Cyclodextrins-based nanocomplexes for encapsulation of bioactive compounds in food, cosmetics, and pharmaceutical products: principles of supramolecular complexes formation, their influence on the antioxidative properties of target chemicals, and recent advances in selected industrial applications

Abstract Cyclodextrins (CDs) are a group of toroidal oligosaccharides that contribute to several guest-associated phenomena in gas or liquid phases. For over 100 years these macrocycles have been of interest in both pure research as well as applied technologies. The host–guest nanocapsulation of low-molecular-mass compounds with cyclodextrins (host and guest molecules, respectively) is highly molecular shape selective and in modern analytical chemistry is the method of choice for resolution of various isomers, including enantiomers. Particularly, in separation systems involving liquid mobile phases, cyclodextrins are frequently used as very efficient chiral and nonchiral selectors. CD modification of stationary phase allows enantiomers separation by gas chromatographic techniques. Over the past few decades these compounds have found a wide range of applications, in pharmacy, cosmetology, analytical, and food chemistry. The polar/nonpolar nature of cyclodextrins results in that compounds capsulated within CD cavity are characterized by different physicochemical properties than the free ones. CDs are commonly used to (1) increase the solubility of included compounds; (2) stabilize oxygen sensitive substances; (3) stabilize highly volatile compounds, enabling easy storage or transport; (4) dispose of toxins; (5) modify the chemical reactivity of the included substance and change its physicochemical and/or biomedical properties (mask of color, unpleasant odor or taste); as well as (6) reduce the adverse effects of drugs. Inclusion phenomena can be studied using UV-Vis, IR, NMR, cyclic or differential pulse voltammetry. In cosmetology CDs are used to change the volatility of the target substances, particularly for maintaining longer aroma of the commercial products, removing unwanted odors, or releasing the active substances to the nails or skin. Practical applications in agriculture and environment include the delay of germination in seeds/potatoes and removing of heavy metals and organic micropollutants. By complexation of nonpolar molecules, CDs increase bioavailability of pharmaceutical formulations, especially drugs that are nonsoluble in pure water steroids. In the food industry cyclodextrins are used as stabilizers for butter, margarine, mayonnaise, or garlic dry extracts. This chapter summarizes the literature concerning general information about cyclodextrins and related macrocycles, their supramolecular nano-complexes with low-molecular mass compounds, physicochemical properties of host–guest complexes, encapsulation of bioactive target components in food and cosmetics products as well as pharmaceutical formulations, based on the research communications, mainly published over a period of the last 3 years (2012–15). Moreover, the research dealing with the influence of encapsulated target compounds by CDs on their antioxidant properties is discussed. Some aspects of antioxidants analysis and preservation of such chemicals in complex samples in the presence of macrocyclic additives as well as quantitative analysis of free radicals and radicals scavengers is presented from a practical point of view. In addition, a review concerning the use of macrocyclic nano-additives as an ingredient of food, pharmaceutical formulations, cosmetics, and related products that are considered theoretically as well as currently on the market is reported.