Bioavailability enhancement of hydrophobic nutraceuticals using γ-cyclodextrin

Natural hydrophobic bioactives that possess human health benefits often have undesirable characteristics that limit their use as nutraceuticals. These bioactives are usually unstable in the presence of oxygen, ultraviolet radiation, and heat. Furthermore, their solubility in water is low owing to their hydrophobicity or instability, which leads to low bioavailability. Much attention has recently been directed to the use of cyclodextrins (CDs) as complementary and alternative medicinal foods with human health benefits for the current aging population. Systematic studies have been performed to investigate improvements in the stability, water solubility, and bioavailability of hydrophobic nutraceuticals through complexation with CDs. Although hydrophobic nutraceuticals, such as coenzyme Q10, curcumin, and tocotrienol, form insoluble complexes with γ-CD, the bioavailability of the complex dramatically improves compared with conventional technologies. Recently, it was found that hydrophobic bioactives generally aggregate in water, but the dissociated bioactives from γ-CD are captured by bile acid to form micelles without aggregation; thus, both solubility and bioavailability are enhanced. Complexation with γ-CD is a promising method to achieve enhanced bioavailability of hydrophobic nutraceuticals. In this article, an outline of the innovative nanotechnologies that implement γ-CD to enhance stability and control of the solubility and bioavailability of key ingredients for health and beauty in the field of medicinal foods is presented.