Biosynthesis of silver nanoparticles using leaves of Mentha pulegium, their characterization, and antifungal properties

Currently, the prime focus in agricultural research is on sustainability and protection of agricultural produce with minimal use of synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were synthesized using fresh leaves of Mentha pulegium (M.p) through a simple, easy, and economical method. The formation of M.p-AgNPs was ascertained with UV-visible spectroscopy that gave a surface plasmon resonance peak at 430 nm. Further, M.p-AgNPs were characterized by energy dispersive X-Ray analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering, and Fourier-transform infrared (FTIR) spectroscopy. The DLS spectrum and TEM microphotographs showed that the M.p-AgNPs were small in size, measuring between 4 and 60 nm. Significant hyphal growth inhibition of some selected fungal phytopathogens was achieved after exposing them to various concentrations of M.p-AgNPs. The M.p-AgNPs (40 mu g-mL(-1)) suppressed the fungal mycelial growth of all the test isolates significantly. When compared to the control, Fusarium solani (63% inhibition) and Alternaria alternata (61% inhibition) showed the highest inhibition. Likewise, spore germination was inhibited in a potent manner. Hence, based on the findings of the present study, M.p-AgNPs can be used to create a low cost, nontoxic, eco-friendly fungicide to control the growth and proliferation of some fungal phytopathogens in the agricultural sector.