Vitis heyneana extract mediated synthesis of silver nanoparticles with high bioactive and colorimetric sensing properties

The green synthesis of inorganic nanoparticles using plant extracts has been an important strategy to mitigate the uses of hazardous chemicals and thus reduce toxic by-products. We herein report for the first time the synthesis of silver nanoparticles (AgNPs) utilizing Vitis heyneana fruit peel as a key agent. Specifically, oleanolic acid was found in the extract and its crucial role as both reducing and stabilizing agent was experimentally evidenced. The as-synthesized AgNPs were morphologically and structurally characterized to possess quasi-spherical shapes with an average diameter of 11 nm and exhibit polycrystalline nature. Bioactive studies indicated that as-synthesized AgNPs revealed potent antimicrobial activities against Lactobaccillus plantarum, Pseudomonas aeruginosa, and Aspergillus flavus, demonstrating an IC₅₀ value of 20.00 ± 2.05 μg ml⁻¹ and a MIC value of 32 ± 0.03 μg ml⁻¹ (against Pseudomonas aeruginosa); the NPs also possessed superior antioxidant activities with an IC₅₀ value of 23.22 ± 1.25 μg ml⁻¹ compared to vitamin C (18.23 ± 0.15 μg ml⁻¹). The AgNPs further revealed capabilities of colorimetrically detecting Hg²⁺ ions with a limit of detection of 0.048 μM and a limit of quantitation of 0.16 μM. These findings therefore suggest promising uses of the phytosynthesized AgNPs in nanomedicine and sensing technology.