EVALUATION OF SOLVENT POLARITY ON THE NANOPARTICLEFORMING POTENTIAL OF SOLANUM VIRGINIANUM LEAF EXTRACTS

Abstract

The green synthesis of silver nanoparticles via plant-mediated reduction depends fundamentally on the presence of functional biomolecules capable of electron donation and surface stabilization. In the present study, dried Solanum virginianum leaves were extracted separately by 72 h maceration in n-hexane and methanol, yielding 1.60% and 13.60% crude extract, respectively representing an approximately 8.5-fold higher extractive yield for methanol. Qualitative phytochemical screening and FTIR spectroscopy were employed to map functional group profiles and evaluate their capacity to drive Ag⁺ bio reduction under solar irradiation. Following aqueous reconstitution, the methanolic extract (CMM) demonstrated distinct bio reduction potential upon reaction with 1 mM AgNO₃, yielding a prominent chromatic transition to dark reddish-brown consistent with characteristic of colloidal metallic silver (Ag⁰). In contrast, the hexane extract (CMH) exhibited no discernible color change, remaining inactive. Spectral profiling revealed that CMM was enriched with broad hydrogen-bonded O–H stretching (3326.21 cm⁻¹) and intense C– O/C–N stretching vibrations (1016.95 cm⁻¹), representing active electron-donating moieties. Conversely, CMH was dominated by lipophilic aliphatic chains (2856.84–2934.03 cm⁻¹) and an ester carbonyl band (1734.55 cm⁻¹) lacking accessible reduction centers. These findings establish a direct mechanistic link between solvent polarity, secondary metabolite extraction, and the feasibility of plant-assisted silver reduction, identifying methanol as an appropriate solvent system for future nano formulation studies involving S. virginianum leaves.