Diseño de sistemas de encapsulación de productos bioactivos para mejorar sus propiedades físico-químicas y su aplicación en sistemas agronómicos o farmacológicos

Resumen

Physicochemical properties of relevant natural products, and derivatives, limit their potential application in agriculture and pharmacology. These properties, such as water solubility, soil stability and bioavailability need to be improved in order to enhance their practical use as an agrochemical or drug. Recent years, encapsulation has arisen as an efficient route to modulate the attributes of organic molecules, from solubility and stability to bioavailability. This PhD dissertation is focused in organic structures or structures composed by trace elements which could be innocuous or nonactive when applied to higher plants or human cell lines, and they could host bioactive compounds inspired by nature. During this work, polymeric nanoparticles have been synthesized, whose inner hollow is composed by several cavities where bioactive compounds against parasitic plants are hosted. Supramolecular polymer micelles were synthesized by employing cyclodextrins and phosphatidylcholine to host provitamin A, promoting controlled release of the guest with anti-tumor effect in skin cell lines. On the other hand, dimeric disulphides with potent phytotoxic effect against weeds that infect main Mediterranean crops have been encapsulated in nanotubes and metalorganic frameworks. In case of nanotubes, they were generated by self-assembly effect of lithocholic acid in neutral media. Metal-organic frameworks are constituted by zinc as metal core, and imidazole derivatives as organic linker; the pores of the structure are filled with disulphides, and the surface is functionalized with sugar derivatives to enhance the solubility and transport properties. The improvements of the physico-chemical properties and bioactivity observed on all the nanostructures synthesized, along with short and simple preparation methods, prove the great potential of these products for the practical application of new agrochemicals and drugs based on natural products.