Niosomes Consisting of Tween-60 and Cholesterol Improve the Chemical Stability and Antioxidant Activity of (−)-Epigallocatechin Gallate under Intestinal Tract Conditions

In order to improve the chemical stability and antioxidant activity of (−)-epigallocatechin gallate (EGCG) in the gastrointestinal tract, niosomes composed of Tween-60 and cholesterol were developed to encapsulate EGCG in this investigation. EGCG loaded niosomes with encapsulation efficiency around 76% exhibited a small <i>Z</i>-average diameter about 60 nm. Compared to free EGCG, the EGCG remaining in dialysis tubes was significantly improved for niosomes at pH 2 and 7.4. Meanwhile, the residual EGCG for niosomes increased from 3% to 49% after 2 h incubation in simulated intestinal fluid (SIF). Pancreatin was found to impact the stability of niosomes in SIF mainly. Furthermore, the results from ferric reducing antioxidant power and cellular antioxidant activity tests indicated that EGCG loaded niosomes exhibited stronger antioxidant ability than free EGCG during intestinal digestion. Thus, we can infer that niosomal encapsulation might be a promising approach to improve the oral bioavailability of EGCG in the body

Cellular Uptake of β‑Carotene from Protein Stabilized Solid Lipid Nanoparticles Prepared by Homogenization–Evaporation Method

With a homogenization–evaporation method, β-carotene (BC) loaded nanoparticles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, <i>in vitro</i> cytotoxicity, and cellular uptake by Caco-2 cells. The particle diameters of the BC loaded nanoparticles with 0.75% SC or 1.0% WPI emulsifiers were 75 and 90 nm, respectively. Mean particle diameters of three BC loaded nanoparticle nanoemulsions increased less than 10% at 4 °C while they increased more at 25 °C (10–76%) during 30 days of storage. The oxidative stability of BC loaded nanoparticles encapsulated by proteins decreased in the following order: SC > WPI > SPI. The retention rates of BC in nanoparticles were 63.5%, 60.5%, and 41.8% for SC, WPI, and SPI, respectively, after 30 days of storage at 25 °C. The BC’s chemical stability was improved by increasing the concentration of protein. Both the rate of particle growth and the total BC loss at 25 °C were larger than at 4 °C. The color of BC loaded nanoparticles decreased with increasing storage in the dark without oxygen, similar to the decrease in BC content of nanoparticles at 4 and 25 °C. Almost no cytotoxicity due to BC loaded nanoparticles cellular uptake was observed, especially when diluted 10 times or more. The uptake of BC was significantly improved through nanoparticle delivery systems by 2.6-, 3.4-, and 1.7-fold increase, respectively, for SC, WPI, and SPI, as compared to the free BC. The results of this study indicate that protein stabilized, BC loaded nanoparticles can improve stability and uptake of BC

Physical and Antimicrobial Properties of Peppermint Oil Nanoemulsions

The mixture of peppermint oil (PO) with medium-chain triacylglycerol was emulsified in water and stabilized with a food-grade biopolymer, modified starch, to form PO nanoemulsions. The effects of emulsifying conditions including homogenization pressure, the number of processing cycles, and oil loading on the mean diameters and viscosities of nanoemulsions were characterized by dynamic light scattering, optical microscopy, and rheological measurements. The formulated PO nanoemulsions with mean diameters normally <200 nm showed high stability over at least 30 days of storage time. Their antimicrobial properties related to those of PO have also been evaluated by two assays, the minimum inhibitory concentration (MIC) and time-kill dynamic processes, against two Gram-positive bacterial strains of Listeria monocytogenes Scott A and Staphylococcus aureus ATCC 25923. Compared with bulk PO, the PO nanoemulsions showed prolonged antibacterial activities. The results suggest that the nanoemulsion technology can provide novel applications of essential oils in extending the shelf life of aqueous food products

Rosiglitazone inhibits NF-κB-DNA binding activity.

<p>(A) HK-2 cells were pretreated with 10 µM rosiglitazone in the absence or presence of 100 µM GW9662 for 2 hours and then treated with 1 μg/ml LPS for 30 minutes. Equal amounts of nuclear extracts were assayed for binding a biotin-labeled double-stranded NF-κB oligonucleotide as described in 'Material and Methods'. The positions of NF-κB p65 was indicated. The column bar graph shows the means ± SD of values obtained by EMSAs densitometric analysis from three independent experiments. *<i>P</i><0.05 compared to the control group; ^<i>#</i><i>P</i><0.05 compared to the LPS-treated group; ^<i>&</i><i>P</i><0.05 compared to LPS + RGL (10 µM)-treated group.</p

Rosiglitazone inhibits IL-8 and MCP-1 production via a PPARγ-dependent mechanism in LPS-stimulated HK-2 cells.

<p>(A, B) HK-2 cells were pretreated with rosiglitazone (5, 10, 20 µM) in the absence or presence of GW9662 (10, 30, 100 µM) for 2 hours and then treated with 1 μg/ml LPS for 4 hours. IL-8 and MCP-1 mRNA was analyzed by real-time PCR. (C, D) HK-2 cell were pretreated with 10 µM rosiglitazone in the absence or presence of 100 µM GW9662 for 2 hours and then treated with 1 μg/ml LPS for 24 hours. IL-8 and MCP-1 protein in cell supernatants was measured by ELISA. Results are shown as mean ± SD and representative of three independent experiments. *<i>P</i><0.05 compared to the control group; ^<i>#</i><i>P</i><0.05 compared to the LPS-treated group; ^<i>&</i><i>P</i><0.05 compared to LPS + RGL (10 µM)-treated group. </p

RGL inhibits LPS-induced IL-8 and MCP-1 expression in a NCoR-dependent manner.

<p>HK-2 cells were transfected with siNCoR to knock down NCoR, or transfected with sicontrol as controls. Two days after transfection, IL-8 and MCP-1 mRNA were quantified after incubated without or with 10 µM RGL for 2 hours followed by stimulation with 1 μg/ml LPS for 4 hours in HK-2 cells and HK-2/NCoR-knockdown cells. (A) Knockdown efficience of NCoR mRNA by siRNA. (B) The expression of IL-8 mRNA in different groups. (C) The expression of MCP-1 mRNA in different groups. The results are representative of three independent experiments. *<i>P</i><0.05 compared to the control group; ^<i>#</i><i>P</i><0.05 compared to the LPS-treated group.</p

Cytotoxic assessment of RGL in HK-2 cells.

<p>HK-2 cells were treated with the indicated concentrations of RGL (0, 5, 10 , 20 μM) for 24 hours with or without 1 μg/ml LPS. HK-2 cells viability was assessed using an MTT assay, and the surviving cell values are expressed as a percent of control treated cells (no addition of RGL). Each value indicates the mean ± SD from three independent experiments.</p

Rosiglitazone fails to reverse LPS-induced NF-κB nuclear translocation.

<p>HK-2 cells were treated without or with 10 µM RGL for 2 hours and then stimulation with 1 μg/ml LPS for 30 minutes. Nuclear protein was extracted for immunoblotting or cells was processed for immunofluorescent staining as described in 'Material and Methods'. (A) Relative levels of p50 and p65 in nucleus are determined by densitometric analysis and are presented as the relative ratio of LaminB, respectively. The 2 lanes for the same group in the blot represent duplicate experiments. The column bar graph shows the means ±SD of values obtained by densitometric analysis of three independent experiments. *<i>P</i><0.05 compared to the control group. (B) Immunofluorescent staining shows that NF-κB p65 translocated into nucleus after treatment of 1 μg/ml LPS for 30 minutes and pretreatment of 10 µM RGL fialed to antagonize p65 nuclear translocation (Original magnification × 400). </p

SUMOylation of PPARγ by RGL antagonizes LPS-induced chemokine expression and NCoR degradation.

<p>HK-2 cells were transfected with siPIAS1 to knock down PIAS1, or transfected with sicontrol as controls. Two days after transfection, IL-8 and MCP-1 mRNA were quantified after incubated with 10 µM RGL for 2 hours followed by stimulation with LPS 1 μg/ml for 4 hours in HK-2 cells and HK-2/PIAS1-knockdown cells. Quantification of mRNA level was performed by real-time PCR. (A) Knockdown efficience of PIAS1 mRNA by siRNA. (B) The expression of IL-8 mRNA in different groups. (C) The expression of MCP-1 mRNA in different groups. (D) Two days after transfection, Nuclear protein was extracted after incubated with 10 µM RGL for 2 hours followed by stimulation with 1 μg/ml LPS for 30 minutes in HK-2 cells. NCoR protein were quantitated by immunoblotting analysis in different groups. The results are representative of three independent experiments. *<i>P</i><0.05 compared to the control group; ^<i>#</i><i>P</i><0.05 compared to the LPS-treated group. </p

Rosiglitazone inhibits NF-κB binding in IL-8/MCP-1 promoters.

<p>HK-2 cells were treated without or with 10 µM RGL for 2 hours and then stimulation with 1 μg/ml LPS for 60 minutes. The representative agarose gel show PCR products of DNA obtained after chromatin immunoprecipitation with anti-p65 antibody (IP:anti-p65), non -immunoprecipitated DNA (input), or normal mouse IgG (negative control) amplified with primers specific for NF-κB site in IL-8/MCP-1 promoter. </p