Antibacterial, antioxidant and catalytic activities of green synthesized Copper Nanoparticles using Limonia acidissima fruit pulp extract

In this study, Copper Nanoparticles (CuNPs) were synthesized by a green method using the aqueous extract of Limonia acidissima (LA) fruit pulp by microwave irradiation technique. The UV-Vis data revealed the formation of Cu Nanoparticles and Surface Plasmon resonance (SPR) band appear at 567 nm. For the microwave assisted green synthesis of CuNPs, the optimum conditions were determined as 180 sec microwave time, 0.5% concentrations of LA fruit pulp aqueous extract, 10 mM concentration of Cu(NO 3 ) 2 and pH-7 of the solution. FTIR confirmed that Flavonoids and alkaloids present in LA fruit pulp were utilized in the formation of Cu Nanoparticles and capping the CuNPs surface. XRD analysis showed that the CuNPs had a face-cenered cubic (FCC) crystal structure. The TEM analysis confirmed the spherical shape with an average size around 12 nm. EDX confirmed the presence of elemental Copper. The LA capped CuNPs were found to have catalytic properties in the presence of NaBH 4 due to their ability to reduce rhodamine B (RhB) within 6 min of reaction time. The reaction kinetics followed pseudo-first-order with rate constant 0.393 min −1 . The green synthesized CuNPs demonstrated notable anti-oxidant activity(66.2% with 60 µg/mL concentration of CuNPs in the DPPH assay) and they have shown good anti-bacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus at concentration 20 µg/mL, with a zone of inhibition as 2 mm, 2.2 mm, 2.5 mm, 3.8 mm respectively. The present study proves that CuNPs are effective, economical and multifunctional and they can be used in a variety of therapeutic and catalytic applications.