Cyclodextrin nanosponges as bioenhancers of phytochemicals

Bioavailability is the biggest obstacle to the effectiveness of biologically active compounds. Based on a set of physicochemical requirements we can determine if the compound fulfills the drug-like character and if it has the potential to become an active pharmaceutical ingredient (API) with confirmed and thoroughly examined activities. This practice is widely used in drug design of entirely new APIs, but also in search of pharmacological active substances in large compound bases such as plant-derived substances. The chemical structure diversity of plant-based compounds assures that some of them have to be well bioavailable due to good lipid membrane permeability. However, their efficiency is often limited by poor water solubility. Thus, there is a special need for bioenhancers of naturally derived compounds. In this review we present the potential of cyclodextrin nanosponges (CDNSs) as bioavailability enhancers of selected phytochemicals, namely curcumin, resveratrol, oxyresveratrol and quercetin whose very poor water solubility is the biggest obstacle to high efficiency.