Comparison of catalytic activity and antimicrobial properties of palladium nanoparticles obtained by Aloe barbadensis and Glycine max extracts, and chemical synthesis

Palladium nanoparticles (PdNPs) were synthesized from potassium tetrachloropalladate (K 2 PdCl 4 ) with chemical synthesis using NaBH 4 , and with Aloe barbadensis and Glycine max aqueous extracts as a reducing agent. The synthesized PdNPs were quasi-spherical with 34.24 ± 5.14 nm for A. barbadensis , 19.90 ± 2.84 nm for G. max, and 11.74 ± 1.58 nm for chemically produced PdNPs. Hydrodynamic size and zeta potential were 3174.33 ± 640.9 nm and -18.5 ± 2.11 mV for A. barbadensis ; 104.4 ± 0.44 nm and -29.47 ± 0.65 mV for G. max ; and 1572.33 ± 110.17 nm and -21.17 ± 1.72 mV for chemically synthesized PdNPs. G. max PdNPs showed better stability than A. barbadensis PdNPs . Spectroscopy analysis suggests that hydroxyl and phenolic compounds participate in a redox reaction with tetrachloropalladate ion. High-Pressure Ion Chromatography (HPIC) confirms the participation of reducing sugars in a redox reaction. 1 ’-1’ diphenyl picryl-hydrazyle (DPPH) scavenging of G. max was 40.61 ± 2.73%, A. barbadensis of 26.21 ± 4.61%, and chemical PdNPs of 29.85 ± 6%. All PdNPs catalyzed the reaction of NaBH 4 with methylene blue, methyl orange, and 4-nitrophenol, except Coomasie Blue. All microbial strains except C. albicans exhibited 0% of growth with the highest concentration. G. max and A. barbadensis PdNPs exhibit similar antioxidant, catalytic and antimicrobial properties than chemical PdNPs.