Cytotoxicity Study of Gold Nanoparticle Synthesis Using Aloe vera, Honey, and Gymnema sylvestre Leaf Extract

[Image: see text] Gold nanoparticles (AuNPs) have gained importance in the field of biomedical research and diagnostics due to their unique physicochemical properties. This study aimed to synthesize AuNPs using Aloe vera extract, honey, and Gymnema sylvestre leaf extract. Physicochemical parameters for the optimal synthesis of AuNPs were determined using 0.5, 1, 2, and 3 mM of gold salt at varying temperatures from 20 to 50 °C. X-ray diffraction was used to evaluate the crystal structure of AuNPs, which came out to be a face-centered cubic structure. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis confirmed the size and shape of AuNPs between 20 and 50 nm from the Aloe vera, honey, and Gymnema sylvestre, as well as large-sized nanocubes in the case of honey, with 21–34 wt % of gold content. Furthermore, Fourier transform infrared spectroscopy confirmed the presence of a broadband of amine (N–H) and alcohol groups (O–H) on the surface of the synthesized AuNPs that prevents them from agglomeration and provides stability. Broad and weak bands of aliphatic ether (C–O), alkane (C–H), and other functional groups were also found on these AuNPs. DPPH antioxidant activity assay showed a high free radical scavenging potential. The most suited source was selected for further conjugation with three anticancer drugs including 4-hydroxy Tamoxifen, HIF1 alpha inhibitor, and the soluble Guanylyl Cyclase Inhibitor 1 H-[1,2,4] oxadiazolo [4,3-alpha]quinoxalin-1-one (ODQ). Evidence of the pegylated drug conjugation with AuNPs was reinforced by ultraviolet/visible spectroscopy. These drug-conjugated nanoparticles were further checked on MCF7 and MDA-MB-231 cells for their cytotoxicity. These AuNP-conjugated drugs can be a good candidate for breast cancer treatment that will lead toward safe, economical, biocompatible, and targeted drug delivery systems.