Comparative In Vitro Assessment of Antimicrobial, Anticancer, and Antioxidant Activities of Persea americana and Diospyros kaki Leaf Extracts versus their Green-Synthesized Silver Nanoparticles

Persea americana (Avocado) and Diospyros kaki (Persimmon) trees possess nutritional and therapeutic values. The various preparations from different parts of the plant, especially the leaves, have been utilized in folk medicine to manage multiple health conditions. This study involved the green production of silver nanoparticles (Ag-NPs) utilizing avocado and persimmon leaf aqueous extracts. The Ag-NPs were well-characterized using UV-Vis spectroscopy, TEM, FTIR, zeta potential, and particle size. The synthesized Ag-NPs from avocado extract exhibited spherical morphology with particle sizes ranging from 5.21 to 14.6 nm, while those produced from persimmon extract were also spherical, with sizes varying between 6.78 and 15.6 nm. The green-synthesized Ag-NPs demonstrated enhanced antioxidative, antibacterial, and anticancer capabilities compared to crude ethanolic extracts of avocado and persimmon. The total phenolic content (TPC) and total flavonoid content (TFC) analyses showed that avocado leaves exhibited the highest values, recording 425.28 ± 5.48 mg GAE/g and 245.63 ± 3.11 mg GAE/g, respectively. In contrast, persimmon leaves presented the lowest TPC and TFC, with 382.34 ± 6.56 mg GAE/g and 100.74 ± 2.05 mg GAE/g, respectively. Besides, the Ag-NPs synthesized from Persea americana and Diospyros kaki plants exhibited enhanced antioxidant activity at a 1000 μg/mL concentration with increases of 84.6±0.12% and 87.6±0.12%, from DPPH, 80.4±0.05% and 81.9±0.12% from ABTS, and 90.8±0.11% and 95.7±0.09% as determined by the FRAP test, respectively. The Ag-NPs from both plants exhibited remarkable antibacterial and antifungal activities. The prepared Ag-NPs from avocado aqueous leaf extract showed a significant cytotoxic effect against the Caco2 cell line, inhibiting the cell viability by 97.51% at a concentration of 320 μg/mL. Due to the elevated concentration of bioactive compounds in avocado, it can be used as a bioresource in medical uses. Ag-NPs synthesized from avocado and persimmon leaf extracts can also be effectively utilized as promising antioxidants, antimicrobials, and anticancer agents.