Synthesis of rotenone loaded zein nano-formulation for plant protection against pathogenic microbes

Rotenone (RN) is a naturally occurring isoflavone found in the root or rhizomes of fabaceae (a plant family), known for its insecticidal/pesticidal properties. Rotenone was loaded in zein nanoparticles (ZSC) by antisolvent precipitation method at room temperature. The synthesized nanoparticles showed self-assembled spherical nanostructures having 425.67 ± 7.02 and 471.33 ± 10.60 nm of hydrodynamic radii with -14.23 ± 0.21 and -17.64 ± 0.89 mV zeta potential for ZSC and RNZSC (rotenone loaded zein nanoparticles), respectively. The encapsulation of rotenone was confirmed by FTIR, ¹H NMR and DSC studies. A significant encapsulation efficiency of 95.82 ± 0.038% and 5.99 ± 0.002% loading efficiency were determined by HPLC studies. Synthesized RNZSC showed excellent antimicrobial activity against plant pathogens- P. syringae and F. oxysporum. Our studies showed for the first time direct evidence of antimicrobial activity of rotenone against plant pathogens. A similar approach could be adopted for developing several new botanical based nano-formulations with their known insecticidal effect, to control certain plant diseases in an environment friendly and sustainable manner.