SUSTAINABLE GREEN SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES USING Coffea arabica HUSK WITH POTENTIAL BIOLOGICAL ACTIVITIES

Abstract

This research focused on the sustainable green synthesis of silver nanoparticles (AgNPs) using Coffea arabica husk, an agro-industrial byproduct, as a reducing and capping agent. The primary problem addressed by this study is the environmental challenges posed by agro-waste disposal and the limitations of conventional nanoparticle synthesis methods, which often involve toxic chemicals and high energy consumption. This eco-friendly approach provides an alternative to conventional chemical and physical methods, promoting waste valorization and reducing environmental impact. The objective of this research was to develop an efficient, sustainable method for synthesizing AgNPs while exploring their potential applications in antimicrobial and anticancer therapies. Bioactive compounds in the coffee husk extract were identified through liquid chromatography-mass spectrometry (LC-MS/MS), which facilitated the formation of AgNPs. The biosynthesized nanoparticles were characterized by UV-Vis spectrophotometry, showing an absorption peak around 400 nm, confirming successful AgNPs synthesis. Morphological analysis via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed spherical AgNPs with an average size of approximately 147 nm. Zeta potential measurements indicated good nanoparticle stability, while Fourier transform infrared spectroscopy (FTIR) confirmed the presence of functional groups responsible for nanoparticle stabilization. X-ray diffraction (XRD) analysis further verified the crystalline structure of the AgNPs, with diffraction peaks corresponding to the face-centered cubic structure of silver. The AgNPs demonstrated significant antibacterial activity in agar disc diffusion assays, effectively inhibiting bacterial strains such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis. Furthermore, Coffea arabica husk-derived AgNPs were tested for cytotoxicity using the MTS assay against the MCF-7 cancer cell line and L6 skeletal muscle cell line, showing selective cytotoxic effects on cancer cells with an IC50 value of 16.7 µg/mL, while exhibiting no toxic effects on normal skeletal muscle cells. These findings underscore the potential of Coffea arabica husk-derived AgNPs as promising antibacterial and anticancer agents, supporting their application in sustainable biomedical fields.