Abstract
Gold nanoparticles (AuNPs) were biogenically synthesized using the aqueous leaf extract of Pergularia daemia, with process optimization achieved via response surface methodology. The resulting nanoparticles were monodispersed, crystalline, and exhibited an average diameter of 110 ± 2.8 nm. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of flavonoids, terpenoids, and polyphenols as capping and stabilizing agents, contributing to the nanoparticles' colloidal stability for over six months. In vitro studies demonstrated significant dose and time-dependent antiproliferative effects of the biosynthesized AuNPs against human nasopharyngeal carcinoma (C666-1) cells, with the IC(50) decreasing from 26.8 μg/mL at 24 h to 16.44 μg/mL at 48 h. Microscopic examination revealed marked cytoplasmic damage, and mitochondrial dysfunction was confirmed via DAPI and AO/EtBr staining. RT-PCR analysis revealed a substantial upregulation of pro-apoptotic genes Bax, Caspase-3, and p53, alongside downregulation of the anti-apoptotic protein Bcl-2, confirming apoptosis induction via the intrinsic mitochondrial pathway. Importantly, the Pd-AuNPs exhibited selective cytotoxicity toward carcinoma cells over normal NP69 cells, highlighting their potential as a targeted therapeutic agent for nasopharyngeal carcinoma.