Antibacterial and cytotoxic activity of biosynthesis gold nanoparticles using Morus nigra leaf extract

In this study, the synthesis of Au nanoparticles (AuNPs) was carried out using a green approach using Morus nigra (M. nigra) leaf extract. The obtained AuNPs were verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and UV-Vis spectroscopy. The synthesis of AuNPs was first confirmed by a characteristic surface plasmon resonance peak at approximately 553 nm in the UV-Vis spectrum. While the crystalline structures of AuNPs with face-centered cubic structure were confirmed by XRD analysis, the average diameter of the nanoparticles was determined to be 18 ± 6 nm by TEM images. FT-IR analysis revealed that biomolecules such as proteins, flavonoids, terpenoids and polyphenols found in M. nigra extract play important roles in both the reduction and stabilization of nanoparticles. The antibacterial and antibiofilm properties of the synthesized AuNPs were evaluated using the microdilution method, biofilm inhibition test, and cell viability tests. AuNPs showed antibacterial activity against both gram-positive and gram-negative bacteria. In addition, cytotoxicity assessments showed that AuNPs had a dose-dependent inhibitory effect on PC3 prostate cancer cells, while negligible toxicity was observed against HEK-293T normal human embryonic kidney cells.