Selective cytotoxicity properties of <i>Kalanchoe daigremontiana</i> -mediated gold nanoparticles against Jurkat leukemia cells

In this study, gold nanoparticles were synthesized using an extract of<i>Kalanchoe daigremontiana</i>(<i>K. daigremontiana</i>) and biologically evaluated against the crude extract. The effects of both treatments were assessed in Jurkat T-cell leukemia cells, as a cancer model, and in 3T3-L1 fibroblasts, as a non-malignant control. Nanoparticle characterization revealed polyhedral AuNPs with an average diameter of 125.49 nm and an organic surface coating derived from the plant extract. Biological activity was evaluated using cell viability (MTT assay), intracellular reactive oxygen species (ROS) quantification, and plasma membrane permeability assays. The<i>K. daigremontiana</i>-derived AuNPs exhibited selective, concentration-dependent cytotoxicity toward Jurkat cells through a multifactorial mechanism involving enhanced cellular uptake, oxidative stress induction, and membrane integrity disruption, while sparing non-malignant fibroblasts. In contrast, the crude extract induced a plateau-like cytotoxic response in 3T3-L1 fibroblasts (maximum cell death of 37.72%) and only mild cytotoxicity in Jurkat cells (18.23% at 150 μg ml^-1), consistent with predominantly ROS-independent activity. This comparative analysis demonstrates that green synthesis of AuNPs fundamentally alters the biological mechanism of<i>K. daigremontiana</i>, highlighting the added therapeutic potential of plant-derived AuNPs for leukemia treatment.