Effect of Polyphenols in Sea Buckthorn Berry on Chemical Mediator Release from Mast Cells

Sea buckthorn (Hippophae rhamnoides L.) is a deciduous shrub of the Elaeagnaceae family and is widely distributed in northern Eurasia. Sea buckthorn berry (SBB) has attracted attention for its use in many health foods, although its physiological function remains unknown. In this study, we investigated the inhibitory effect of SBB extract and its fractions on Type-I allergy using mast cell lines. Among these fractions, SBB fraction with the highest amount of antioxidant polyphenols significantly inhibited the release of chemical mediators such as histamine and leukotriene B4 (LTB4) from the stimulated mast cells. This fraction also inhibited the influx of calcium ions (Ca2+) and the phosphorylation of tyrosine residues in proteins, including spleen tyrosine kinase, which is associated with signal transduction during the release of chemical mediators. The active SBB fraction contained isorhamnetin as its major flavonol aglycon. Isorhamnetin inhibited histamine and LTB4 release from the stimulated cells and suppressed intracellular Ca2+ influx. These results indicate that isorhamnetin is the primary substance responsible for the antiallergic activity in SBB. In conclusion, SBB may alleviate Type-I allergy by inhibiting the release of chemical mediators from mast cells, and polyphenols may contribute to this effect.

Fermented Minor Grain Foods: Classification, Functional Components, and Probiotic Potential

Fermented minor grain (MG) foods often have unique nutritional value and functional characteristics, which are important for developing dietary culture worldwide. As a kind of special raw material in fermented food, minor grains have special functional components, such as trace elements, dietary fiber, and polyphenols. Fermented MG foods have excellent nutrients, phytochemicals, and bioactive compounds and are consumed as a rich source of probiotic microbes. Thus, the purpose of this review is to introduce the latest progress in research related to the fermentation products of MGs. Specific discussion is focused on the classification of fermented MG foods and their nutritional and health implications, including studies of microbial diversity, functional components, and probiotic potential. Furthermore, this review discusses how mixed fermentation of grain mixtures is a better method for developing new functional foods to increase the nutritional value of meals based on cereals and legumes in terms of dietary protein and micronutrients.

Anti-Inflammatory and Immunomodulatory Properties of Fermented Plant Foods

Fermented plant foods are gaining wide interest worldwide as healthy foods due to their unique sensory features and their health-promoting potentials, such as antiobesity, antidiabetic, antihypertensive, and anticarcinogenic activities. Many fermented foods are a rich source of nutrients, phytochemicals, bioactive compounds, and probiotic microbes. The excellent biological activities of these functional foods, such as anti-inflammatory and immunomodulatory functions, are widely attributable to their high antioxidant content and lactic acid-producing bacteria (LAB). LAB contribute to the maintenance of a healthy gut microbiota composition and improvement of local and systemic immunity. Besides, antioxidant compounds are involved in several functional properties of fermented plant products by neutralizing free radicals, regulating antioxidant enzyme activities, reducing oxidative stress, ameliorating inflammatory responses, and enhancing immune system performance. Therefore, these products may protect against chronic inflammatory diseases, which are known as the leading cause of mortality worldwide. Given that a large body of evidence supports the role of fermented plant foods in health promotion and disease prevention, we aim to discuss the potential anti-inflammatory and immunomodulatory properties of selected fermented plant foods, including berries, cabbage, and soybean products, and their effects on gut microbiota.

New isoflavone glucosides in yabumame (Amphicarpaea bracteata (L.) Fernald subsp. edgeworthii (Benth.) H.Ohashi var. japonica (Oliv.) H.Ohashi) and their effect on leukotriene B4 production in mast cells

Yabumame (Amphicarpaea bracteata (L.) Fernald subsp. edgeworthii (Benth.) H.Ohashi var. japonica (Oliv.) H.Ohashi) is a legume plant that the Ainu people eat as a traditional food, although the bioactive ingredients other than vitamins have not been studied. In this study, the structures of yabumame isoflavone glucosides were determined and their effect on leukotriene (LT) B₄, a chemical mediator of type I allergy, produced in mast cells, was investigated in vitro. Seven compounds were isolated from yabumame. Their structures were determined by spectroscopic and spectrometric analyses, which were genistein-7-O-β-D-glucoside (1), formononetin-7-O-(2″-O-β-D-glucosyl)-β-D-glucoside (2), formononetin-7-O-β-D-glucoside (3), biochanin A-7-O-(2″-O-β-D-glucosyl)-β-D-glucoside (4), formononetin-7-O-(6″-O-malonyl)-β-D-glucoside (5), biochanin A-7-O-(2″-O-β-D-glucosyl-6″-O-β-D-glucosyl)-β-D-glucoside (6), and biochanin A-7-O-(6″-O-malonyl)-β-D-glucoside (7). Compounds 2, 4, and 6 were determined as new compounds. Compound 3 showed statistically significant suppressive effect on LTB₄ production in mast cells, although the activity was not strong. On the other hand, biochanin A, an aglycone common to compounds 4, 6, and 7, strongly inhibited the LTB₄ production. The results suggest that some of yabumame isoflavone glucosides might contribute to mitigate type I allergy. Seven isoflavone glucosides including 3 new compounds were found in yabumame and their anti-allergic effect was evaluated.

A new method to evaluate anti-allergic effect of food component by measuring leukotriene B4 from a mouse mast cell line

Leukotrienes (LTs), chemical mediators produced by mast cells, play an important role in allergic symptoms such as food allergies and hay fever. We tried to construct an evaluation method for the anti-LTB₄ activity of chemical substances using a mast cell line, PB-3c. PB-3c pre-cultured with or without arachidonic acid (AA) was stimulated by calcium ionophore (A23187) for 20 min, and LTB₄ production by the cells was determined by HPLC with UV detection. LTB₄ was not detected when PB-3c was pre-cultured without AA. On the other hand, LTB₄ production by PB-3c pre-cultured with AA was detectable by HPLC, and the optimal conditions of PB-3c for LTB₄ detection were to utilize the cells pre-cultured with 50 µM AA for 48 h. MK-886 (5-lipoxygenase inhibitor) completely inhibited LTB₄ production, but AACOCF₃ (phospholipase A₂ inhibitor) slightly increased LTB₄ production, suggesting that LTB₄ was generated from exogenous free AA through 5-lipoxygenase pathway. We applied this technique to the evaluation of the anti-LTB₄ activity of food components. PB-3c pre-cultured with 50 µM AA for 48 h was stimulated with A23187 in the presence of 50 µM soybean isoflavones (daidzin, genistin, daidzein, and genistein), equol, quercetin, or kaempferol. Genistein, equol, quercetin, and kaempferol strongly inhibited LTB₄ production without cytotoxicity. These results suggest that a new assay system using PB-3c is convenient to evaluate LTB₄ inhibition activity by food components. This method could be utilized for elucidation of the mechanisms of LTB₄ release suppression by food components such as flavonoids and the structure-activity relationship.