ABSTRACT

Green Synthesis, a revolutionary approach in nanotechnology utilizes biological entities like plants, algae, microorganisms to synthesize nanoparticles which are eco-friendly, clean with cost effectiveness and efficiency in diverse application. This study aimed at synthesis, characterization of AgNPs by methanol, ethyacetate and aqueous extracts of lemon peel (Citrus lotifolia) and their application to health. C. Lotifolia was obtained from Nigerian Institute for Oil Palm Research (NIFOR). The pulverized C. Lotifolia was extracted using methanol, ethyacetate and aqueous solvents. AgNPs was synthesized by mixing 5mM AgNO₃ and 1 g of concentrated C. Lotifolia  extracts (1:1). The synthesized AgNPs was characterized using UV/Vis spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction Analysis (XRD), and Scanning Electron Microscope (SEM). The characterized AgNPs was subjected to antimicrobial and antioxidant test. The result of this study confirmed the synthesis by color change to brown. The result of the characterization of UV/Vis revealed Surface Plasmon Resonance (SPR) formed at 550 nm peak, the FTIR showed OH functional group stretch, XRD showed Bragg diffraction at 2θ⁰, 23.5, 25.5, 27, 28.5, 31.5, 36.5, 37.5, 45.5, 49.5, 52.5, corresponding to Miller indices (hkl) 001, 002, 020, 110, 141, 111, 112, 022,003, 023, 130, 220, while the SEM image revealed 10 to 100 nm particle size with agglomeration of the AgNPs. The result of the antimicrobial studies revealed bacteria inhibition <40% for AgNPs synthesized by methanol and aqueous extracts, while AgNPs synthesized by ethyacetate recorded bacteria inhibition >40%. AgNPs by methanol extracts of showed great potential as an antioxidant compared to standard (ascorbic acid) with 0.015 significant levels. The IC₅₀ value was lowest for AgNPs by methanol (1.09E¹²), ethy-acetate (55.2) and aqueous (58.2) extracts, compared to ascorbic acid (322.1). The result indicates that the antimicrobial and antioxidant activities of the nanoparticles was significant thus, the bioactive silver nanoparticles can be used in microbiological and pharmacological fields.