Anti-Gnawing, Thermo-Mechanical and Rheological Properties of Polyvinyl Chloride: Effect of Capsicum Oleoresin and Denatonium Benzoate

Anti-rodent polymer composites were prepared using non-toxic substances denatonium benzoate (DB) and capsicum oleroresin (CO) mixed with polyvinyl chloride (PVC) matrix. DB is mixed in zinc stearate (ZnSt) called DB/ZnSt, and CO, providing burning sensation, is impregnated in mesoporous silica named SiCO. There are three sets of sample: Blank, composites Set I and Set II. Set I consists of DB/ZnSt at concentration of 1.96 wt% and SiCO at concentration of 12.16 wt%, 14.47 wt%, 18.75 wt% and 23.53 wt%. Set II comprises SiCO at the same amount of Set I. The anti-rodent composites studied are anti-gnawing, surface morphology, thermo-mechanical and rheological properties. Anti-rodent testing is analyzed by one-way blocked analysis of variance (ANOVA) and compared with Tukey test with a 95% level of significance, presenting good anti-gnawing efficiency. The best rat-proof sample is II.4, consisting of SiCO 23.53 wt%, which presents percentage of weight loss from gnawing at 1.68% compared to weight loss of neat PVC at 59.74%. The addition of SiCO at concentration ranging from 12.16 to 23.53 wt% reduces tensile strength around 25–50%, elongation at break strength around 2–23%, shear storage modulus (G′) around 30%, shear loss modulus (G″) shear viscosity (η) and glass transition (Tg) around 43% compared to Blank. The increase in SiCO concentration slightly improves the thermal stability of PVC composites around 3%, but the addition of DB/ZnSt at 1.96 wt% slightly reduces those properties.

Denatonium Benzoate Exposure Promotes IgE-Mediated Mast Cell Degranulation and Allergy By Upregulating FcεRIα Expression

Background: Denatonium benzoate (DB), one of the bitterest compounds known to man, is currently added to a wide range of products and is also used for alcohol denaturation. Some reports demonstrated that asthmatic symptoms are associated with DB exposure but the possible links between DB and IgE-mediated allergy susceptibility have not been examined to date. We investigated the effects of DB on IgE-mediated mast cell degranulation in vitro and in the ovalbumin (OVA)-induced mouse model of allergy.Methods: DB treatments were given to RBL-2H3 IgE-sensitized rat mast cell/basophil cells and KU812 human basophilic cells together with OVA-induced allergic BALB/c mice. Allergic mediator release, Ca2+ influx and OVA-specific IgE anaphylactic shock symptoms were measured along with the cell-surface expression of the α-subunit of high-affinity IgE receptor FcεRI on mast cells.Results: DB increases β-hexosaminidase (β-hex) release and Ca2+ mobilization in IgE-mediated activated RBL-2H3 and KU812 cells, and enhanced the cell-surface expression of FcεRIα. DB also promoted the severity of OVA-induced anaphylactic and diarrheic symptoms which was accompanied by mucus thickness in jejunum and the levels of β-hex, histamine and OVA-specific IgE in allergy mice, as well as the levels of FcεRIα mRNA and the FcεRIα proteinin isolated mucosal mast cells. Conclusions: DB treatments can promote the IgE-mediated mast cell degranulation in vitro and OVA-induced allergic susceptibility in mice by upregulating mast-cell-surface FcεR1α expression, providing evidence for DB exposure in promoting allergy susceptibility.

Denatonium benzoate decreases the effect of histamine in vitro and in rats

Purpose: To evaluate the effect of denatonium benzoate (DB) in histamine-induced model of inflammation and the effect of the selective H1 receptor agonist (2-(2-Pyridyl) ethylamine) on rat gastric smooth muscle strips pretreated with DB.Methods: The anti-inflammatory effect of DB was evaluated in vivo on histamine-induced rat paw edema. In vitro studies on spontaneous muscle contraction were performed on smooth muscle strips isolated from rat gastric corpus.Results: The results showed a well-defined anti-inflammatory effect of DB (15 mg/kg) during the early stage of rat paw edema at the 15th (p < 0.001), 30th (p < 0.01) and 60th min (p < 0.001) compared to control. In vitro experiments indicated reduced spontaneous contractile activity of smooth muscle strips to H1 receptor agonist in the presence of DB (0.5 μM). The vascular effects of histamine are mediated by H1 receptors. Substances, which reduce the effect of histamine on the H1 receptors could influence the early stage of histamine-induced inflammation.Conclusion: The results show that the anti-inflammatory activity of DB probably is related to its antagonistic activity on histamine H1 receptors. The results would contribute to the search for new antiinflammatory drugs. Keywords: Denatonium benzoate, Inflammation, Histamine, Muscle contraction

Denatonium Benzoate-Induces Oxidative Stress in the Heart and Kidney of Chinese Fast Yellow Chickens by Regulating Apoptosis, Autophagy, Antioxidative Activities and Bitter Taste Receptor Gene Expressions

The sense of taste which tells us which prospective foods are nutritious, poisonous and harmful is essential for the life of the organisms. Denatonium benzoate (DB) is a bitter taste agonist known for its activation of bitter taste receptors in different cells. The aim of the current study was to investigate the mRNA expressions of bitter taste, downstream signaling effectors, apoptosis-, autophagy- and antioxidant-related genes and effector signaling pathways in the heart/kidney of chickens after DB dietary exposure. We randomly assigned 240, 1-day-old Chinese Fast Yellow chicks into four groups with five replicates of 12 chicks and studied them for 28 consecutive days. The dietary treatments consisted of basal diet and feed containing DB (5, 20 and 100 mg/kg). The results revealed that dietary DB impaired (p < 0.05) the growth performance of the chickens. Haemotoxylin and eosin staining and TUNEL assays confirmed that medium and high doses of DB damaged the epithelial cells of heart/kidney and induced apoptosis and autophagy. Remarkably, the results of RT-PCR and qRT-PCR indicated that different doses of DB gradually increased (p < 0.05) mRNA expressions of bitter taste, signaling effectors, apoptosis-, autophagy- and antioxidant- related genes on day 7 in a dose-response manner, while, these expressions were decreased (p < 0.05) subsequently by day-28 but exceptional higher (P < 0.05) expressions were observed in the high-dose DB groups of chickens. In conclusion, DB exerts adverse effects on the heart/kidney of chickens in a dose-response manner via damaging the epithelium of the heart/kidney by inducing apoptosis, autophagy associated with bitter taste and effector gene expressions. Correlation analyses for apoptosis/autophagy showed agonistic relationships. Our data provide a novel perspective for understanding the interaction of bitter taste, apoptosis, autophagy and antioxidative genes with bitter taste strong activators in the heart/kidney of chicken. These insights might help the feed industries and pave the way toward innovative directions in chicken husbandry.

Responsiveness Expressions of Bitter Taste Receptors Against Denatonium Benzoate and Genistein in the Heart, Spleen, Lung, Kidney, and Bursa Fabricius of Chinese Fast Yellow Chicken

The present study was conducted to investigate the responsiveness expressions of ggTas2Rs against denatonium benzoate (DB) and genistein (GEN) in several organs of the Chinese Fast Yellow Chicken. A total of 300 one-day-old chicks that weighed an average of 32 g were randomly allocated into five groups with five replicates for 56 consecutive days. The dietary treatments consisted of basal diet, denatonium benzoate (5 mg/kg, 20 mg/kg, and 100 mg/kg), and genistein 25 mg/kg. The results of qRT-PCR indicated significantly (p < 0.05) high-level expressions in the heart, spleen, and lungs in the starter and grower stages except for in bursa Fabricius. The responsiveness expressions of ggTas2Rs against DB 100 mg/kg and GEN 25 mg/kg were highly dose-dependent in the heart, spleen, lungs, and kidneys in the starter and grower stages, but dose-independent in the bursa Fabricius in the finisher stage. The ggTas2Rs were highly expressed in lungs and the spleen, but lower in the bursa Fabricius among the organs. However, the organ growth performance significantly (p < 0.05) increased in the groups administered DB 5 mg/kg and GEN 25 mg/kg; meanwhile, the DB 20 mg/kg and DB 100 mg/kg treatments significantly reduced the growth of all the organs, respectively. These findings indicate that responsiveness expressions are dose-dependent, and bitterness sensitivity consequently decreases in aged chickens. Therefore, these findings may improve the production of new feedstuffs for chickens according to their growing stages.