Plant-Based Gold Nanoparticles for Targeted Drug Delivery in Breast Cancer: Progress and Prospects in Pakistan

Background: Breast cancer remains a major cause of morbidity and mortality among women, particularly in low- and middle-income countries where delayed diagnosis, limited access to targeted therapies, and treatment-related toxicity continue to compromise outcomes. Plant-mediated gold nanoparticles have emerged as a promising area of green nanomedicine because they combine the physicochemical advantages of gold nanoparticles with the reducing, stabilizing, and bioactive properties of plant-derived phytochemicals. Objective: This narrative review aimed to critically synthesize the progress, methodological limitations, and translational prospects of plant-based gold nanoparticles for targeted drug delivery in breast cancer, with emphasis on evidence relevant to Pakistan. Methods: A structured narrative synthesis was conducted using literature related to gold nanoparticles, green synthesis, medicinal plant extracts, breast cancer models, targeted drug delivery, cytotoxicity, apoptosis, biocompatibility, and nanomedicine translation. Evidence was organized thematically according to synthesis methods, plant sources, nanoparticle characterization, anticancer mechanisms, drug-delivery potential, biosafety, methodological challenges, and translational readiness. Because of heterogeneity in plant extracts, nanoparticle preparation, experimental models, assays, and outcome reporting, pooled quantitative analysis was not performed. Results: The strongest evidence was concentrated in laboratory-scale green synthesis, physicochemical characterization, and in vitro cytotoxicity against breast cancer cell lines such as MCF-7 and MDA-MB-231. Plant-mediated gold nanoparticles were associated with enhanced cellular uptake, reactive oxygen species generation, mitochondrial dysfunction, apoptosis-related signaling, DNA fragmentation, and preliminary drug-delivery potential, including doxorubicin conjugation and sustained release. However, evidence for in vivo efficacy, pharmacokinetics, biodistribution, long-term toxicity, regulatory readiness, and clinical application remained limited. Conclusion: Plant-based gold nanoparticles represent a promising but preclinical platform for targeted breast cancer drug delivery. Their future translational value in Pakistan depends on standardized synthesis, reproducible characterization, mechanistic validation, long-term biosafety assessment, and rigorous preclinical-to-clinical development.