Antioxidant Potential of the Biosynthesized Silver, Gold and Silver-Gold Alloy Nanoparticles using Opuntia ficus-indica extract

Nanobiotechnology has become a resourceful/crucial research area due to their copious applications in industrial, pharmacological and medical fields. In the current study, silver nanoparticles (OFI-AgNPs), gold nanoparticles (OFI -AuNPs) and bimetallic alloy nanoparticles (OFI-Ag-AuNPs) were mediated with Opuntia ficus indica (OFI) extract. Evaluation of antioxidant potential of the biosynthesized nanoparticles was done through total phenolic content (TPC), total flavonoid content (TFC) and Nitric oxide scavenging assay. The nitric oxide scavenging activity, total phenolic and total flavonoid contents of the synthesized nanoparticles increased in a dose dependent manner as compared to the standard. The OFI-AuNPs had highest total phenol of 258.28 µg GAE/g and OFI-extract gave the least value of 216.64 µg GAE/g at concentration of 100 µg/ml. The highest value of total flavonoid content (83.88 µg g-1 QE) was recorded at OFI-AgNPs, while the least value of 21.38 µg g-1 QE obtained in OFI-extract. OFI-Ag-AuNPs showed the highest nitric scavenging power of 50.8%, followed by OFI-AgNPs (42.2%), OFI-AuNPs (40.3%) and the least value of 29.7% were obtained in OFI-extract at concentration of 100 µg/mL. These results indicate Opuntia ficus indica as a suitable biomaterial for the synthesis of the nanoparticles which can be utilized as an antioxidant agent. In conclusion, these fascinating bioactivities exhibited by the synthesized nanoparticles established their usefulness in the production of antioxidants OFI-AgNPs, OFI-AuNPs and OFI-Ag-AuNPs for their biomedical applications Keywords: Opuntia ficus indica, antioxidant activity, nanoparticles, nitric oxide, total phenolic (TPC), flavonoid content (TFC)