Ishizuchi dark tea suppresses IgE-mediated degranulation of RBL-2H3 cells and nasal rubbing behavior of pollinosis in mice

Effect of Hita Tenryo Water™, a natural mineral water, on allergic symptoms induced by cedar in mice

The number of patients with allergies to pollen and food is increasing worldwide. In Japan, the prevalence of cedar pollinosis, a type I allergy, is nearly 30% and accounts of hay fever are rising. A potential natural remedy for these allergic diseases may be Hita Tenryo Water™ (referred to simply as Hita Tenryo water), water that is pumped from deep underground in the Hita region of Oita, Japan, which has been the subject of various research reports. Here, we investigated the potential of using Hita Tenryo water to suppress the onset of cedar pollinosis in a mouse model and explored the immunological mechanism of the suppression. Test model mice were given Hita Tenryo water ad libitum to drink and received intraperitoneal administration of (i) tap water (Hw1), (ii) 25% Hita Tenryo water (Hw2) or (iii) 100% Hita Tenryo (Hw3). There were no significant differences in body weight change, feed intake, or water intake among the groups during the experimental period. We examined nose rubbing and sneezing as allergic symptoms. The frequency of rubbing and sneezing tended to decrease in the Hw1 and Hw2 group, and significantly decreased in the Hw3 group compared to control. Total IgE levels in serum were also significantly reduced in Hita Tenryo water intraperitoneal administration groups. In vitro examination of the rate of release of β-hexosaminidase from BL-2H3 cells showed that there were no significantly differences between Hita Tenryo water-treated and control cells. In addition, measurement of Th2-related cytokine levels in concanavalin A-stimulated peripheral blood mononuclear cells revealed a significant decrease in IL-4, IL-6, and IL-10 levels in medium (p < 0.01). In contrast, production of IFN-γ significantly increased (p < 0.01). These results indicate that Hita Tenryo water may alleviate and/or suppress allergic symptoms.

Catechins: Protective mechanism of antioxidant stress in atherosclerosis

Tea has long been valued for its health benefits, especially its potential to prevent and treat atherosclerosis (AS). Abnormal lipid metabolism and oxidative stress are major factors that contribute to the development of AS. Tea, which originated in China, is believed to help prevent AS. Research has shown that tea is rich in catechins, which is considered a potential source of natural antioxidants. Catechins are the most abundant antioxidants in green tea, and are considered to be the main compound responsible for tea's antioxidant activity. The antioxidant properties of catechins are largely dependent on the structure of molecules, and the number and location of hydroxyl groups or their substituents. As an exogenous antioxidant, catechins can effectively eliminate lipid peroxidation products. They can also play an antioxidant role indirectly by activating the endogenous antioxidant system by regulating enzyme activity and signaling pathways. In this review, we summarized the preventive effect of catechin in AS, and emphasized that improving the antioxidant effect and lipid metabolism disorders of catechins is the key to managing AS.

Dietary Theabrownin Supplementation Improves Production Performance and Egg Quality by Promoting Intestinal Health and Antioxidant Capacity in Laying Hens

Theabrownin, an activated and ample pigment in Pu-erh tea, is known to exert antiobesity and antihyperlipidemic effects in humans, mice, and rats. In this study, we aimed to explore the effects of theabrownin (TB) dietary supplementation on production performance, egg quality, intestinal health, and antioxidant capacities in laying hens. In total, 160 Lohmann laying hens (25 weeks old) were randomly split into four groups (each group 40 hens), namely the CONT (control, basal diet + 0 mg/kg TB), TB1 (basal diet + 100 mg/kg TB), TB2 (basal diet + 200 mg/kg TB), and TB4 (basal diet + 400 mg/kg TB) groups, respectively. These were supplemented with TB for 12 weeks. The results showed that the TB1 group exhibited a significantly higher laying rate during 9 to 12 weeks and higher egg weight and feed conversion efficiency (lower FCR) during 5 to 8 weeks and in the overall period (1 to 12 weeks) than the CONT group (p < 0.05). Compared with the CONT group, the eggs from the TB4 group had higher albumen height and Haugh unit than those from the other treatment groups after the 8th and 12th week; notably, the same was also observed in the TB1 and TB2 groups but only after the 12th week (p < 0.05). The albumen quality (albumen height and Haugh unit) after 3 weeks of storage was significantly higher in the TB1, TB2 and TB4 groups than in the CONT group (p < 0.05). Furthermore, TB supplementation lowered the serum levels of total cholesterol and total triglyceride (p < 0.05). Expression analysis revealed that TB2 and TB4 groups had reduced expression of tumor necrosis factor-α (p < 0.05), while TB1, TB2, and TB4 had significantly decreased expression of interleukin-1β and IL-6 (p < 0.05). Conversely, zonula occludens-1, claudin-1, and mucin-2 were upregulated in the TB2 and TB4 groups (p < 0.05). Meanwhile, dietary TB supplementation ameliorated the antioxidant status of the ovary and the magnum, showing a significant reduction in malondialdehyde and 8-hydroxydeoxyguanosine levels in the magnum, the upregulation of glutathione in the ovary, and superoxide dismutase and catalase in the magnum (p < 0.05). Overall, dietary supplementation with TB (>100 mg/kg) improved production performance and egg storage quality by improving the intestinal health and antioxidant capacities of the reproductive system in laying hens.

Controlling the microbial composition during the fermentation of Ishizuchi-kurocha

Ishizuchi-kurocha is a popular postfermented tea in Japan. It is performed by domestic and natural fermentation relied on microorganisms derived from tea leaves or the environment of the manufacturing. Ishizuchi-kurocha undergoes aerobic fermentation of fungi first, then second fermented by anaerobic fermentation of lactic acid bacteria during natural fermentation processing. Aspergillus niger that produces mycotoxin is included in natural fermentation. This research aimed to build a novel fermentation method of Ishizuchi-kurocha by adding industrial koji fungi products and laboratory-cultivated Lactobacillus plantarum (Lactiplantibacillus plantarum) artificially. Thus, safety and quality of tea products could be controlled simply. We found artificial fermentation of Ishizuchi-kurocha could get high lactic acid production within 8 days. Final products only consisted of genus Aspergillus and genus Lactobacillus, while harmful Aspergillus niger was not found. However, artificial fermentation methods also decreased the content of polyphenols when compared with commercial tea.

Potential hypoglycemic metabolites in dark tea fermented by Eurotium cristatum based on UPLC-QTOF-MS/MS combining global metabolomic and spectrum-effect relationship analyses

The preventive and therapeutic effects of dark tea fermented by Eurotium cristatum (DTE) in glucose metabolism have been demonstrated. However, few studies have investigated comprehensive changes in the chemical composition and activity in DTE before and after fermentation. In this study, the metabolic profiling of raw samples and fermented samples was determined by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS). Furthermore, a systematic analytical strategy combining global metabolomics and the spectrum-effect relationship based on α-glucosidase inhibition was employed for screening discriminant metabolites. As a result, 15 discriminant metabolites were identified in DTE samples. Among them, 10 metabolites (4 fatty acids, 1 dyphylline derivative, 3 lysophosphatidylcholines, and 2 triterpenes) increased in relative contents and the contents of the other 5 polyphenol metabolites decreased after fermentation. These metabolites were critical constituents possibly associated with DTE's hypoglycemic activity, which also might be suitable as quality evaluation indicators. This study provided a worthy insight into the exploration of representative active constituents or quality indicators of DTE.

Anti-type I allergic effects of Jing-Fang powder extracts via PI3K/Akt pathway in vitro and in vivo

Jing-Fang powder (Schizonepeta tenuifolia Briq. and Saposhnikovia divaricata (Turcz.) Schischk.) was used to treat chronic bronchitis, asthma and chronic urticaria. Based on the preliminary results of screening research on the antiallergic effective parts of Jing-Fang powder, its ethyl acetate extract fractions (JFEE) and isolate D (JFEE-D) showed the best anti-allergic effect. RBL-2H3 cell activation degranulation model and mice passive cutaneous anaphylaxis (PCA) reaction model were used to investigate the effects and mechanisms of JFEE and JFEE-D on IgE-mediated type I allergic reactions. LC-MS was utilized to determine the composition of JFEE and JFEE-D. We found that JFEE and JFEE-D significantly reduced β-HEX, histamine, IL-4, IL-6 levels in cell supernatants, and improved the degree and morphology of cell degranulation. JFEE and JFEE-D significantly inhibited the increase of ear vascular permeability and abnormal increase of serum IgE, TNF-α, IL-6 levels. JFEE and JFEE-D inhibited mRNA expression of PI3K and Akt and down-regulated protein expression of PI3K, Akt, p-Akt, and PLCγ1 in sensitized RBL-2H3 cells. The combined use of JFEE and JFEE-D with pathway inhibitor Wortmannin revealed synergistic down-regulation of PI3K, Akt, and p-Akt protein expression. The combined use of pathway agonist IGF-1, JFEE and JFEE-D down-regulated increase of p-Akt/Akt protein expression. Moreover, JFEE and JFEE-D significantly inhibited protein expression of PI3K, p-Akt and PLCγ1 in PCA model mice. These results show that JFEE and JFEE-D inhibit type I allergic reactions by inhibiting PI3K/Akt signaling pathway.

Qing brick tea (QBT) aqueous extract protects monosodium glutamate-induced obese mice against metabolic syndrome and involves up-regulation Transcription Factor Nuclear Factor-Erythroid 2-Related Factor 2 (Nrf2) antioxidant pathway

BACKGROUND

Qing brick tea (QBT), traditional and popular beverage for Chinese people, is an important post-fermentation dark tea. Our present study was performed to investigate the ameliorative effects of QBT aqueous extract on metabolic syndrome (Mets) in monosodium glutamate-induced obese mice and the potential mechanisms.

METHOD

Monosodium glutamate-induced obese mice were used to evaluate the anti-Mets effects of QBT. Content levels of malonaldehyde (MDA), reactive oxygen species (ROS) and protein carbonylation, antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR) in the skeletal muscle were assessed by commercial kits, respectively. Western blot and Q-PCR were used to detect the expressions of Transcription Factor Nuclear Factor-Erythroid 2-Related Factor 2 (Nrf2) signaling pathway and downstream antioxidant factors. In addition, activity of AKT signaling and expression of glucose transporter type 4 (GLUT4) in the skeletal muscle were investigated by western blot.

RESULT

QBT treatment limited gain of body weight, waistline and LEE index, improved insulin resistance and glucose intolerance, reduced lipid level in MSG mice. Content levels of MDA, ROS and protein carbonylation in skeletal muscle of QBT group were significantly improved compared to those of MSG mice. The antioxidant enzyme activities of SOD, GPx, CAT, and GR were increased in skeletal muscle of MSG mice intervened with QBT. After 20-week QBT treatment, Nrf2 signaling pathway and downstream antioxidant factors were both increased in the skeletal muscle. In addition, QBT treatment improved insulin signaling by preferentially augmenting AKT signaling, as well as increased the protein expression of GLUT4 in the skeletal muscle.

CONCLUSION

Our results showed that QBT intake was effective in protecting monosodium glutamate-induced obese mice against metabolic syndrome and involved in the Nrf2 signaling pathway in the skeletal muscle.

Multiple responses optimization of instant dark tea production by submerged fermentation using response surface methodology

In this study, submerged fermentation mode for preparing instant dark tea production was developed through utilizing industrial low grade green tea as raw material and Aspergillus niger as fermentation microbe starter. The fermentation parameters (inoculum size, liquid-solid ratio and rotation speed) were optimized by using Box-Behnken design and response surface methodology (RSM) with desirability function, the theabrownins content, redness and turbidity value as responses. The optimal conditions were set as follow: inoculum size of 5.3% (v/v), liquid-solid ratio of 27.78 mL/g, and rotation speed of 182 r/min. The optimized conditions model showed a good correlation between the predicted and experimental values. Further, the optimum product of instant dark was achieved in a 3-L laboratory fermenter, and the main parameters of product were theabrownins content of 140.92 g/kg and redness value of 40.78 and turbidity of 90.98 NTU. Sensory evaluation showed that the instant dark tea infusion approached mellow mouthfeel, an aroma of mint and a good overall acceptance.

Inhibitory effect of Japanese black vinegar on IgE-mediated degranulation of RBL-2H3 cells and a murine model of Japanese cedar pollinosis

Japanese black vinegar (JBV) is a traditional vinegar manufactured with steamed unpolished rice. After screening, beneficial effects of JBV on IgE-mediated allergic responses were found. In this study, acetic acid-free JBV was used to evaluate its antiallergic effects. JBV suppressed degranulation of rat basophilic leukemia RBL-2H3 cells in a dose-dependent manner without cytotoxicity. The inhibitory effect of JBV on the degranulation seemed to be caused by the bioactive ingredients other than proteins, because the activity was not affected by heat treatment or protease digestion. JBV inhibited the elevation in the intracellular Ca²⁺ concentration induced by antigen. Immunoblot analysis revealed that JBV suppresses degranulation of RBL-2H3 cells by downregulated phosphorylation of PI3K, Akt, and PLCγ1. In addition, oral administration of JBV significantly suppressed passive cutaneous anaphylaxis reaction in mice and an allergic symptom in Cry j1-induced pollinosis model mice. Thus, JBV has a potential as a health-promoting food with the antiallergy effect.

Suppressive effect of ethanol extract from mango (Mangifera indica L.) peel on IgE production in vitro and in vivo

Immunoglobulin E (IgE) is involved in the onset of allergic reaction, and the suppression of IgE production leads to alleviation of allergic symptoms. We found that mango peel ethanol extract (MPE) significantly suppresses IgE production by human myeloma cell line U266 cells, suggesting that MPE has an anti-allergic effect by inhibiting the production of IgE. Although mangiferin is contained in mango, which suppresses IgE production by U266 cells, it was not contained in MPE. We investigated the suppressive effect of MPE in 2,4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis model mice. The elevation of serum IgE level was significantly suppressed by oral administration of MPE. Intake of MPE also suppressed the expression level of IL-4 in the DNFB-challenged ears, suggesting that MPE suppresses the IL-4-mediated maturation into IgE-producing cells. Our findings indicate that MPE has a potential to alleviate the increase in serum IgE level that is feature of type I allergy.

High-theabrownins instant dark tea product by Aspergillus niger via submerged fermentation: α-glucosidase and pancreatic lipase inhibition and antioxidant activity

BACKGROUND

Theabrownins (TB) are bioactive components that are usually extracted from Chinese dark tea, in which they are present at low concentrations. The present study aimed to produce an instant dark tea high in theabrownins via submerged fermentation by the fungus Aspergillus niger. Three fermentation parameters that affect theabrownins content (i.e. inoculum size, liquid-solid ratio and rotation speed) were optimized using response surface methodology.

RESULT

Optimum fermentation conditions were modeled to be an inoculum of 5.40% (v/v), a liquid-solid ratio of 27.45 mL g^-1 and a rotation speed of 184 rpm and were predicted to yield 292.99 g kg^-1 TB. Under these experimentally conditions, the TB content of the instant dark tea was 291.93 g kg^-1 . The antioxidant capacity and α-glucosidase and pancreatic lipase inhibitory activities of the high-TB instant black tea were higher than four other typical instant dark tea products.

CONCLUSION

The results of the present study show that careful management of culture conditions can produce a dark tea high in theabrownins. Furthermore, high-theabrownins instant dark tea could serve as a source of bioactive products and be used in functional foods as an ingredient imparting antioxidant properties and the ability to inhibit pancreatic lipase and α-glucosidase. © 2017 Society of Chemical Industry.

In vitro α-glucosidase inhibitory activity of isolated fractions from water extract of Qingzhuan dark tea

BACKGROUND

Natural products have being used as potential inhibitors against carbohydrate-hydrolyzing enzymes to treat diabetes mellitus. Chinese dark tea has various interesting bioactivities. In this study, the active compounds from Qingzhuan dark tea were separated and their anti-diabetic activity was examined using an in vitro enzymatic model.

METHODS

The chloroform, ethyl acetate, n-butanol, sediment and residual aqua fractions of a Chinese dark tea (Qingzhuan tea) were prepared by successively isolating the water extract with different solvents and their in vitro inhibitory activities against α-glucosidase were assessed. The fraction with the highest inhibitory activity was further characterized to obtain the main active components of Qingzhuan tea.

RESULTS

The ethyl acetate fraction had the greatest inhibitory effect on α-glucosidase, followed by n-butanol, sediment and residual aqua fractions (with the IC₅₀ values of 0.26 mg/mL, 2.94 mg/mL, 3.02 mg/mL, and 5.24 mg/mL, respectively), mainly due to the high content of polyphenols. Among the eight subfractions (QEF1-8) isolated from the ethyl acetate fraction, QEF8 fraction showed the highest α-glucosidase inhibitory potential in a competitive inhibitory manner (the K _i value of 77.10 μg/mL). HPLC-MS analysis revealed that (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) were the predominant active components in QEF8.

CONCLUSION

These results indicated that Qingzhuan tea extracts exerted potent inhibitory effects against α-glucosidase, EGCG and ECG were likely responsible for the inhibitory activity in Qingzhuan tea. Qingzhuan tea may be recommended as an oral antidiabetic diet.

Inhibitory effects of enzyme-treated dried sardine extract on IgE-mediated degranulation of RBL-2H3 cells and a murine model of Japanese cedar pollinosis

Protease-digested small dried sardine extract relieved allergic symptoms in mice through inhibiting microtubule dynamics.