Synthesis of Biogenic Silver Nanoparticles (bAgNPs) Using Leaf Extract of Mirabilis jalapa and Evaluation of Anti-vibriocidal, Anti-oxidant properties and Cytotoxicity

Abstract

Acute hepatopancreatic necrosis disease (AHPND) 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 antibiotic resistance in pathogens. In the present study, biogenic silver nanoparticles (bAgNPs) are synthesized by reducing AgNO3 using the 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 bAgNPs was confirmed by the appearance of a dark brown coloured solution and with a maximum absorption peak at 434 nm. The characterization of bAgNPs using FESEM and EDX, TEM, XRD, FTIR, and DLS has confirmed that the nanoparticles are crystalline and spherical in shape with an approximate diameter of 50 nm and have capping agents. The diameters of microbial growth inhibition zones for Vp and Vh are 26 mm and 23 mm respectively. Further, the MIC values for Vp and Vh are 31.25 µg/mL and 93.75 µg/mL respectively. The DPPH and FRAP assays showed substantial anti-oxidant activity with IC50 values of 67.39 µg/mL and 5.509 µg/mL respectively. MTT assay to check the cytotoxicity effect of bAgNPs on Vero cells resulted in very less toxicity at the maximum concentration tested with an IC50 value of 293.5 µg/mL. Therefore, the bAgNPs synthesized from leaves of MJ showed effective anti-vibriocidal and anti-oxidant properties with negligible cytotoxic effects.