Caucasian and Egyptian chitosan/propolis nanocomposites inhibit deformed wing virus in Apis mellifera L. cell lines.

Honey bees face threats from a variety of pathogens and viruses, the most dangerous of which is the deformed wing virus [DWV]. Using natural materials as treatments or nutritional supplements for bees is the ideal solution, especially when transformed into nanoparticles. Propolis is a resinous product collected from honeybee colonies and is known for its wide-ranging therapeutic properties. The nanocomposite of the chitosan/ propolis alcoholic extracts were prepared and characterized for determining their chemical and physical properties. Cytotoxicity assay and antiviral activity of the prepared composites were also determined using cell culture from the head of adult honey bees in a dose-response assay. A quantitative real time-polymerase chain reaction [RT-qPCR] was done to measure their effects on the deformed wing virus load. The characterization results showed that the Caucasian propolis-chitosan nanocomposite have a higher phenols and flavonoid content and surface area compared to the Egyptian propolis. The Caucasian propolis showed higher toxicity to the cultured cells than the Egyptian propolis. The Chitosan-Caucasian propolis nanocomposites caused a more reduction in the deformed wing viral load of the honey bee cell line than the Egyptian one compared to the raw propolis. It is recommended to use the chitosan-Caucasian propolis nanocomposite as therapeutic and nutritional supplements for decreasing the deformed wing viral load in the honey bees a process that may help in increasing their performance and bee-product production.