A Supramolecular Assembly of EGCG for Long-Term Treatment of Allergic Rhinitis.

Allergic rhinitis (AR) is a type-I hypersensitivity disease mediated by immunoglobulin E (IgE). Although antihistamines, glucocorticoids, leukotriene receptor antagonists, and other drugs are widely used to treat AR, the various adverse side effects of long-term use of these drugs should not be ignored. Therefore, more effective and safe natural alternative strategies are urgently needed. To this end, this study designed a nanosupramolecular delivery system composed of ß-cyclodextrin supramolecular polymer (PCD), thiolated chitosan (TCS), and natural polyphenol epigallocatechin gallate (EGCG) for intranasal topical continuous treatment of AR. The TCS/PCD@EGCG nanocarriers exhibited an excellent performance in terms of retention and permeability in the nasal mucosa and released the vast majority of EGCG responsively in the nasal microenvironment, thus resulting in the significantly high antibacterial and antioxidant capacities. According to the in vitro model, compared with free EGCG, TCS/PCD@EGCG inhibited mast cell activity and abnormal histamine secretion in a more long-term and sustained manner. According to the in vivo model, whether in the presence of continuous or intermittent administration, TCS/PCD@EGCG substantially inhibited the secretion of allergenic factors and inflammatory factors, mitigated the pathological changes of nasal mucosa, alleviated the symptoms of rhinitis in mice, and produced a satisfactory therapeutic effect on AR. In particular, the therapeutic effect of TCS/PCD@EGCG systems were even superior to that of budesonide during intermittent treatment. Therefore, the TCS/PCD@EGCG nanocarrier is a potential long-lasting antiallergic medicine for the treatment of AR.

Double-Layer Hydrogel with Glucose-Activated Two-Stage ROS Regulating Properties for Programmed Diabetic Wound Healing.

Slow healing of wounds induces great pain in diabetic patients. However, developing new approaches to promote diabetic wound healing is still one of the toughest challenges in the medical field. Here, we constructed a new double-layer hydrogel to effectively regulate reactive oxygen species (ROS) on the wound and promote diabetic wound healing. The inner layer contains glucose oxidase (Gox), ferrocene-modified quaternary ammonium chitosan (Fc-QCs), and poly(ß-cyclodextrin) (Pß-CD), which is used to generate hydroxyl radicals (•OH) for antibacterial in the early stage of wound healing and collapses gradually. The outer layer is composed of gelatin and dopamine. In the later stage of wound healing, the outer layer contacts the skin, which is beneficial for ROS clearance on the wound. Antibacterial, ROS scavenging, and wound healing experiments have shown that the double-layer hydrogel possesses two-stage ROS regulating properties for programmed diabetic wound healing. In conclusion, it will be one of the most potential dressings for treating diabetic wounds in the future.

Poly ß-Cyclodextrin/Quaternary Ammoniated Chitosan Cryogel with a Porous Structure for Effective Hemostasis.

Uncontrolled bleeding is one of the most important causes threatening human health, but quick hemostasis remains a challenge. We prepared porous cryogels with poly ß-cyclodextrin (Pß-CD) and quaternary ammoniated chitosan (QCs). Pß-CD acts as a "water-grabbing agent" to assist QCs' ability to absorb and concentrate blood rapidly. The rat-tail amputation model and liver injury model exhibited that cryogels had excellent hemostatic performance. Moreover, cryogels showed good antibacterial activity and biocompatibility. Therefore, these cryogels can be used as potential hemostatic materials.

Effects of exogenous thiocyanate on mineral nutrients, antioxidative responses and free amino acids in rice seedlings.

The effects of exogenous thiocyanate (SCN(-)) on amino acids composition, content of mineral nutrients and antioxidative systems in plants were investigated. Young rice seedlings (Oryza sativa L. cv. XZX 45) were grown in nutrient solutions amended with potassium thiocyanate (KSCN). Activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in plant materials were analyzed in vivo. Mineral nutrients and free amino acids in rice seedlings were also measured to determine metabolic responses to SCN(-) exposure. A significant reduction in transpiration and relative growth was recorded with all treatments (p < 0.05), while changes of total chlorophyll content in leaves was negligible (p > 0.05). SCN-induced toxicity appeared to be more sensitive to activities of POD in shoots and APX activities in roots than the others. The content of nutrient elements in rice seedlings exposed to exogenous SCN(-) was variable, while the effects were more evident at the highest SCN-treatment (p < 0.05). Although the change of total free amino acids in shoots of SCN-exposed seedlings was negligible (p > 0.05), responses of different amino acids to SCN(-) application were quite different. Among fifteen free amino acids detected, serine (Ser), proline (Pro), and methionine (Met) increased, while asparagine (Asp) decreased with an increase of the doses of SCN(-) supplied. Phyto-transport of SCN(-) was apparent and the removal rates were positively correlated to the doses, suggesting that phyto-assimilation of SCN(-) is an enzymatic process through a potentially un-identified degradation pathway.

Evidence of iron cyanides as supplementary nitrogen source to rice seedlings.

The effect of iron cyanides on activities of nitrate reductase (NR) and glutamine synthetase (GS) of plants was investigated. Young rice seedlings (Oryza sativa L. cv. XZX 45) were grown in the nutrient solutions containing KNO(3) or NH(4)Cl and treated with ferro-cyanide [K(4)Fe(CN)(6)] or ferri-cyanide [K(3)Fe(CN)(6)]. Total cyanide and free cyanide in solutions and in plant materials were analyzed. Activities of NR and GS in different parts of plants were assayed in vivo. Results indicated that all rice seedlings exposed to either ferro- or ferri-cyanide showed positive growth. The phyto-assimilation rates of both iron cyanide species by rice seedlings were positively correlated to the doses supplied. Seedlings grown on NO(3)(-) showed significantly higher assimilatory potential for both ferro- and ferri-cyanide than those on NH(4)(+). Rice seedlings grown on NH(4)(+)-containing nutrient solution accumulated more cyanide in plant materials, majority being in roots rather than shoots, than these grown on NO(3)(-)-containing nutrient solution, suggesting that the presence of ammonium (NH(4)(+)) in the nutrient solution caused a negative impact on botanical assimilation of both iron cyanides. Sensitivity of NR and GS in rice seedlings exposed to ferro- and ferri-cyanide was identical, where conspicuous effects were only observed at the highest concentration supplied. The evidence offered here suggests that both iron cyanides can be a supplementary source of nitrogen to plant nutrition.

Activities of nitrate reductase and glutamine synthetase in rice seedlings during cyanide metabolism.

A study was conducted to investigate activities of nitrate reductase (NR) and glutamine synthetase (GS) in plants during cyanide metabolism. Young rice seedlings (Oryza sativa L. cv. XZX 45) were grown in the nutrient solutions containing KNO(3) or NH(4)Cl and treated with free cyanide (KCN). Cyanide in solutions and in plant materials was analyzed to estimate the phyto-assimilation potential. Activities of NR and GS in different parts of rice seedlings were assayed in vivo. Seedlings grown on NH(4)(+) showed significantly higher relative growth rate than those on NO(3)(-) (p<0.05) in the presence of exogenous cyanide. The metabolic rates of cyanide by seedlings were all positively correlated to the concentrations supplied. A negligible difference was observed between the two treatments with nitrate and ammonium (p>0.05). Enzymatic assays showed that cyanide (≥0.97mg CN L(-1)) impaired NR activity significantly in both roots and shoots (p<0.05). The effect of cyanide on GS activity in roots was more evident at 1.93mg CN L(-1), suggesting that NR activity was more susceptible to change from cyanide application than GS activity. The results observed here suggest that the exogenous cyanide, which to a certain level has a beneficial role in plant nutrition.

Phytotoxicity of thiocyanate to rice seedlings.

The acute toxicity of potassium thiocyanate (KSCN) and ammonium thiocyanate (NH(4)SCN) to rice seedlings was tested. Hydroponically-grown plants showed different responses to the two species of thiocyanate. NH(4)SCN caused more severe stress to rice seedlings than KSCN. A significant reduction in transpiration and relative growth was observed with all NH(4)SCN treatments (p < 0.01), while the effect of KSCN on rice seedlings was more evident at greater than 100 mg SCN/L (p < 0.01). Both chemicals had a negligible effect on total chlorophyll content in shoots of rice seedlings (p > 0.05). Although phyto-transport of thiocyanate was apparent, rice seedlings showed significantly higher removal potential for NH(4)SCN than KSCN.