Copper oxide nanoparticles-mediated Heliotropium bacciferum leaf extract: Antifungal activity and molecular docking assays against strawberry pathogens

Abstract

In the current study, Heliotropium bacciferum leaf extract was used to biosynthesize copper oxide nanoparticles (CuO-NPs). Various analytical techniques were used to characterize the produced CuO-NPs. Transmission electron microscope investigation indicated well-distributed spherical particles in various development phases. The particles’ diameters ranged from 22.15 to 37.01 nm, with an average of 24.8 ± 6.1 nm. Energy dispersive X-ray examination confirmed the presence of nanoscale Cu ions at a high concentration, as seen by the strong signal peak at 1 keV. Fourier transform infrared spectrum revealed various functional groups on the green-produced CuO-NPs, as evidenced by multiple absorption beaks. The bands found at 3,195 and 2,916 cm−1 revealed that phenolic and flavonoid compounds’ alcohols and alkanes were stretching C–H. Also, a band at 1,034 cm−1 is typically attributed to CuO production. CuO-NPs exhibited significant bioactivity against isolated and molecularly identified fungal strains, including Rhizoctonia solani (OR116528), Fusarium oxysporum (OR116508), and Botrytis cinerea (OR116491). Remarkably, the highest inhibition percentages were recorded at 100 µg/mL, with values 81.48, 71.11, and 50.74% for R. solani, F. oxysporum, and B. cinerea, respectively. Molecular docking interactions revealed that the highest binding affinity of CuO-NPs was −5.1 for the oxidoreductase of B. cinerea and −5.2 and −5.4 for the chitin synthase of R. solani and F. oxysporum, respectively. Consequentially, the biosynthesized CuO-NPs could be employed as antifungal biocontrol agents, as well as using H. bacciferum leaf extract for the synthesis of nanoparticles for various sustainable agricultural applications.