Selenium-Enriched Soy Protein Has Antioxidant Potential via Modulation of the NRF2-HO1 Signaling Pathway.

Selenium (Se)-enriched proteins are an important dietary source of Se for humans; however, only a few Se-enriched proteins have been identified. In the present study, we tested for potential antioxidant activity by Se-enriched soy protein, both in vitro and in vivo. Se-enriched soy protein isolate (S-SPI) was shown to have a higher free radical scavenging ability compared to ordinary soy protein isolate (O-SPI). Furthermore, Caco-2 cell viability was improved by S-SPI at low doses, whereas O-SPI did not. In addition, S-SPI was shown to inhibit oxidative stress via modulation of the NRF2-HO1 signaling pathway, upregulating the expression of downstream antioxidant enzymes (GPx, SOD). To further study the antioxidant capacity of S-SPI, BALB/c female mice were given oral gavages with 0.8 mL of S-SPI or O-SPI (5 g/kg/d, 20 g/kg/d and 40 g/kg/d) or saline as control. Hepatic GPx and SOD activity increased with increasing S-SPI dosage, but not with O-SPI. Taken together, our results suggest that Se-enriched soy protein has a high antioxidant ability and may be used as a dietary supplement for people with oxidative dam-age-mediated diseases.

Potential allergenicity assessment after bovine apo-α-lactalbumin binding to calcium ion.

Bovine α-lactalbumin (α-LA) is recognized as a major milk allergen. Generally, α-LA in the natural state combines with a calcium ion, however, some studies have shown that calcium ions can binding the other metal binding sites in α-LA as well. In our study, the optimal condition of calcium ion binding to α-LA and the change of structure and allergenicity were explored. By optimizing the conditions, the maximum calcium binding amounts of apo-α-LA were obtained in a ratio of 1:4. The structure of α-LA after removal of calcium obviously changed by the spectroscopic detection. For the digestive stability, there was no obvious change in three forms of α-LA. While the allergenic properties were characterized by IgG/IgE inhibition ELISA and the human basophil KU812 degranulation assay. The results showed that IgG and IgE binding decreased, and the degranulation capacity of basophils weakened. Based on these results, calcium binding to apo-α-LA can reduce the potential allergenic properties. PRACTICAL APPLICATIONS: By optimizing the conditions, bovine apo-α-LA can obtain the most calcium binding amount. And calcium binding to apo-α-LA can reduce the potential allergenic properties. Compared with α-LA in the natural state, calcium binding to α-LA not only can reduce the allergenic properties, but also play a role in calcium supplementation. It might be used to guide the development of hypoallergenic α-LA and provide a method to reduce the potential allergenic properties of α-LA.

Iron-induced chelation alleviates the potential allergenicity of ovotransferrin in a BALB/c mouse model.

Ovotransferrin (OVT) is one of the main egg allergens with 2 iron-binding sites. Several studies have demonstrated that iron-chelation decreased the allergenicity of milk allergen and birch pollen allergens. Therefore, we hypothesized that iron-chelation could also reduce the allergenicity of OVT. Apo-OVT (iron-free OVT, the natural state in egg white) and Holo-OVT (iron-chelated OVT) were prepared, and the allergenicity of them were assessed and compared using a BALB/c mouse model as well as dendritic cells (DCs) based on antigen uptake. Mice were orally sensitized with Apo-OVT or Holo-OVT using cholera toxin as adjuvant. Clinical signs of allergy, morphological structure of jejunum, specific antibody levels, mast cell protease-1 (mMCP-1) concentrations, cytokines and antigen uptake by DCs were determined after the mice were challenged with Apo-OVT or Holo-OVT. Results showed that both Apo-OVT and Holo-OVT induced intestinal allergy, but no systematic allergic symbols were observed. Serum levels of mouse mast cell protease-1 (mMCP-1) and specific IgE in Apo-OVT group were lower than in control group, and no significant difference between Apo-OVT group and Holo-OVT group (P>.05). The levels of OVT-specific IgG and IgG1, as well as the Th-1 cytokine interferon gamma and Th2-type cytokine interleukin-13 in Holo-OVT sensitized mice were significantly decreased compared to Apo-OVT group (P<.05), while no significant difference with control group (P>.05). However, DCs took in less Apo-OVT than Holo-OVT. Overall, iron-induced chelation could alleviate the potential allergenicity of OVT in vivo.

Influence of royal jelly on the reproductive function of puberty male rats.

The adverse effects of royal jelly on the reproductive system of puberty male rats were investigated. Royal jelly was daily administered by gavage to Sprague-Dawley rats at doses 200, 400, and 800 mg/kg for 4 weeks. The body weight and organ coefficients were determined. Sperm count, spermatozoa abnormality, and testicular histopathology were examined through light microscopy. Radioimmunoassay was used to detect serum hormones. The dietary exposure to royal jelly did not affect body weight, but the organ coefficients for the pituitary and testis in the high-dose group were decreased significantly compared with the control group, and significant changes in the microstructure of the testis were observed. No significant differences in sperm count were observed among all groups, however, the sperm deformity rate in the high-dose group increased significantly. Serum hormones in the high-dose group were significantly different from the control group. After royal jelly was stopped for 14 days, the adverse changes were partially reversed and returned to levels close to those in the control group. In conclusion, high-dose royal jelly oral administration for 4 weeks adversely affected the reproductive system of pubescent male rats, but the unfavorable effects are alleviated to some extent by cessation of administration.