OXYSTELMA ESCULENTUM-MEDIATED AG/AGCL NANOPARTICLES AS POTENT ANTINEOPLASTIC AGENTS AGAINST MCF-7, HELA, AND HEPG2 CELLS: DLS-GUIDED SYNTHESIS, MULTI-TECHNIQUE CHARACTERIZATION, AND ANTIOXIDANT PROFILING

Abstract

Background: Plant-mediated (green) synthesis of silver nanoparticles (Ag-NPs) offers an eco-friendly alternative to physicochemical synthesis routes and is increasingly explored as a source of anticancer and antioxidant nanomedicine agents. Objectives: To establish the in vitro antineoplastic potential of Oxystelma esculentum-mediated Ag/AgCl nanoparticles against three human cancer cell lines, underpinned by DLS-guided formulation optimization, comprehensive physicochemical characterization, and antioxidant profiling. Methods: Five Ag-NP formulations (F1–F5) were synthesized at increasing plant-extract concentration and screened by DLS particle sizing; the optimum formulation was additionally characterized by zeta potential, UV Visible spectroscopy, powder X-ray diffraction (XRD; Scherrer and Williamson–Hall analysis), scanning electron microscopy (SEM) with automated particle-size-distribution analysis, energy-dispersive X-ray spectroscopy (EDX; four independent spectra), and Fourier-transform infrared (FTIR) spectroscopy. Antineoplastic activity was assessed by MTT assay against MCF-7, HeLa, and HepG2 cell lines in three independent biological replicates (n = 3), analysed by two-way ANOVA with Tukey's post hoc test, and antioxidant activity by the DPPH radical scavenging assay (n = 3), with one-way ANOVA applied to the DPPH dataset. Results: DLS screening showed particle size increasing monotonically with extract concentration (92–113 nm across F1–F5); the lowest-extract formulation (F1, 92 nm) was selected as optimum and carried forward for full characterization, with a zeta potential of −24.8 mV indicating moderate colloidal stability. UV-Vis analysis of the optimum formulation showed a surface plasmon resonance band at 430 nm. XRD confirmed a biphasic crystalline product comprising metallic Ag⁰ and AgCl, with Scherrer crystallite sizes of 27.6 ± 8.4 nm and 29.4 ± 3.9 nm, respectively. SEM revealed quasi-spherical particles (pooled mean diameter 74.3 ± 56.7 nm, n = 2,203; primary particle estimate 50.7 ± 37.7 nm at highest resolution), and EDX (mean of four spectra) confirmed Ag (10.90 ± 0.51 wt%) alongside Cl (5.38 ± 0.42 wt%; Ag:Cl atomic ratio 0.67 ± 0.02) and a C/N/O-rich organic capping layer, consistent with FTIR-identified O–H/N–H, C=C/amide, C–N/carboxylate, and Ag–O vibrations. Ag/AgCl NPs showed concentration-dependent cytotoxicity against MCF-7, HeLa, and HepG2 cells with mean IC50 values of 1.10 ± 0.04, 0.90 ± 0.03, and 0.90 ± 0.03 µg/mL (mean ± SD, n = 3), respectively, with significant concentration, cell-line, and interaction effects (two-way ANOVA, all p < 0.0001) — substantially more potent than several recently reported plant-mediated Ag-NP systems. DPPH scavenging increased significantly with concentration (one-way ANOVA, F(4,10) = 399.0, p < 0.0001), with an IC50 of 83.63 ± 1.37 µg/mL. Conclusion: Oxystelma esculentum-mediated Ag/AgCl nanoparticles, produced via a DLS-guided formulation optimization strategy, combine well-defined physicochemical properties and moderate colloidal stability with substantial anticancer potency and moderate antioxidant activity, supporting their candidacy for further pharmacological investigation as antineoplastic agents.