Synthesis of biogenic silver nanoparticles (bAgNPs) using leaf extract of Mirabilis jalapa and evaluation of anti-vibriocidal, anti-oxidant properties and cytotoxicity

Abstract

Abstract Acute hepatopancreatic necrosis disease and luminescent vibriosis are two major bacterial diseases of penaeid shrimp which are caused by gram negative pathogenic bacteria Vibrio parahaemolyticus (Vp) and Vibrio harveyi (Vh) respectively. These diseases cause massive mortality and huge economic loss worldwide in shrimp aquaculture. Extensive and inappropriate usage of antibiotics against these pathogens resulted in antibiotic resistant strains. Drug repurposing appears to be an appropriate solution to eliminate the antibiotic resistance in pathogens. In the present study, biogenic silver nanoparticles (bAgNPs) are synthesized by reducing AgNO3 using aqueous extract of Mirabilis jalapa (MJ) leaves. The anti-oxidant, cytotoxic and anti-vibriocidal activity of bAgNPs against Vp and Vh are evaluated. The formation of silver nanoparticles was confirmed by the appearance of dark brown colored solution and with a maximum absorption peak at 434nm. The characterization of bAgNPs using FESEM, TEM, XRD, FTIR, and DLS has confirmed that the nanoparticles are crystalline, spherical in shape with an approximate diameter of 50nm, and have capping agents. The diameter of microbial growth inhibition zones for Vp and Vh are 26mm and 23mm respectively. Further, the MIC values for Vp and Vh are 31.25µg/mL and 93.75µg/mL respectively. The DPPH and FRAP assays showed substantial anti-oxidant activity with IC50 values of 67.39µg/mL and 5.509µg/mL respectively. MTT assay to check cytotoxicity effect of bAgNPs on Vero cells resulted very less toxicity at maximum concentration tested with an IC50 value of 293.5µg/mL. Therefore, the biogenic silver nanoparticles synthesized from leaves of MJ showed effective anti-vibriocidal and anti-oxidant properties with negligible cytotoxic effect.