Cow's milk αS1-casein is more sensitizing than goat's milk αS1-casein in a mouse model

The aim of this study was to compare the sensitization of α_S1-CN in cow and goat's milk in a mouse model. Fifty mice were divided into control group, adjuvant control group, cow's milk α_S1-CN sensitized group, goat's milk α_S1-CN sensitized group and cross sensitized group. Cow's and goat's milk α_S1-CN were used to establish a mouse sensitization model. The results showed that cow's milk α_S1-CN had higher allergenicity than goat's milk α_S1-CN, as can be seen in significantly increased s-IgE and Th2 cell-related inflammatory factors, the proportion of Th2, and the expression of Th2 cell-related transcription factors. Furthermore, the sensitization of cow's milk α_S1-CN damaged the intestinal barrier of mice, caused the leakage of LPS, activated the TLR4-NFκB pathway, and thus resulted in the increase of IFN-γ. In addition, mice allergic to cow's milk α_S1-CN were less sensitized to goat's milk α_S1-CN.

Mechanism of Reduction in Allergenicity and Altered Human Intestinal Microbiota of Digested β-Lactoglobulin Modified by Ultrasonic Pretreatment Combined with Glycation

The effects of ultrasound combined with glycation (UCG) on the allergenicity and human microbial community of β-Lg during in vitro digestion were studied by ELISA, cell experiments, and 16S rRNA high-throughput sequencing. UCG modification and subsequent digestion significantly reduced allergenicity. The decrease in the allergenicity of β-Lg depended not only on the low digestibility of glycated β-Lg, which led to the decrease of some peptides with complete immunogenicity, but also the masking effect of glycation on allergen epitopes of β-Lg. Meanwhile, UCG modification and subsequent digestion could alter the structures of intestinal microbiota and the community abundance at phylum, family, and genus levels, such as Bacteroidota, Fusobacteriota, Enterobacteriaceae, Bacteroidaceae, Ruminococcaceae, Bacteroides, and Faecalibacterium. These results show that simulated in vitro digestion of modified β-Lg reduces allergenicity and alters human intestinal microbiota, which could provide a theoretical basis for studying the relationship between intestinal dysbiosis and cow's milk allergy.

Bovine β-Lactoglobulin Covalent Modification by Flavonoids: Effect on the Allergenicity and Human Intestinal Microbiota

The present study aims to investigate the structure of covalent conjugates of bovine β-lactoglobulin (BLG) and flavonoids (luteolin, myricetin, and hyperoside), and their effect on the allergenicity and human intestinal microbiota. Covalent modification of amino acids in BLG by flavonoids was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and o-phthaldialdehyde assay. The secondary and conformational structures of BLG were changed by the covalent modification, which were determined by the circular dichroism, Fourier transform infrared spectroscopy, fluorescence spectroscopy, and UV spectroscopy. The enzyme-linked immunosorbent assay (ELISA) and cell experiments indicated that BLG covalent conjugates could reduce IgE/IgG binding capacities and suppress the allergy reactivity of RBL-2H3 cells, suggesting that the covalent modification modulated the balance of T cells. Meanwhile, covalent modification of BLG with these flavonoids can alter the diversity of human intestinal microbiota and the community abundance at phylum, family, and genus levels. The results revealed that covalent modification of BLG with flavonoids alters human intestinal microbiota, might result in the reduction of allergenicity, which could provide information for confirming the relationship between food allergy and the intestinal microbial ecosystem.

Milk and Meat Allergens from Bos taurus β-Lactoglobulin, α-Casein, and Bovine Serum Albumin: An In-Vivo Study of the Immune Response in Mice

The mechanism of food allergy may vary. This study aimed to compare the effects of milk, yogurt, or beef meat supplementation on humoral and cellular immune responses in a mice model. Mice were divided into four groups: The "Milk group" was sensitized with a β-lactoglobulin (β-lg)/α-casein (α-CN) mixture and supplemented cow milk; the "Yogurt group" was sensitized with β-lg/α-CN and supplemented yogurt; the "Beef group" was immunized with bovine serum albumin (BSA) and supplemented beef meat; and the "PBS group" received PBS in all procedures. ELISA was used to measure humoral response, including: Total IgE, specific IgG, and IgA. Cellular response was determined by phenotyping lymphocyte from lymphoid tissue and measuring the Th1/Th2 cytokine concentration with flow cytometry. The qPCR method was used for quantification of the fecal microbiota. The results obtained revealed a lower IgE level for the Yogurt group than for the Milk one. In the Yogurt group, the contribution of regulatory T cells to MLN and PP was higher compared to the other groups. We confirmed that diet supplementation with yogurt modulates the immune response to the prime allergen, and changes the activity of serum antibodies to milk proteins and BSA. Based on a specific antibodies level, we cannot exclude the possibility of CMA mice reaction against BSA.

Effect of carvacrol essential oils on immune response and inflammation-related genes expression in broilers challenged by lipopolysaccharide

This experiment was conducted to study the effects of orally administered carvacrol essential oils on immune response and inflammation-related genes expression in broilers challenged by lipopolysaccharide (LPS). Eighty 28-day-old (1.28 ± 0.15 kg) ROSS 308 broilers were assigned to a 2 × 2 factorial arrangement of treatments (20 pens of 1 chick/trt). Factors were carvacrol essential oil (orally administered or non-orally administered) and LPS (challenged or non-challenged). Individually housed broilers were randomly assigned (n = 20 broilers per treatment: 10 males and 10 females) to four treatments: (1) basic diet (CTR), (2) basic diet + carvacrol (CAR), (3) basic diet + LPS-challenge (LPS), (4) basic diet + carvacrol + LPS-challenge (CAR+LPS). All were fed with the same diet. The experimental period was for 15 d, after which injecting LPS significantly up-regulated the gene expression levels of TNF-α (P < 0.05), IL-1β (P < 0.05), IL-6 (P < 0.05), IL-8 (P < 0.05), TLR2 (P < 0.05), TLR4 (P < 0.05), NF-κB p65 (P < 0.05), AVBD-9 (P < 0.05), and SIgA(P < 0.05) compared with the CTR group; the broilers were challenged by LPS after oral administration of carvacrol, they had significant lower on the gene expression levels of TNF-α (P < 0.05), IL-1β (P < 0.05), IL-6 (P < 0.05), TLR4 (P < 0.05), NF-κB p65 (P < 0.05), and AVBD-9 (P < 0.05) than the LPS group. In conclusion, the broilers orally administrated carvacrol essential oils inhibited the secretion of inflammatory cytokines caused by LPS, affected the pathway of TLRs/NF-κB, and showed an anti-inflammatory function.

Skullcap (Scutellaria Baicalensis) Hexane Fraction Inhibits the Permeation of Ovalbumin and Regulates Th1/2 Immune Responses

Skullcap (Scutellaria baicalensis) is well known for its anti-inflammatory and anti-allergic effects. In our previous study, we found that skullcap could inhibit allergen permeation and regulate Th1/2 immune balance. To reveal the key fractions and components of skullcap, we fractionated skullcap extract into five fractions: hexane, chloroform, ethyl acetate, butanol, and water fraction. Among these fractions, the hexane fraction significantly suppressed the production of Th2-mediated cytokines (Interleukin (IL)-4, 5, 10 and 13) and increased Th1-mediated cytokines (Interferon (IFN)-γ and IL-12). Furthermore, the hexane fraction inhibited the permeation of ovalbumin (OVA), used as an allergen, across the intestinal epithelial cell monolayer. To confirm the active compounds in the hexane fraction, fatty acids were analyzed. Linoleic acid (LA, C18:2 (>59.7%)) was identified as the most important fatty acid in the skullcap hexane fraction. LA significantly suppressed IL-4 production and increased IFN-γ secretion, as well as inhibiting OVA permeation. Thus, LA significantly diminished the permeation of allergen by enhancing intestinal barrier function and regulated allergic responses to maintain Th1/Th2 immune balance.

Baicalein induces CD4(+)Foxp3(+) T cells and enhances intestinal barrier function in a mouse model of food allergy

The incidence of food allergy, which is triggered by allergen permeation of the gastrointestinal tract followed by a T-helper (Th) 2-mediated immune response, has been increasing annually worldwide. We examined the effects of baicalein (5,6,7-trihydroxyflavone), a flavonoid from Scutellaria baicalensis used in oriental herbal medicine, on regulatory T (Treg) cell induction and intestinal barrier function through the regulation of tight junctions in a mouse model of food allergy. An allergic response was induced by oral challenge with ovalbumin, and the incidence of allergic symptoms and T cell-related activity in the mesenteric lymph nodes were analyzed with and without the presence of baicalein. Our results demonstrated that the administration of baicalein ameliorated the symptoms of food allergy and attenuated serum IgE and effector T cells. However, Treg-related factors were up-regulated by baicalein. Furthermore, baicalein was shown to enhance intestinal barrier function through the regulation of tight junctions. We also found that baicalein treatment induced the differentiation of Treg cells via aryl hydrocarbon receptors (AhRs). Thus, the action of baicalein as an agonist of AhR can induce Treg differentiation and enhance barrier function, suggesting that baicalein might serve as an effective immune regulator derived from foods for the treatment of food allergy.

A Mainstay of Functional Food Science in Japan—History, Present Status, and Future Outlook

The development of food science in the near future probably depends on the advance in functional food science, the concept of which was proposed first in Japan nearly 15 years ago. The new science has been internationally distributed and accepted as conceptually being beyond nutrition. In Japan, however, it traced a unique path of progress in the form of a product-driven rather than concept-driven science. Actually, a number of substances and products with potential for disease risk reduction rather than simply for health maintenance have been investigated for their body-modulating functions. Some of them have been applied in practice to the industrialization of functional foods in terms of "foods for specified health uses" legally defined by new legislation. A variety of sophisticated methods have been introduced as well, including the so-called "XYZ" evaluation system, database construction for assessment of the function, and even the DNA microarray technique. The Ministry of Agriculture, Forestry, and Fisheries (MAFF) and the Ministry of Health and Welfare (MHW) also commenced their scientific as well as political activity, with its spread to industries which almost simultaneously began to vigorously investigate functional food products for enlargement of the food market. With all of this as a background, the Japan Liaison of the International Union of Food Science and Technology (IUFoST) hold a function food science symposium on behalf of related scientific bodies including the Japan Section of the International Life Science Institute (ILSI). This paper is an overview compiled from 12 presentations made in the symposium, with the aim of internationally publicizing the activity of functional food science in Japan.

Preventive effects of skullcap (Scutellaria baicalensis) extract in a mouse model of food allergy

ETHNOPHARMACOLOGICAL RELEVANCE

Food allergy, which accompanies acute symptoms such as pruritus, vomiting, diarrhea, and lethal anaphylactic shock is an increasing clinical problem. Skullcap (Scutellaria baicalensis Georgi) has been widely used as a traditional herbal medicine to treat inflammation, cancer, and allergy, but its effects in treating food allergy are not yet known.

MATERIALS AND METHODS

To examine the effect of skullcap on food allergy, female BALB/c mice were sensitized with 20 μg OVA and 2mg alum by intraperitoneal injection on day 0. From day 17, mice were orally challenged with OVA (50 mg) in saline every 3 days, for a total of six times. To investigate the preventive effect, skullcap (25 mg/kg) was orally administered every day from day 17 to 34.

RESULTS

Food allergy symptoms were evaluated by the criteria for diarrhea, anaphylactic response, and rectal temperature. Severe symptoms of food allergy were observed in the sham group (diarrhea, 3 points; anaphylactic response, 2.6 points; rectal temperature, -8.36 °C. In contrast, the skullcap treatment group had a significantly suppressed OVA-induced anaphylactic response (1.3 points) and rectal temperature (-4.76°C). Moreover, both OVA-specific IgE, Th17 cytokine (IL-17), and Th2-related cytokines (IL-4, IL-5, IL-10, and IL-13), which increased with food allergy, were significantly inhibited by skullcap treatment.

CONCLUSION

We demonstrate that the administration of skullcap attenuates OVA-induced food allergy symptoms through regulating systemic immune responses of Th cells. These results indicate that skullcap may be a potential candidate as a preventive agent for food allergy.

Inhibitory effect of skullcap (Scutellaria baicalensis) extract on ovalbumin permeation in vitro and in vivo

Scutellaria baicalensis Georgi (skullcap) has been widely used as a dietary ingredient. The purpose of this study was to reveal novel function of skullcap and its mechanism on allergen permeation in intestinal epithelial cells. Intestinal epithelial Caco-2 cell monolayers were used to evaluate the inhibitory effect of skullcap on ovalbumin (OVA) permeation by measuring transepithelial electrical resistance (TEER) and the quantity of permeated OVA. TEER increased and the OVA flux decreased in a dose-dependent manner through up-regulating tight junction-related proteins in cells incubated with increasing concentrations of skullcap extract. In the in vivo study, the amounts of OVA from orally ingested albumen reduced on administration of the skullcap extract. We also revealed for the first time that the active component of skullcap extract for inhibition of OVA permeation was baicalein. These findings demonstrated that skullcap extract might attenuate a food allergic response by inhibiting allergen permeation in vitro and in vivo.

The casein peptide Asn-Pro-Trp-Asp-Gln enforces the intestinal tight junction partly by increasing occludin expression in Caco-2 cells

We have demonstrated previously that Asn-Pro-Trp-Asp-Gln (NPWDQ, amino acids 107–111 of αs2-casein) inhibited allergen permeation, such as that demonstrated by ovalbumin, using Caco-2 cells as an in vitro human intestinal epithelial model and in mouse jejunal and ileal loops ex vivo. In the present study, the mechanism underlying this inhibitory activity was examined in Caco-2 cells. Transepithelial resistance value increased in response to the addition of increasing NPWDQ concentrations (10− 6–10− 4 m), which suggests that this peptide enhanced epithelial barrier function. Next, changes in mRNA expression by the addition of NPWDQ (10− 6 m) were analysed in Caco-2 cells using the microarray method. NPWDQ up-regulated the expression of the occludin gene in cells, but the level of the genes of the claudin family and zonula occludens-1 (ZO-1) was unchanged. Increased protein expression of occludin, but not of claudin-1 or of ZO-1, was also observed. Therefore, it is suggested that NPWDQ up-regulated the expression of occludin in particular and enforced the tight junction barrier. These data imply that a food-derived peptide can fine-tune the epithelial barrier.

Identification of a peptide in enzymatic hydrolyzate of cheese that inhibits ovalbumin permeation in Caco-2 cells

Because the first step in the triggering of food allergy is the permeation of the allergen through the intestine, enhancement of the intestinal barrier function is thought to be effective for preventing food allergy. In this study, a peptide that inhibits ovalbumin (OVA) permeation in an in vitro Caco-2 cell model was isolated from enzymatic hydrolyzate of cheese (EHC). Amino acid sequence analysis identified the active peptide as GPIVLNPWDQ, a sequence identical to amino acids 102-111 of alphas2-casein. The decapeptide significantly inhibited OVA permeation at a concentration of 10(-6) M. In addition, it was found that a pentapeptide half, NPWDQ, is essential for the inhibitory activity because NPWDQ but not GPIVL had nearly the same inhibitory activity as GPIVLNPWDQ. The possibility exists that EHC and/or peptides possessing the NPWDQ sequence can be practically applied to the prevention of food allergy.

Polyphenols from some foodstuffs as inhibitors of ovalbumin permeation through caco-2 cell monolayers

Some spices showed high inhibitory activity against ovalbumin permeation through Caco-2 cell monolayers. Pimentol from allspice, rosmarinic acid and luteolin-7-O-beta-glucuronide from thyme, quercetin-3-O-beta-glucuronide from coriander and rutin from tarragon were identified as the active principles. A structure-activity relationship study among the active isolates and their related compounds indicated that the presence of a catechol structure played an important role in the inhibitory activity of each compound.

Isolation and structural elucidation of a peptide derived from Edam cheese that inhibits beta-lactoglobulin transport

A peptide that inhibits beta-lactoglobulin absorption in an in vitro Caco-2 cell model was isolated from Edam cheese. By 1H-NMR and N-terminal amino acid analyses, the active compound was identified as Asp-Lys-Ile-His-Pro-Phe. The sequence of the hexapeptide is the same as the amino acid sequence of residues 47-52 of beta-casein. The hexapeptide shows remarkable inhibition of beta-lactoglobulin transport at a concentration of 10(-7)M. The possibility exists that this peptide can be applied practically to the prevention of milk-sensitive allergy.

An active compound against allergen absorption in hypoallergenic wheat flour produced by enzymatic modification

Hypoallergenic wheat flour produced by modification with cellulase and actinase showed inhibitory activity against ovalbumin permeation in an in vitro model by using the Caco-2 cell monolayer. The activity was found in the cellulase preparation used for producing the flour. An active compound was isolated by HPLC and identified as Trp-Ser-Asn-Ser-Gly-Asn-Phe-Val-Gly-Gly-Lys by 1H-NMR data and Edman degradation. The undecapeptide, some oligopeptides with the N-terminal sequences and Trp ethyl ester showed activity at 10(-7) M, acetyl Trp being active at 10(-2) M. These data suggest that the Trp residue without a free carboxyl group would be required for the inhibitory activity of ovalbumin absorption through the intestinal tract.