Synthesis of silver nanoparticles using Nymphaea nouchali-derived 9-Octadecenal: Antimicrobial, antidiabetic properties and in Silico ADMET insight

Abstract

Nanotechnology leverages the extremely small size of materials within the range of 1–100 nm (nanoparticles), particularly silver nanoparticles, and their significant surface-to-volume ratio for therapeutic applications. Following the principle of green and sustainable chemistry, 9-octadecenal compound was isolated from Nymphaea nouchali , an aquatic weed and pollutant, first-ever as a reductant to synthesise AgNPs for biomedical use. Qualitative phytochemical screening and successive extraction were performed on the plant using a cold extraction method on a polarity scale. The 9-octadecenal compound was analysed with GC–MS and 1 H NMR. The reduction process was monitored with a UV–visible spectrophotometer. Molecular vibrations of O H, C H, C O, and C O at different intensities were observed in FTIR analysis, and XRD validated a face-centred cubic Ag structure. SEM-EDAX and XRF techniques further confirmed the AgNPs. The antimicrobial assay was done on Klebsiella sp. , Salmonella sp. , Streptococcus pneumoniae and Candida albicans . Staphylococcus aureus (ATCC 25923) and Escherichia coli (25922) were also used. An in vitro assay targeting α-amylase activity was used to evaluate the antidiabetic properties, and ADMET profiling was conducted to assess toxicity and cytotoxicity. AgNPs absorbed around 450 nm absorption wavelength. The AgNPs exhibited strong growth inhibition against all test organisms and also inhibited α-amylase, although not as effectively as the control. The ADMET predicted the isolated compound as non-toxic (LD 50 of 5000 mg/kg) and with cytotoxic potential. Thus, the AgNPs are a latent candidate for an antibacterial drug.