Green Synthesis of Copper Nanoparticles Using Polyalthia longifolia Roots and their Bioactivities Against Escherichia coli, Staphylococcus aureus, and Candida albicans

Abstract

The synthesis of copper nanoparticles (CuNPs) has been the center of researchers’ attention due to their potential in various fields, particularly in medicine and pharmacy. The objective of this research was to synthesize CuNPs by using the extract from Polyalthia longifolia roots via an organic solvent-free approach. The roots of P. longifolia were extracted using boiling water and subsequently used to synthesize CuNPs from CuSO4 solution. The resultant nanoparticles were then characterized using UV–Vis spectrophotometer, Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope–energy dispersive X-ray (SEM-EDX), and transmission electron microscopy (TEM). Kirby–Bauer sensitivity test was performed against Staphylococcus aureus, Escherichia coli, and Candida albicans. In the results, we found that the total phenolic content and total flavonoid content of the extract were 85.43 GAE/g dry extract and 0.78 QE/g dry extract, respectively. The characterizations revealed that the obtained nanoparticles possess a spherical shape and diameters of around 2 to 10 nm. The XRD suggests that the nanoparticles were occupied by copper (0) and copper oxides (CuO, CuO2, and Cu2O). The synthesized CuNPs yielded inhibition zones of 17.2 ± 0.2, 15.6 ± 0.2, and 13.7 ± 0.1 mm against S. aureus, E. coli, and C. albicans, respectively. In conclusion, aqueous extract from the roots of P. longifolia can be used to synthesize CuNPs that could be used as an antibacterial and antifungal agent.

Keywords

• antimicrobial activity
• aqueous extract
• copper nanoparticles
• polyalthia longifolia