Use of α-Cyclodextrin to Produce Nanoencapsulated Curcumin to Preserve Curcumin Stability from Photooxidation While Simultaneously Enhancing Caco-2 Intestinal Uptake and Antioxidant Capacity

Curcumin is a major bioactive component present in turmeric, attributed with a bright yellow color; however, with low solubility and susceptibility to photooxidation, many of the purported health benefits are actually limited. We developed an encapsulation delivery system to produce curcumin nanoparticles using α-cyclodextrin as a carrier and Tween 80 as a surfactant for the purpose of increasing photostability and bioavailability. We used RSM to determine an optimal curcumin nanoparticle (NP) size of 386.4 ± 21.3 nm and entrapment efficiency of 97.4 ± 2.9% for use in functional tests conducted in differentiated Caco-2 cells. Curcumin-NP showed greater (p = 0.001) (74.32 ± 4.20%) stability compared to free curcumin (36.74 ± 3.03%), after treatment with pulsed light, at the highest 20 J/cm2 energy input. The release behavior of curcumin-NPs was pH-dependent and showed a 5 times higher intestinal epithelial cellular uptake and 21.3% decrease of TEER-value, compared to free curcumin (p = 0.017). Compared with free curcumin, the curcumin-NPs had higher antioxidant capacity in all tests while exhibited lower antioxidant capacity loss after pulsed light treatment. Moreover, pre-exposure of curcumin-NPs to pulsed light treatment showed no apparent cytotoxicity effects in Caco-2 cells. In conclusion, using α-cyclodextrin for curcumin-NP encapsulation enhanced both bioavailability and photostability, leading to greater intestinal intracellular antioxidant capacity and no loss in cell viability.