Maillard reaction is a nonenzymatic reaction between an amino acid and a reducing sugar that usually occurs upon heating. This reaction occurs routinely in cooking and its products are considered as safe materials. In this study, various MRPs samples were prepared from three different amino acids (lysine, arginine and glycine) and sugars (glucose, fructose and galactose) for 1 h heating at 121¡É. Treatments with the MRPs samples on RAW264.7 cells stimulated with lipopolysaccharide (LPS) decrease nitric oxide (NO) expression compared to control. Moreover, a MRPs sample derived from lysine and galactose most significantly inhibited NO expression. We also evaluated antiinflammatory effect of MRPs with a co‐culture system consisting of Caco‐2 intestinal epithelial cell line (apical side) and RAW264.7 macrophage cell line (basolateral side) to investigate the gut inflammation reaction. In this system, RAW264.7 cells stimulated with LPS decreased transepithelial electrical resistance (TEER), which is a marker of the integrity of cells, and increased TNF‐α productions and gene expressions of IL‐8 and IL‐1¥â in Caco‐2 cells. In this system, ultrafiltration fractions with high molecular weight suppressed IL‐8 gene expression as well as reduction of TNF‐α production from RAW264.7 cells stimulated with LPS.

Proteins and reducing sugars can be conjugated by glycation reaction which is Maillard reaction. We have tried to find a new functional material through this reaction. In the previous study, we found that there was a potency of immune‐modulating effect on alpha‐lactalbumin (LA) and dextran (D) conjugate (LADC). There was no a significant difference between LA and LADC in terms of immune response in RAW 264.7 macrophage cell line. However, in this study, the immune‐enhancing effects of high molecular weight portion of LADC were shown DLA in RAW 264.7 was shown. LA and D were dry‐heated at 60¡É and 79% relative humidity for 1 and 15 days. SDS‐PAGE analysis was used to confirm the occurrence of the conjugated formation. 100 kDa membrane cut‐off was carried out to gain a high molecular weight portion of LADC. Immune‐enhancing effects were screened by nitric oxide (NO) production. TNF‐α, IL‐1β and IL‐6 cytokines were estimated in vitro. Data showed that the high molecular weight cutoff portion of LADC (LADCCO) showed dramatically increase of NO production. Also, LADCCO treated group presented high expression of immune‐related cytokines, TNF‐α, IL‐1β, and IL‐6, in RAW 264.7 macrophages. Therefore, our study suggests that high molecular weight cutoff portion of dextran glycated with alpha‐lactalbumin might be a new useful material for enhancing the immune responses.

The Maillard reaction is a chemical reaction between amino group and carbonyl group during food processing. In the case of milk, lactose reacts with the free amino acid side chain of milk protein.Infant formulas (IF) are milk‐based products and usually heat‐treated such as sterilization, spray‐dry to ensure microbiological safety and extend the shelf‐life period. As a consequence of thermal treatment, IF forms amadori products which then form advanced glycation end products (AGEs). IF may have more AGEs than breast milk. As a result, formula‐fed babies are being exposed to high levels of AGEs. In this study, we optimized the anti‐glycation effect of L‐carnitine, vitamin B6 and dl‐α‐tocopheryl acetate in IF model system using RSM.The model system was prepared by mixing sodium caseinate (3 mg/mL) and lactose (8.4 mg/mL) with and without antioxidants at 100°C for 30 min. The treatment conditions that were based on the central composite design with independent variables and the responses were monitored by fluorescence intensity and HMF content.The optimum levels of antioxidants for anti‐glycation in a model system, i.e.L‐carnitine, vitamin B6 and dl‐α‐tocopheryl acetate, were 8.05 μM, 12.37 μM, 18.4 μM for fluorescence intensity(63%), 1.6 μM, 18.4 μM, 18.4 μM for HMF(65%). Under these conditions, the experimental results were 90% for fluorescence intensity and 89% for HMF.

We have screened natural plants against formation of advanced glycation endproducts (AGEs), and selected yellow myrobalan (Terminalia chebula), Asiatic plantain (Plantago asiatica L.) and seaweed fulvescenes (Capsosiphon fulvescens). T. chebula, native to India and Southeast Asia, has been used for antidiabetic and cardioprotective effects. Hepatoprotective chebulic acid (CA) was isolated from T. chebula extract (TCE). The adhesion of THP‐1 monocytic cell adhesion to HUVEC with AGEs was reduced by the treatments of TCE or CA suggesting an effect for alleviating diabetic complications. In addition, the EtOAc‐soluble portion of TCE showed reduced the levels of blood glucose and serum lipids, and decreased the AGEs distribution in testis seminiferous tubules of rats. P. asiatica, is used as a folk medicine in Asian countries. From its extract, plantamajoside was isolated, and its glycation inhibitory activities were higher. In a randomized, double‐blind, placebo‐controlled parallel design, the human data showed reductions of plasma free fatty acid levels, oxidized low‐density lipoprotein levels and DNA damage in lymphocytes with high‐dose Asiatic plantain. Pheophorbide a (PhA) from C. fulvescens demonstrated significant activities of glycation inhibition, monocyte adhesive inhibition and down regulation of AGEs‐stimulated cytokines related to inflammation of the endothelium.Also, models of Maillard reaction products (MRPs) were applied to experimental batch‐type simulator models imitating human intestinal conditions, and affected the growth of gut commensal bacteria, particularly lactobacilli and bifidobacteria, whose levels increased significantly. There was a corresponding shift in the bacterial metabolites with increased level of lactate and decreased level of butyric acid with MRPs suggesting a health‐promoting effect in humans. In addition, MRPs showed immune‐modulating effects contribute to host immune defense through enhancing innate immune activity.

Plantago asiatica (PA) is widely distributed in Korea, China and Japan. It has traditionally been used as a folk remedy for various health benefits such as cough treatment and liver protection. The objective of this study was to demonstrate the reduction of excessive intracellular reactive oxygen species (ROS) through antioxidants and the anti‐glycation activity of PA. Dried roots of PA were boiled in ethanol for three hours, evaporated and lyophilized with a freeze‐dryer. The freeze‐dried powder of PAE was dissolved in distilled water and the solution was loaded onto a column packed with Diaion HP‐20 resin, which had been equilibrated with distilled water. The column was eluted with 2 L of 25% ethanol. Twenty‐five percent ethanol‐containing fraction (PAE‐D) was collected, and then concentrated using rotary vacuum evaporator. The concentrate was freeze‐dried. The total polyphenol content, flavonoid content, FRAP value, and DPPH‐ SC50 of PAED were 231.7 μg gallic acid equivalents/mg dry matter (DM), 211.7 μg quercetin equivalents/mg DM, 3.23 mmol FeSO4/mg DM and 282.0 μg DM/mL, respectively. The effects of the PAE‐D on AGE fluorescence were dose‐dependent, reaching 71% inhibition at 1 mg/mL of extract. In addition ROS scavenging assay were performed to investigate the possibility of PAE‐D in improving endothelial dysfunction‐induced diabetic complications. Treatment of PAE‐D significantly lowered the fluorescent formation due to advanced glycation reaction.Grant Funding Source : iPET, Korea