Interactions between ZnO Nanoparticles and Polyphenols Affect Biological Responses

Effects of the Interactions Between Food Additive Titanium Dioxide and Matrices on Genotoxicity

Titanium dioxide (TiO2), a white color food additive, is widely used in bakery products, candies, chewing gums, soups, and creamers. Concerns about its potential genotoxicity have recently emerged, particularly following the European Union's ban on its usage as a food additive due to its genotoxicity potential. Conflicting in vitro and in vivo results regarding its genotoxicity highlight the need for further in-depth investigation. Moreover, food additives can interact with food components or biological matrices, potentially altering their biological responses and genotoxicity. In this study, we evaluated the interactions between two different sizes of additive TiO2 particles and food or biological matrices, including albumin, fetal bovine serum (FBS), and glucose. The results showed that the hydrodynamic diameters of TiO2 increased upon interaction with albumin or FBS, but not with glucose. The presence of albumin or FBS reduced TiO2-induced cytotoxicity, oxidative stress, in vitro intestinal transport, and ex vivo intestinal absorption to untreated control levels, regardless of particle size. While TiO2 caused DNA damage in intestinal Caco-2 cells, the interactions with albumin or FBS significantly reduced the DNA damage to levels comparable to untreated controls. The DNA damage was closely related to oxidative stress caused by TiO2. These findings suggest that the interaction of TiO2 with albumin or FBS, resulting in increased hydrodynamic diameters, mitigates its cytotoxicity, oxidative stress, intestinal transport, and genotoxicity. Further investigation is required to fully understand the potential genotoxicity of TiO2 in food contexts.

Stixis scandens leaf extract-loading ZnO nanoparticles for porcine epidemic diarrhea virus (PEDV) treatment

Porcine epidemic diarrhea (PED) is one of the diseases that causes great losses for livestock farmers. Because vaccines against the disease are not very effective, there is a great demand for biological products with effective resistance to PED virus (PEDV). One of the most important trends today is the use of active ingredients from nature in animal husbandry. This study aimed to create an effective agent against PEDV from the extract of Stixis scandens, which has been shown to inhibit PEDV. The aqueous (denoted as TCN) and ethanolic extracts (denoted as TCC) of Stixis scandens leaves were first prepared and then qualitatively analyzed for their chemical compositions. The TCN was used to synthesize ZnO nanoparticles (NPs) at various sizes from 20 to 120 nm. Subsequently, TCC was loaded on ZnO NPs to form ZnO-extract nanoformulations with an extract loading content of 5.8-7.6%. Total polyphenols (TP) and total alkaloids (TA) in TCC were 38.51 ± 0.25 μg GAE per mg and 22.37 ± 0.41 μg AtrE per mg, respectively. TP was less loaded but more released from the nanoformulations than TA. The A1T nanoformulation, containing only 7.6% extract, had a minimum PEDV inhibitory concentration of 3.9 μg mL-1, which was comparable to that of TCC. The experiments confirmed that the nanoformulations are promising for PEDV inhibition applications.

Food Additive Solvents Increase the Dispersion, Solubility, and Cytotoxicity of ZnO Nanoparticles

Zinc oxide (ZnO) nanoparticles (NPs) are utilized as a zinc (Zn) fortifier in processed foods where diverse food additives can be present. Among them, additive solvents may strongly interact with ZnO NPs by changing the dispersion stability in food matrices, which may affect physico-chemical and dissolution properties as well as the cytotoxicity of ZnO NPs. In this study, ZnO NP interactions with representative additive solvents (methanol, glycerin, and propylene glycol) were investigated by measuring the hydrodynamic diameters, solubility, and crystallinity of ZnO NPs. The effects of these interactions on cytotoxicity, cellular uptake, and intestinal transport were also evaluated in human intestinal cells and using in vitro human intestinal transport models. The results revealed that the hydrodynamic diameters of ZnO NPs in glycerin or propylene glycol, but not in methanol, were significantly reduced, which is probably related to their high dispersion and increased solubility under these conditions. These interactions also caused high cell proliferation inhibition, membrane damage, reactive oxygen (ROS) generation, cellular uptake, and intestinal transport. However, the crystal structure of ZnO NPs was not affected by the presence of additive solvents. These findings suggest that the interactions between ZnO NPs and additive solvents could increase the dispersion and solubility of ZnO NPs, consequently leading to small hydrodynamic diameters and different biological responses.