Silica-Lipid Hybrid Microparticles as Efficient Vehicles for Enhanced Stability and Bioaccessibility of Curcumin

Abstract

Curcumin is an active ingredient with multiple functions, but its application is often restricted due to its poor water solubility, weak stability, and consequently low bioaccessibility. Based on this, the aim of this work is to develop a new vehicle to overcome these restrictions. Here we developed a curcumin-loaded nanoemulsion and then curcumin-loaded silica-lipid hybrid microparticles through emulsification and vacuum drying, respectively. The loading of curcumin in the nanoemulsion and microparticles was (0.30±0.02) and (0.67±0.02) %, respectively. FTIR and XRD analyses of microparticles revealed that curcumin was encapsulated in porous, amorphous silica. In vitro antioxidant activities showed that the encapsulation would not affect the antioxidant activity of curcumin. In vitro simulated digestion indicated that nanoemulsion and microparticles had higher curcumin bioaccessibility than the control group. The storage stability of microparticles remained the same during 6 weeks in the dark at 4, 25 and 40 °C. Moreover, the microparticles had a better chemical stability than nanoemulsion under the light. The cell viability was over 80% when the concentration of nanocarriers was less than 45 μg/mL. Hence, the microparticles could be a promising means to load curcumin and improve its solubility, light stability and bioaccessibility.

Keywords: antioxidant activity; bioaccessibility; curcumin; silica-lipid hybrid microparticles; storage stability.

Fig. 1

Transmission electron microscopic image of: a) curcumin nanoemulsion, and scanning electron microscopic images of: b) hydrophilic fumed sillica (Aerosil 380), and c) curcumin silica-lipid hybrid microparticles

Fig. 2

The spectra of: a) X-ray diffraction of curcumin, Aerosil 380, physical mixture of curcumin and Aerosil 380, and curcumin silica-lipid hybrid microparticles (Cur-SLH), and b) FTIR of curcumin, blank silica-lipid hybrid microparticles (Blank SLH), physical mixture of curcumin and blank SLH, and Cur-SLH microparticles

Fig. 3

Results of: a) DPPH scavenging activity of curcumin ethanol solution (Cur-EtOH), curcumin nanoemulsion (Cur-NE) and curcumin silica-lipid hybrid microparticles (Cur-SLH). Results are shown as mean value±S.D. (N=3), and b) TBARS inhibition by Cur-EtOH, Cur-NE and Cur-SLH. Results are shown as mean value±S.D. (N=3)

Fig. 4

Results show: a) particle size of curcumin nanoemulsion (Cur--NE) and curcumin silica-lipid hybrid microparticles (Cur-SLH) before digestion in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Results are shown as mean value±S.D. (N=3). Different symbols mean significant difference (p≤0.01), b) cumulative FFA released by Cur-NE and Cur-SLH during the simulated gastric digestion. Results are shown as mean value±S.D. (N=3), and c) bioaccessibility of curcumin from Cur-CMC-Na suspension (as a control group), Cur--NE and Cur-SLH after the simulated digestion. Results are shown as mean value±S.D. (N=3). ***Significantly different (p≤0.01)

Fig. 5

Retention ratios of curcumin in: a) curcumin nanoemulsion (Cur-NE), b) curcumin silica-lipid hybrid microparticles (Cur-SLH) during storage for 6 weeks at 4, 25 and 40 °C in the dark, and c) curcumin in ethanol solution (Cur-EtOH), Cur-NE and Cur-SLH during storage for 6 weeks at 25 °C under light. Results are shown as mean value±S.D. (N=3)

Fig. 6

Cell viability of curcumin nanoemulsion (Cur-NE), blank nanoemulsion (Blank-NE), curcumin silica-lipid hybrid microparticles (Cur--SLH) and blank silica-lipid hybrid microparticles (Blank-SLH). Results are shown as mean value±S.D. (N=3)