Antioxidant and Antimicrobial Synergistic Properties of Silver Nanoparticles Synthesized with Leaf extract of Pennisetum purpureum

The rising demand for silver nanoparticles obtained by green method has made it necessary to search for readily available bio-materials that can serve as sustainable bio-reductant and stabilizers. Pennisetum purpureum is a readily available tropical plant commonly used as food, feed for livestock, and thermal energy production. In this study, extract from the leaves of Pennisetum purpureumwas explored to prepare silver nanoparticles (Perp-AgNPs). The structural and optical properties of the particles were studied with scanning electron microscope, Ultraviolet-Visible spectrophotometer, Fourier transform infrared (FTIR) spectrometer and X-ray diffractometer. The antioxidant property of the Perp-AgNPs was studied by investigating its ability to scavenge 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical. Enhanced activity of 83% was obtained by 1 mg/mL of the Perp-AgNPs after 10 min of scavenging. In addition, IC50 = 0.179 mg/mL was observed by the Perp-AgNPs. The antimicrobial property of the Perp-AgNPs was investigated against broad range of microorganisms, namely, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus mutans, Bacillus subtilis, Methicillin resistant Staphylococcus aureus, Salmonella typhi and Candida albicans. The minimum inhibitory concentration values ranged from 0.313 to 1.25 mg/mL with Psuedomonas aeruginosa, Candida albicans and Methicillin resistant staphylococcus aureus being the most susceptible. The Perp-AgNPs also demonstrated the ability to enhance the efficacy of standard antibiotic and anti-fungal agents. The antimicrobial combinatory effects were synergy and partial synergy against the selected microorganisms. The results from the study show that silver nanoparticles prepared with leaves extract of Pennisetum purpureum have adequate antioxidant and antimicrobial properties for applications in nanomedicine.