Structural Design of Oleogel‐Hydrogel Bigels for Co‐Delivery of Curcumin and Epigallocatechin Gallate with Synergistic Stability and Bioactivity

Abstract Bigels are novel biphasic systems containing hydrogel and oleogel structures, which are designed to deliver multiple bioactives for synergistic activity. The current study develops bigels based on a carrageenan hydrogel and a monoglyceride (GMS) oleogel. Results show that the microstructures of bigels are facilely modified by two surface active ingredients (Tween 20 and polyglycerol polyricinoleate), which then influence the microstructures of the bigels. When curcumin and epigallocatechin gallate (EGCG) are delivered simultaneously, the bioactives work synergistically to slow thermal degradation. Simulated digestion tests indicate that the bigel structures can delay the release of the two bioactives in artificial saliva and simulated gastric fluid (SGF), and allow fast release in simulated intestinal fluid (SIF). DPPH and ABTS tests show the digested Tween 20 bigels containing EGCG and curcumin present synergistic antioxidant activity. Anticancer activity is evaluated in human colon adenocarcinoma HCT116, and the two bioactives work cooperatively to lower cell viability. The bioactives released from Tween 20 bigels have higher cytotoxicity than those from polyglycerol polyricinoleate bigels. The results reveal that facile structural design of bigels has the potential to achieve synergistic stability and bioactivity of co‐delivered bioactives, which is meaningful for the development of functional pharmaceutical, cosmetic, and food products.