Phytosynthesized bimetallic gold-copper nanoparticles using Anacardium occidentale leaf extract and its potential antidiabetic activity

This study describes the anti-diabetic property of gold-copper nanoparticles (Au-CuNPs) synthesized using Anacardium occidentale leaf extract. The synthesized Au-NPs was characterized with UV–UV-Visible spectroscopic technique, Fourier-transform infrared spectroscopy, Transmission electron microscopy, X-ray diffraction, and Energy-dispersive X-ray spectroscopy. The formation of the Au-NPs was confirmed by the two distinct peaks on the UV–UV-Visible spectrum at 278 and 532 nm, which correspond to the absorbance of Cu and AuNPs, respectively. The FTIR analysis revealed the involvement of biomolecules with –OH, –NH, –C O, and aromatic –C C- among other functional groups in the Anacardium occidentale leaf extract as the reducing and capping agents. Transmission electron microscopy and X-ray diffraction analysis confirmed the synthesized Au-CuNPs as spherical and crystalline, with particle size in the range of 2–37 nm. The biosynthesized Au-CuNPs displayed effective inhibition against α-amylase and α-glucosidase. At 100 μg/mL, the percentage inhibition of Anacardium occidentale leaf extract, biosynthesized Au-CuNPs, and acarbose was 21, 66, and 80 % against α -amylase and 37, 75, and 83 % against α -glucosidase. The IC 50 values of Anacardium occidentale leaf extract, biosynthesized Au-CuNPs, and Acarbose were 149, 50, and 35, against the α-glucosidase and 128.74, 46.16, and 28.40 against α-amylase, respectively. The order of inhibition against α-glucosidase and α-amylase was acarbose > biosynthesized Au-CuNPs > Anacardium occidentale leaf extract. The results show that the biosynthesized Au-CuNPs exhibited a significant level of inhibition against α -glucosidase and α-amylase. This result revealed that Au-CuNPs biosynthesized from Anacardium occidentale leaf extract could be a potential candidate to combat diabetes. • Au-CuNPs were biosynthesized using Anacardium occidentale leaf extract, showing enhanced anti-diabetic properties. • SPR, FTIR, TEM, and XRD confirmed the formation, biomolecule role, shape, and structure of the synthesized Au-CuNPs. • The Au-CuNPs showed strong α-amylase and α-glucosidase inhibition, outperforming acarbose and monometallic NPs.