Ginger Extract Suppresses Inflammatory Response and Maintains Barrier Function in Human Colonic Epithelial Caco‐2 Cells Exposed to Inflammatory Mediators

The beneficial effects of ginger in the management of gastrointestinal disturbances have been reported. In this study, the anti‐inflammatory potential of ginger extract was assessed in a cellular model of gut inflammation. In addition, the effects of ginger extract and its major active compounds on intestinal barrier function were evaluated. The response of Caco‐2 cells following exposure to a mixture of inflammatory mediators [interleukin [IL]‐1β, 25 ng/mL; lipopolysaccharides [LPS], 10 ng/mL; tumor necrosis factor [TNF]‐α, 50 ng/mL; and interferon [INF]‐γ, 50 ng/mL] were assessed by measuring the levels of secreted IL‐6 and IL‐8. In addition, the mRNA levels of cyclooxygenase‐2 and inducible nitric oxide synthase were measured. Moreover, the degree of nuclear factor (NF)‐κB inhibition was examined, and the intestinal barrier function was determined by measuring the transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)‐dextran transfer. It was observed that ginger extract and its constituents improved inflammatory responses by decreasing the levels of nitrite, PGE2, IL‐6, and IL‐8 via NF‐κB inhibition. The ginger extract also increased the TEER and decreased the transfer of FITC‐dextran from the apical side of the epithelium to the basolateral side. Taken together, these results show that ginger extract may be developed as a functional food for the maintenance of gastrointestinal health.     

Esterification of Quercetin Increases Its Transport Across Human Caco‐2 Cells

Plant polyphenols showed useful biochemical characteristics in vitro; however, the assessments of their clinical applications in vivo are restricted by their limited bioavailability due to their strong resistance to 1st‐pass effects during absorption. In order to improve the bioavailability of quercetin (QU), the ester derivative of QU (3,3′,4′,5,7‐pentahydroxy flavones, TAQU) was synthesized, followed by examining the oil–water partition coefficient as well as the transport mechanisms of QU and its ester derivative (TAQU) using human Caco‐2 cells. The transport characteristics of QU and TAQU transport under different conditions (different concentrations, time, pH, temperature, tight junctions, and potential transporters) were systematically investigated. Results showed that QU had a lower permeability coefficient (2.82 × 10^?6 cm/s) for apical‐to‐basolateral (AP‐BL) transport over 5 to 50 μM, whereas the transport rate for AP to BL flux of TAQU (5.23 × 10^?6 cm/s) was significantly greater than that of QU. Paracellular pathways were not involved during the transport of both QU and TAQU. QU was poorly absorbed by active transport, whereas TAQU was mostly absorbed by passive diffusion. Efflux transporters, P‐glycoproteins, multidrug resistance proteins were proven to participate in the transport process of QU, but not in that of TAQU. These results suggested that improving the lipophicity of QU by esterification could increase the transport of QU across Caco‐2 cells.     

Bioavailability of iron from a heat treated glucose‐lysine model food system: assays in rats and in Caco‐2 cells

The influence of Maillard reaction products (MRP) from glucose–lysine on iron bioavailability was investigated. Equimolar glucose–lysine mixtures (GL, 40% moisture) were heated (150 °C, for 30, 60 and 90 min) to prepare samples GL30, GL60 and GL90, respectively, and were used to study the influence of MRP on iron solubility, iron uptake and transport in Caco‐2 cells and iron balance in rats. After an initial increase with GL30, in vitro iron solubility decreased in the presence of most of the heated samples. The Caco‐2 cell experiments showed that Fe cell content increased in the presence of heated mixtures with respect to GL, whereas transport was less affected. Iron balance was determined in rats fed diets containing the GL30 and GL90 samples (3%) for a 21 day period and compared with that measured in a control group. Consumption of glucose–lysine heated mixtures increased total iron retention, although hemoglobin values decreased. Iron accumulations in organs such as the spleen, kidney and small intestine were observed. Copyright © 2004 Society of Chemical Industry     

Development of a three‐tier in vitro system,using Caco‐2 cells,to assess the effects of lactate on iron uptake and transport from rye bread following in vitro digestion

A three‐tier Caco‐2 cell system was developed to assess simultaneously iron dialysability, uptake and transport across the Caco‐2 monolayer from an in vitro digested food matrix. The effect of lactate (0–200 mmol L⁻¹) on iron absorption from rye bread subjected to simulated peptic (pH 5.5) and pancreatic digestion (pH 6.5) was investigated to model absorption pre and post the sphincter of Oddi. Lactate increased dialysability (11.8%, P < 0.05) in peptic digests whereas it reduced it in pancreatic digests (4.9%, P < 0.001). Iron uptake from the peptic digests was in the region of 39–76 pmol mg⁻¹ protein whereas it decreased from 281 to 51 pmol mg⁻¹ protein in pancreatic digests. Iron transport was calculated for the peptic digests from [¹⁴C]polyethylene glycol movement and only at 200 mmol L⁻¹ lactate was there any detectable transcellular transport (180 pmol mg⁻¹ protein, P < 0.05). Iron absorption was positively correlated to dialysable iron for both digests (R² = 0.48 and 0.41, respectively, P < 0.01) and the effect of lactate was therefore associated mainly with iron bioaccessibility. The three‐tier system showed the potential to obtain detailed insight into each step involved in iron transport across the monolayer from a food mixture. Copyright © 2006 Society of Chemical Industry     

‘平阳黄汤’对高脂饮食大鼠肠道屏障和肠道菌群的影响

为探讨‘平阳黄汤’对高脂饮食大鼠的肥胖调控作用及其与肠道屏障和菌群的关系,将SD雄性大鼠分为正常饮食组、高脂饮食组以及平阳黄汤低、中、高剂量组（75、150、300 mg/kg mb）,建立预防肥胖模型。通过分析大鼠体质量变化、摄食量、脂肪指数、血清指标、肝脏指标和肝脏、结肠组织切片评估‘平阳黄汤’对高脂饮食大鼠的肥胖调控作用;通过分析肠道的病理形态、杯状细胞数量和紧密连接蛋白的表达评估肠道屏障作用;通过分析微生物多样性和菌群结构评估对肠道菌群的影响。结果：高剂量‘平阳黄汤’能极显著降低高脂饮食大鼠的体质量增长量、附睾和肾周脂肪质量（P＜0.01）,降低血清血脂、脂肪因子和氧化应激水平（P＜0.01）,降低肝脏甘油三酯和总胆固醇水平（P＜0.01）,有效调节肝脏的脂质堆积和炎症损伤。同时,高剂量平阳黄汤还显著改善了高脂饮食大鼠结肠的形态,减少绒毛脱落和炎症浸润现象,显著恢复肠道杯状细胞数量,提高闭锁小带蛋白和闭锁蛋白的表达（P＜0.01）,有效降低了血清中脂多糖、肿瘤坏死因子α和白细胞介素6水平（P＜0.01）,有效预防代谢性内毒素和全身慢性炎症,提高了大鼠肠道菌群的丰度和多样性,促进了与肥胖发生相关有益菌的增殖,抑制有害菌的生长。结论：‘平阳黄汤’能通过维护肠道屏障和调节肠道菌群紊乱,有效调控高脂饮食引起的肥胖。     

燕麦β-葡聚糖对2型糖尿病大鼠肠黏膜屏障的影响

目的:探究燕麦β-葡聚糖对2型糖尿病大鼠肠黏膜屏障的影响。方法:雄性SD大鼠高脂饲料喂养4周,腹腔注射链脲佐菌素(streptozotocin,STZ)建立2型糖尿病模型,成模后随机分为模型对照组和燕麦β-葡聚糖低、中、高剂量组。低、中、高剂量组由基础饲料添加燕麦β-葡聚糖至其质量分数分别为0.275%、0.550%、1.100%,模型对照组和正常对照组均以基础饲料喂养。10周后,测定其空腹血糖、肠道菌群以及结肠β-防御素-2、分泌型免疫球蛋白A(secretory immunoglobulin A,s Ig A)、紧密连接蛋白Occludin含量。结果:高剂量组较模型对照组血糖水平显著降低(P0.05);燕麦β-葡聚糖各干预组结肠紧密连接蛋白Occludin的表达水平显著高于模型对照组(P0.05),β-防御素-2水平显著低于模型对照组(P0.05),结肠s Ig A水平与模型对照组之间的差异不显著(P0.05);中、高剂量组结肠大肠杆菌数量上升幅度减小(P0.05),燕麦β-葡聚糖各干预组双歧杆菌、乳酸杆菌数量上升幅度增大(P0.05)。结论:燕麦β-葡聚糖可以改善2型糖尿病大鼠肠黏膜机械屏障和生物屏障的损伤,起到保护肠黏膜屏障的作用。     

Modified Dietary Fiber from Cassava Pulp and Assessment of Mercury Bioaccessibility and Intestinal Uptake Using an In Vitro Digestion/Caco‐2 Model System

The ability of modified dietary fiber (MDF) generated from cassava pulp to modulate the bioaccessibility and intestinal absorption of heavy metals may be helpful to mitigate health risk associated with select foods including select fish high in methyl mercury. Using a coupled in vitro digestion/Caco‐2 human intestinal cell model, the reduction of fish mercury bioaccessibility and intestinal uptake by MDF was investiaged. MDF was prepared from cassava pulp, a byproduct of tapioca production. The highest yield (79.68%) of MDF was obtained by enzymatic digestion with 0.1% α‐amylase (w/v), 0.1% amyloglucosidase (v/v) and 1% neutrase (v/v). MDF and fish tissue were subjected to in vitro digestion and results suggest that MDF may reduce mercury bioaccessibility from fish to 34% to 85% compared to control in a dose‐dependent manner. Additionally, accumulation of mercury from digesta containing fish and MDF was only modestly impacted by the presence of MDF. In conclusion, MDF prepared from cassava pulp may be useful as an ingredient to reduce mercury bioavailability from food such as fish specifically by inhibiting mercury transfer to the bioaccessibile fraction during digestion.     

Bioavailability Assessment of Copper,Iron, Manganese,Molybdenum, Selenium,and Zinc from Selenium‐Enriched Lettuce

Cu, Fe, Mn, Mo, Selenium (Se), and Zn bioavailability from selenate‐ and selenite‐enriched lettuce plants was studied by in vitro gastrointestinal digestion followed by an assay with Caco‐2 cells. The plants were cultivated in the absence and presence of two concentrations (25 and 40 µmol/L of Se). After 28 days of cultivation, the plants were harvested, dried, and evaluated regarding the total concentration, bioaccessibility, and bioavailability of the analytes. The results showed that biofortification with selenate leads to higher Se absorption by the plant than biofortification with selenite. For the other nutrients, Mo showed high accumulation in the plants of selenate assays, and the presence of any Se species led to a reduction of the plant uptake of Cu and Fe. The accumulation of Zn and Mn was not strongly influenced by the presence of any Se species. The bioaccessibility values were approximately 71%, 10%, 52%, 84%, 71%, and 86% for Cu, Fe, Mn, Mo, Se, and Zn, respectively, and the contribution of the biofortified lettuce to the ingestion of these minerals is very small (except for Se and Mo). Due to the low concentrations of elements from digested plants, it was not possible to estimate the bioavailability for some elements, and for Mo and Zn, the values are below 6.9% and 3.4% of the total concentration, respectively. For Se, the bioavailability was greater for selenite‐enriched than selenate‐enriched plants (22% and 6.0%, respectively), because selenite is biotransformed by the plant to organic forms that are better assimilated by the cells.     

Bioavailability of zinc from infant foods by in vitro methods (solubility,dialyzability and uptake and transport by Caco‐2 cells)

The aim of this study was to evaluate the bioavailability of zinc from infant foods (adapted, follow‐up and toddler milk‐based formulas and fruit juices containing milk and cereals, FMC) using solubility, dialyzability and a model combining simulated gastrointestinal digestion and zinc uptake and transport by Caco‐2 cells. The greater solubility of zinc from infant formulas compared with fruit juices (FMC) could be due to the greater casein phosphopeptide content resulting from casein hydrolysis. The highest zinc dialysis percentage corresponded to FMC, which on the other hand had the lowest zinc contents of the analyzed samples. The presence of organic acids in samples of this kind favors the formation of soluble low molecular weight complexes with zinc, thereby increasing the solubility of the latter. Bifidobacterium addition exerted no effect upon zinc bioavailability. Transport and uptake efficiency in Caco‐2 cells were significantly greater for toddler formulas, which presented the highest casein contents. The greater efficiency in zinc transport and uptake from the powdered toddler formula compared with the liquid formulation could be explained by the effect of Maillard reaction products. Copyright © 2006 Society of Chemical Industry     

红枣多糖对小鼠肠道免疫屏障的保护作用及机制研究

目的：研究红枣多糖（Jujube Polysaccharides,JPS）对小鼠肠道免疫屏障的保护作用及其机制。方法：将70只雄性ICR小鼠随机分为5组：阴性对照组、模型组、JPS低（150 mg/kg·bw）、中（300 mg/kg·bw）、高（600 mg/kg·bw）剂量组,连续灌胃28 d,第28 d采用腹腔注射环磷酰胺造模。研究JPS对免疫抑制小鼠免疫器官指数、肠道派伊尔结数量、肠道免疫相关指标、肠道免疫细胞数量和肠道免疫相关蛋白表达的影响。结果：JPS能够保护小鼠肠黏膜的正常形态结构,增加小鼠免疫器官指数和派伊尔结数量,增加肠道分泌的免疫球蛋白A和分泌型免疫球蛋白A的含量,增强肠道溶菌酶和酸性磷酸酯酶的活性,增加肠道免疫细胞的数量,下调肠道MyD88、NF-κB p65、IL-1β蛋白表达。结论：JPS对小鼠的肠道免疫屏障具有保护作用,其机制与调节MyD88/NF-κB途径相关蛋白表达有关。     

Assessment of iron bioavailability from twenty elite late‐maturing tropical maize varieties using an in vitro digestion/Caco‐2 cell model

An in vitro digestion/Caco‐2 cell model was used to assess iron bioavailability of twenty elite late‐maturing tropical maize varieties grown in three diverse agroecologies in West and Central Africa (WCA). Kernel‐iron concentration of the varieties, averaged across locations, varied from 19.2 to 24.4 mg kg^?1, while mean kernel‐zinc concentration ranged between 19.4 and 24.6 mg kg^?1. Significant differences in iron bioavailability were observed among varieties, but the environment had no significant effect. Mean bioavailable iron ranged between 14% below and 43% above the reference control variety, TZB‐SR. Variety DMR‐LSR‐Y with the highest concentrations of kernel‐iron and ‐zinc of 24–25 mg kg^?1 across the three locations had a similar quantity of bioavailable iron as the reference control, TZB‐SR. In the long run this variety could be potentially effective in reducing iron deficiency because of its high kernel‐iron. The most promising varieties were Mid‐altitude STR synthetic and ACR91SUWAN‐1‐SRC1. They had kernel‐iron and ‐zinc levels of 22–24 mg kg^?1 and bioavailable iron 24–36% higher than the reference control, TZB‐SR. Additional research is necessary to determine if the increases in kernel‐iron concentration and bioavailable iron observed in this study can significantly improve the iron status of individuals in WCA at risk for iron deficiency. Copyright © 2004 Society of Chemical Industry     

基于肠道吸收机制的膳食多酚代谢研究进展

膳食多酚是植物性食物的重要成分,不仅与食品的风味和颜色等品质直接相关,还有利于人体健康。由于它们在基质释放、消化、吸收、代谢和组织分布期间发生改变,使得各种酚类化合物生物利用度有一定的差异。饮食中含量最丰富的不一定具有最佳生物利用度,多酚的吸收转化及生物利用度是多酚生物活性主要研究热点之一。本文以多酚肠道吸收机制为基点,综述了膳食多酚在胃肠道释放、吸收、代谢等过程,以期为多酚类保健食品的研发提供依据。