Vol. 5, Issue 2, Part A (2023)

Background: Nanotechnology, concerned with the nanoparticles having a size of 1-100 nm in one dimension is one of the ultimate expeditiously advanced areas of technology that has opened up many new edges of research for modern day society. These nano-conjugates can be synthesized via different methods. Although, the green approach is the most favoured one as it is way more natural, less hazardous, and eco-friendly in nature. 
Method: Our present study gives an overview of two Citrus species plant (Family: Rutaceae) i.e., Citrus limon and Citrus aurantifolia leaf extract treated gold nano-conjugates synthesis. Subsequently after synthesis, gold nanoparticles were undergone through biophysical techniques; including Stability checking, UV-Vis Spectrophotometric analysis, DLS, and FT-IR followed by in vitro antibacterial and antioxidant profiling (HPLC-DAD screening of polyphenolics). 
Results: According to the results via different characterization methods, it is revealed that each of the nano-conjugate displayed a single sharp peak within the range of 500-550 nm. As well as particle size ranges within 7 nm-20 nm. Whereas FT-IR data of both crude leaf extract and their respective synthesized gold-nanoparticles establish the amalgamation of various bioactive compounds of the extracts with the gold nanoparticles. Presence of sinapic acid as a potent phenolic acid emphasizes the antioxidative nature of the plant itself. 
Conclusion: The in vitro antibacterial efficacy against two well-known bacteria and anti-oxidant activity using DPPH assay further enhances the stability of those green synthesized nano-conjugates.