Efficient encapsulation of fat-soluble food-derived biofunctional substances (curcumin as an example) in dual-modified starch-based nanoparticles containing large conjugated systems

Design and fabrication of functionalized curdlan-curcumin delivery system to facilitate the therapeutic effects of curcumin on breast cancer

We developed a facile method for the fabrication of a biodegradable delivery system composed of two blocks: curdlan and curcumin. This was achieved by chemical functionalization of curdlan through tosylation, amination followed by complexation with curcumin. A comprehensive evaluation of structural characterization and component stability showed that cur-cum complex exhibited better anticancer properties with enhanced thermal properties. The cur-cum complex shows pH sensitive sustained release behaviour with higher release at acidic pH and kinetic data of drug release follows the Korsmeyer-Peppas model. The cur-cum complex has ability to block the proliferation of the MCF-7 cell line as revealed by MTT assay which showed increased toxicity of cur-cum complex against these cell lines. The results obtained from western blot analysis demonstrated that the co-administration of cur and cum effectively induced apoptosis in MCF-7 cells. This effect was observed by a considerable upregulation of the Bcl-2/Bax ratio, a decline in mRNA expression of LDHA, level of lactate and LDH activity. The results clearly depict the role of functionalized curdlan as efficient carrier for curcumin delivery with prolonged, sustained release and enhanced bioavailability, thereby improving the overall anticancer activity.

Dual-modified starch as particulate emulsifier for Pickering emulsion: Structure, safety properties, and application for encapsulating curcumin

In this study, cinnamic acid modified acid-ethanol hydrolyzed starch (CAES) with different degrees of substitution (DS) was fabricated to stabilize Pickering emulsions and probed their application for encapsulating curcumin (Cur). Successful preparation of CAES (with DS from 0.016 to 0.191) was confirmed by 1H NMR and FT-IR, and their physicochemical properties were characterized by XRD, SEM, and TGA. The biosafety evaluations and surface wettability confirmed the excellent safety and amphiphilic character of CAES. CAES-stabilized Pickering emulsion (CS-PE) exhibited different emulsion stability at different DS, with CS-PE (0.031) showing the highest stability. CLSM revealed that the CAES (0.031) formed a dense barrier on the surface of the oil droplets, preventing them from coalescing. The CS-PE (0.031) achieved effective encapsulation of Cur (up to 96.2 %). Compared with free Cur, CS-PE (0.031) exhibited better photochemical stability, higher free fatty acids (FFA) release, and enhanced bioaccessibility. These studies suggested that CAES may serve as a promising emulsifier for stabilizing Pickering emulsions to encapsulate and deliver hydrophobic bioactive compounds.

Novel and safe debranched starch-zinc complexes with endoconcave structure as zinc supplements

Zinc deficiency is a serious risk to human health and growth, especially in children. The development of zinc supplements can effectively reduce this harm. Here, a series of debranched starch‑zinc complexes (DS-Zn) were prepared, whose zinc complexation was inversely proportional to the amylopectin content in the debranched starch (DS). The physicochemical properties of DS-Zn were characterized using the conductivity, XRD, iodine staining and thermogravimetry. Combined with XPS, solid-state 13C NMR and IR, it was elucidated that the structure of DS-Zn is endoconcave structure with 2-O and 3-O of DS on the inner side and 6-O of DS on the outer side, where zinc is located. The DS-Zn exhibits good biosafety including blood, cellular and mutagenicity. In vitro simulations of digestion and zinc-deficient cellular models showed that DS-Zn was more tolerant to the gastrointestinal environment and more effective in zinc supplementation (increased by 33 %) than inorganic zinc supplements. Utilizing the compressibility of starch, DS-Zn was prepared as a more palatable oral cartoon tablet for children. This study will provide important support to advance the development and application of novel starch-based zinc nutritional supplements.

Preparation and characterization of fine and stable short amylose nanocarriers for curcumin using a highly efficient and convenient method

To prepare fine and stable nanocarriers for curcumin using a highly efficient and convenient method, nanoprecipitation combined with ultrasonication and a high-speed dispersion (US+HSS) method were used to prepare short amylose nanoparticles with pre-formed helical structures. Their morphology, structural characteristics, and embedding effects for curcumin were investigated. The results showed that the optimal ratio of ethanol to short amylose solution and ultrasonic time was 4:1 and 4 min, respectively. The nanoparticles showed a small size (82.43 nm), relatively high loading capacity (11.57 %), and a peak gelatinization temperature of 97.74 °C. Compared to the nanoprecipitation method, the short amylose nanoparticles prepared using the US+HSS method possessed a higher V-type crystalline structure ratio. In addition, the US+HSS method was easier to use to prepare nanoparticles with high stability against NaCl, and the stable nanoparticles showed the best in vitro sustained release effect for curcumin. The Peppas-Sahlin model was the optimal model that matched curcumin release from nanoparticles during digestion.