Fabrication of Electrospun Eugenol/Cyclodextrin Inclusion Complex Nanofibrous Webs for Enhanced Antioxidant Property, Water Solubility, and High Temperature Stability

In this study, inclusion complexes (IC) of three cyclodextrin derivatives (HP-beta-CD, HP-gamma-CD, and M-beta-CD) with eugenol (essential oil compound) were formed in highly concentrated aqueous solutions and then transformed into self-standing functional nanofibrous webs by electrospinning. The improved aqueous solubility of eugenol was confirmed by phase solubility diagrams, in addition, the phase solubility tests also revealed 1:1 molar ratio complexation between host:guest molecules; CD:eugenol. Even though eugenol has a volatile nature, a large amount of eugenol (similar to 70-95%) was preserved in eugenol/cyclodextrin inclusion complex nanofibrous webs (eugenol/CD/IC-NW). Moreover, enhanced thermal stability of eugenol was recorded for eugenol/CD/IC-NW (up to similar to 310 degrees C) when compared to pure form of eugenol (up to similar to 200 degrees C). The eugenol/CD/IC-NW exhibited fast dissolving behavior in water, contrary to poorly water-soluble eugenol. It was observed that the complexation between M-beta-CD and eugenol was the strongest when compared to other two host CD molecules (HP-beta-CD and HP-gamma-CD) for eugenol/CD/IC-NW samples. The electrospun eugenol/CD/IC-NW samples have shown enhanced antioxidant activity compared to pure form of eugenol. In summary, cyclodextrin inclusion complexes of essential oil compounds, such as eugenol, in the form of self-standing nanofibrous webs may have potentials for food and oral-care applications due to their particularly large surface area along with fast-dissolving character, improved water solubility, high temperature stability, and enhanced antioxidant activity.