Formulation and characterization of the biological activities of green synthesized zinc oxide nanoparticles from Annona muricata leaf extract

Annona muricata belongs to the family Annonaceae and the leaf extract has traditionally been used as an antipyretic, anti-diabetic, antihypertensive, and antimalarial. The study aims to formulate zinc oxide nanoparticles (ZnO NPs) using Annona muricata leaf extract (AME) and evaluate its biological activities. The biosynthesized ZnO NPs were characterized using UV-vis spectroscopy, FTIR, XRD and SEM. GC-MS analysis of AME indicated sesquiterpenes, acetogenins, alkaloids, flavonoids, fatty acids and other compounds. The presence of ZnO NPs was confirmed by the UV-vis absorption spectrum with a peak at 370 nm. XRD and FTIR showed the stabilized ZnO NPs using AME bioactive compounds with an average particle size of 79.14 nm. SEM and EDX revealed spherical and hexagonal morphology. Minimum inhibitory concentration experiments revealed that MIC values for P. aeruginosa and B. subtilis were 1.25mg/mL and 0.32mg/mL, respectively. Antioxidant activities of the AME, AME-ZnO NPs and ascorbic acid (standard) using DPPH assay revealed IC50 values of 2.17mg/mL, 1.66mg/mL and 0.23mg/mL, respectively. The formulated ZnO NPs also aided in the photocatalysis of methylene blue at a degradation rate of 66.8% after 180 min. These results collectively highlight the promising therapeutic potential of A. muricata biogenic zinc oxide nanoparticles for developing future therapies due to antibacterial, photocatalytic and antioxidant activities.