 15 3 2025 06 28 Biogenic Synthesis of Gold Nanoparticles Using Capparis zeylanica Extract and Their Oxidative and Cytotoxic Effects on Colorectal Cancer Cells 10.57647/jnsc.2025.1503.11 EN Zeli Li Dongguan Hospital of Guangzhou University of Chinese Medicine, Dongguan Traditional Chinese Medicine Hospital, Dongguan 523000, China Shuwen Li Dongguan Hospital of Guangzhou University of Chinese Medicine, Dongguan Traditional Chinese Medicine Hospital, Dongguan 523000, China https://orcid.org/0009-0007-3286-2667 Journal Article 2025 06 28 This work uses leaf extract from Capparis zeylanica, a medicinal plant that is seldom investigated for nanomaterial synthesis, to create gold nanoparticles (AuNPs) in a sustainable manner. According to TEM and SEM, the resultant AuNPs were mostly spherical and ranged in size from 40 to 50 nm. In contrast to previous findings on green synthesis, our study makes use of C. zeylanica's distinct phytochemical makeup, which is rich in flavonoids and glycosides, to improve the creation of nanoparticles and their biofunctionality. While FTIR and GC-MS/MS revealed the participation of extract-derived phenolic and flavonoid chemicals in reduction and stabilization, XRD indicated a face-centered cubic crystalline structure. In HT-29 colorectal cancer cells, these AuNPs biologically caused a dose-dependent rise in reactive oxygen species (ROS), which increased by 4.0 times at 40 µg/mL. Furthermore, we provide comprehensive mechanistic insight, demonstrating that these AuNPs trigger apoptosis by depolarizing the mitochondrial membrane and activating caspase-3, an element that is often overlooked in previous research. The significant cytotoxicity is confirmed by the IC₅₀ value of 27.5 µg/mL. Overall, this work contributes to the area of green nanomedicine by combining mechanistic confirmation of anticancer effectiveness with robust phytochemical-assisted production.