In vitro Digestion and Swelling Kinetics of Thymoquinone-Loaded Pickering Emulsions Incorporated in Alginate-Chitosan Hydrogel Beads.

See Kiat Wong,Cheng Heng Pang,Siah Ying Tang,Tin Wui Wong,Bey Hing Goh,Sivakumar Manickam,Dora Lawrencia,Janarthanan Supramaniam

doi:10.3389/fnut.2021.752207

Abstract

The present work aimed to investigate the swelling behavior, in vitro digestion, and release of a hydrophobic bioactive compound, thymoquinone (TQ), loaded in Pickering emulsion incorporated in alginate-chitosan hydrogel beads using a simulated gastrointestinal model. In this study, oil-in-water Pickering emulsions of uniform micron droplet sizes were formulated using 20% red palm olein and 0.5% (w/v) cellulose nanocrystals-soy protein isolate (CNC/SPI) complex followed by encapsulation within beads. FT-IR was used to characterize the bonding between the alginate, chitosan, and Pickering emulsion. 2% (w/v) alginate-1% (w/v) chitosan hydrogel beads were found to be spherical with higher stability against structural deformation. The alginate-chitosan beads displayed excellent stability in simulated gastric fluid (SGF) with a low water uptake of ~19%. The hydrogel beads demonstrated a high swelling degree (85%) with a superior water uptake capacity of ~593% during intestinal digestion in simulated intestinal fluid (SIF). After exposure to SIF, the microstructure transformation was observed, causing erosion and degradation of alginate/chitosan wall materials. The release profile of TQ up to 83% was achieved in intestinal digestion, and the release behavior was dominated by diffusion via the bead swelling process. These results provided useful insight into the design of food-grade colloidal delivery systems using protein-polysaccharide complex-stabilized Pickering emulsions incorporated in alginate-chitosan hydrogel beads.

Highlights

Thymoquinone (TQ), a major essential oil component of Nigella sativa seeds, has attracted significant attention in recent years to be used as an alternative to chemical drugs
The cellulose nanocrystals-soy protein isolate (CNC/Soy protein isolate (SPI)) complex was used as the Pickering stabilizer and dispersed in the aqueous phase
The alginate-chitosan (Alg-Chi) hydrogel beads were prepared by external gelation method through dripping a mixture of TQ-loaded CNC/SPI-stabilized Pickering emulsion (TPE) with different alginate concentrations into a pre-mixed

Summary

Introduction

Thymoquinone (TQ), a major essential oil component of Nigella sativa seeds, has attracted significant attention in recent years to be used as an alternative to chemical drugs. Several studies showed that TQ could induce apoptosis in human colorectal cancer cells by abrogate the stress response pathway sensor CHEK1 [3] and inhibit the proliferation of human colon cancer cells by increasing the phosphorylation states of the mitogenactivated protein kinases [4, 5] These findings suggest that TQ could be a critical component in formulating nutraceutical food products for colon cancer prevention. Researchers found that TQ suffers from chemical decomposition and enzymatic degradation in the gastrointestinal tract, which further limits the oral administration of TQ [7] These limitations could be effectively overcome by physically entrapping TQ in delivery colloid carrier systems to enhance its bioavailability and therapeutic ability

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Results

Conclusion