Optimization for synthesis of silver nanoparticles through response surface methodology using leaf extract of Boswellia sacra and its application in antimicrobial activity.

In the present work, leaf extract of Boswellia sacra was used as reductant for synthesis of silver nanoparticles (AgNPs). The variables such as volume of Boswellia sacra leaf extract (1%), volume of silver nitrate (1 mM), and temperature were optimized by response surface methodology via Box-Behnken design for the synthesis of AgNPs. Design-Expert software generated the optimum conditions for the highest yield of silver nanoparticles as 8 mL of 1 mM AgNO3, 8 mL of 1% Boswellia sacra leaf extract, and temperature = 55 °C. The formed AgNPs were isolated and purified by centrifugation process using ethanol/ distilled water. AgNPs were characterized using FTIR, SEM, TEM, EDX, and XRD. AgNPs showed surface plasmon resonance absorption band at 422 nm. XRD pattern indicated the crystalline nature of the particles (diameter 11.17 to 37.50 nm) with face-centered cubic structure. SEM and TEM images highlighted the formation of spherical AgNPs. The energy dispersive spectroscopic spectrum confirmed the presence of elemental silver. The microbial activity of AgNPs was evaluated against bacteria and fungi. Synthesized AgNPs were very effective against Gram-positive E. coli bacterial strains and fungal strains (Penicillium chrysogenum).