Antimicrobial carbon dots/pectin-based hydrogel for promoting healing processes in multidrug-resistant bacteria-infected wounds.

Multidrug-resistant (MDR) bacterial infections have become a significant threat to global healthcare systems. Here, we developed a highly efficient antimicrobial hydrogel using environmentally friendly garlic carbon dots, pectin, and acrylic acid. The hydrogel had a porous three-dimensional network structure, which endowed it with good mechanical properties and compression recovery performance. The hydrogel could adhere closely to skin tissues and had an equilibrium swelling ratio of 6.21, indicating its potential as a wound dressing. In particular, the bactericidal efficacy following 24-h contact against two MDR bacteria could exceed 99.99 %. When the hydrogel was applied to epidermal wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) on mice, a remarkable healing rate of 93.29 % was observed after 10 days. This was better than the effectiveness of the traditionally used antibiotic kanamycin, which resulted in a healing rate of 70.36 %. In vitro cytotoxicity testing and hemolysis assay demonstrated a high biocompatibility. This was further proved by the in vivo assay where no toxic side effects were observed on the heart, liver, spleen, lung, or kidney of mice. This eco-friendly and easy-to-prepare food-inspired hydrogel provides an idea for the rational use of food and food by-products as a wound dressing to control MDR bacterial infections.

Advances on Cyclocarya paliurus polyphenols: Extraction, structures, bioactivities and future perspectives.

Cyclocaryapaliurus (C. paliurus) is an edible and medicinal plant, distributed in southern China. As a kind of new food raw material, the leaves of C. paliurus are processed as tea products in daily life. C. paliurus is recognized as a good source to polyphenols, showing excellent bioactivities, which has attracted more and more attention. Polyphenols are important functional bioactive components in C. paliurus. C. paliurus polyphenols perform nutritional functions in anti-diabetes, anti-hyperlipidemic, anti-obesity, anti-oxidant, and other activities. In this review, we summarize the research progress of extraction technologies, structural characteristics, and bioactivities of C. paliurus polyphenols. Other potential functions of C. paliurus polyphenols are prospected. This review provides a reference for further research and applications of C. paliurus polyphenols in a field of functional food and medicines.

Oridonin prevents oxidative stress-induced endothelial injury via promoting Nrf-2 pathway in ischaemic stroke.

Oridonin, a natural diterpenoid compound extracted from a Chinese herb, has been proved to exert anti-oxidative stress effects in various disease models. The aim of the present study was to investigate the protective effects of oridonin on oxidative stress-induced endothelial injury in ischaemic stroke. We found oridonin repaired blood-brain barrier (BBB) integrity presented with upregulation of tight junction proteins (TJ proteins) expression, inhibited the infiltration of periphery inflammatory cells and neuroinflammation and thereby reduced infarct volume in ischaemic stroke mice. Furthermore, our results showed that oridonin could protect against oxidative stress-induced endothelial injury via promoting nuclear translocation of nuclear factor-erythroid 2 related factor 2 (Nrf-2). The specific mechanism could be the activation of AKT(Ser473)/GSK3ß(Ser9)/Fyn signalling pathway. Our findings revealed the therapeutic effect and mechanism of oridonin in ischaemic stroke, which provided fundamental evidence for developing the extracted compound of Chinese herbal medicine into an innovative drug for ischaemic stroke treatment.

Adsorption of aflatoxins and ochratoxins in edible vegetable oils with dopamine-coated magnetic multi-walled carbon nanotubes.

A new, green, and cost-effective magnetic solid-phase extraction of aflatoxins and ochratoxins from edible vegetable oils samples was developed using polydopamine-coated magnetic multi-walled carbon nanotubes (PDA@Fe3O4-MWCNTs) as the absorbent. PDA@Fe3O4-MWCNTs nanomaterials were prepared by chemical co-precipitation and in situ oxidation and self-polymerization of dopamine and was characterized. Factors affecting MSPE and the adsorption behavior of the adsorbent to mycotoxins were studied, and the optimal extraction conditions of MSPE and the complexity of the adsorption process were determined. Based on this, the magnetic solid-phase extraction-high-performance liquid chromatography-fluorescence detection method (MSPE-HPLC-FLD) was established for determining six mycotoxins [aflatoxin B1 (AFB1), AFB2, AFG1, and AFG2, and ochratoxin A (OTA) and OTB)] in vegetable oils. The recovery was 70.15%~89.25%, and RSD was ≤6.4%. PDA@Fe3O4-MWCNTs showed a high affinity toward aflatoxins and ochratoxins, allowing selective extraction and quantification of aflatoxins and ochratoxins from complex sample matrices.

Chemical and toxicological alterations of zearalenone under ozone treatment.

Our work mainly studied the elimination of zearalenone (ZEN) from corn flour by ozone treatment. We found four degradation products, after separation and identification by UPLC-ESI-QTOF-MS, named as Compound 1 (m/z 335.18), Compound 2 (m/z 351.19), Compound 3 (m/z 321.19) and Compound 4 (m/z 367.18). Then, one main transformation pathway was predicted on the basis of molecular weight and the reaction mechanism of ozone. We had also detected two of the degradation products by our modified UPLC-MS/MS method in real samples-contaminated corn flour. We screened the toxicity of the parent ZEN compound as well as the ozone induced decomposition products with BALB/c mice to evaluate the safety of our method in vivo. Therefore, aqueous ozone was demonstrated to effectively degrade ZEN and chemical structure alternations of ZEN after ozone treatment were predicted in both pure ZEN and real contaminated-corn flour samples. Considering the presence of the by-products formed, differences in the toxic effects on mice exposed to ZEN before and after the ozone treatment emphasise the significance of further study on the quality and toxicity of real food samples after ozone treatment.

Enzymatic amplification detection of peanut allergen Ara h1 using a stem-loop DNA biosensor modified with a chitosan-mutiwalled carbon nanotube nanocomposite and spongy gold film.

In this paper, a highly sensitive biosensor was constructed for peanut allergen Ara h1 detection. The biosensor was constructed by coating a glassy carbon electrode with a chitosan-mutiwalled carbon nanotube nanocomposite and then adding a spongy gold film via electro-deposition to increase the effective area. The probe switched from an "on" to an "off" state in the presence of target DNA, which detached biotin from the electrode surface. This also detached streptavidin-horseradish peroxidase (HRP-SA), which was bound to the electrode via specific interaction with biotin. The HRP-SA catalyzed chemical oxidation of hydroquinone by H2O2 to form benzoquinone, and when it was detached, electrochemical reduction of the signal of benzoquinone could be used to monitor DNA hybridization via chronoamperometry. Under optimum conditions, a wide dynamic detection range (3.91 × 10(-17)-1.25 × 10(-15) mol L(-1)) and a low detection limit (1.3 × 10(-17) mol L(-1)) were achieved for the complementary sequence. Furthermore, the DNA biosensor exhibited an excellent ability to discriminate between a complementary target and a one-base mismatch or non-complementary sequence. The sensor was successfully applied to Ara h1 analysis in peanuts.

Multilayer graphene-gold nanocomposite modified stem-loop DNA biosensor for peanut allergen-Ara h1 detection.

In this study, we developed an electrochemically-amplified, stem-loop DNA biosensor to detect the peanut allergen Ara h1. Specifically, we electrodeposited a multilayer graphene-gold nanocomposite onto a glassy carbon electrode and then immobilised a thiolated hairpin DNA-biotin probe onto the modified electrode surface. The multilayer graphene-gold composite has good dispersion ability, and can amplify the electrochemical signal due to its high electron-transfer efficiency. The probe was switched to an "off" state in the presence of target DNA. The prepared biosensor demonstrated a linear response ranging from 10(-16) to 10(-13)M, with an ultrasensitive detection limit of 0.041 fM. Moreover, the biosensor showed excellent selectivity, as well as the ability to discriminate between a complementary target and a one-base mismatch or non-complementary sequence. Results show that this prepared DNA biosensor can be successfully used to detect the peanut allergen Ara h1 in a peanut milk beverage. Findings can be applied to the prevention of allergic reactions, thus improving human health and safety.

Paeoniflorin protects against ischemia-induced brain damages in rats via inhibiting MAPKs/NF-κB-mediated inflammatory responses.

Paeoniflorin (PF), the principal component of Paeoniae Radix prescribed in traditional Chinese medicine, has been reported to exhibit many pharmacological effects including protection against ischemic injury. However, the mechanisms underlying the protective effects of PF on cerebral ischemia are still under investigation. The present study showed that PF treatment for 14 days could significantly inhibit transient middle cerebral artery occlusion (MCAO)-induced over-activation of astrocytes and microglia, and prevented up-regulations of pro-inflamamtory mediators (TNFα, IL-1ß, iNOS, COX(2) and 5-LOX) in plasma and brain. Further study demonstrated that chronic treatment with PF suppressed the activations of JNK and p38 MAPK, but enhanced ERK activation. And PF could reverse ischemia-induced activation of NF-κB signaling pathway. Moreover, our in vitro study revealed that PF treatment protected against TNFα-induced cell apoptosis and neuronal loss. Taken together, the present study demonstrates that PF produces a delayed protection in the ischemia-injured rats via inhibiting MAPKs/NF-κB mediated peripheral and cerebral inflammatory response. Our study reveals that PF might be a potential neuroprotective agent for stroke.

Electrochemical detection of peanut allergen Ara h 1 using a sensitive DNA biosensor based on stem-loop probe.

A novel electrochemical DNA sensor was developed by using a stem-loop probe for peanut allergen Ara h 1 detection. The probe was modified with a thiol at its 5' end and a biotin at its 3' end. The biotin-tagged "molecular beacon"-like probe was attached to the surface of a gold electrode to form a stem-loop structure by self-assembly through facile gold-thiol affinity. 6-Mercaptohexanol (MCH) was used to cover the remnant bare region. The stem--loop probe was "closed" when the target was absent, and then the hybridization of the target induced the conformational change to "open", along with the biotin at its 3' end moved away from the electrode surface. The probe conformational change process was verified by circular dichroism (CD); meanwhile, electron-transfer efficiency changes between probe and electrode were proved by electrochemical impedance spectroscopy (EIS). The detection limit of this method was 0.35 fM with the linear response ranging from 10(-15) to 10(-10) M. Moreover, a complementary target could be discriminated from one-base mismatch and noncomplementarity. The proposed strategy has been successfully applied to detect Ara h 1 in the peanut DNA extracts of peanut milk beverage, and the concentration of it was 3.2 × 10(-13) mol/L.

Neuroprotective effects of berberine on stroke models in vitro and in vivo.

Berberine is an alkaloid derived from herb medicine Coptidis Rhizom. Although there are increasing evidences that berberine exhibits neuroprotective effects against ischemic brain damage, little is known about the mechanism. In this study, we investigated the effect of berberine on ischemic injury in a middle cerebral artery occlusion (MCAO) model. We found that berberine improved neurological outcome and reduced ischemia/reperfusion (I/R)-induced cerebral infarction 48h after MCAO. The protective effect of berberine was confirmed in in vitro study. Berberine protected PC12 cells against oxygen-glucose deprivation (OGD)-induced injury. The results showed that berberine inhibited reactive oxygen species (ROS) generation, and subsequent release of pro-apoptotic factor cytochrome c and apoptosis-inducing factors (AIFs) evoked by OGD. Findings of this study suggest that berberine protects against ischemic brain injury by decreasing the intracellular ROS level and subsequently inhibiting mitochondrial apoptotic pathway.

Effect of Polygala tenuifolia root extract on scopolamine-induced impairment of rat spatial cognition in an eight-arm radial maze task.

The effects of Polygala tenuifolia root fractions and the acyl groups of its constituents on the retrieval process of spatial cognition in rats were studied using an eight-arm radial maze task. Oral administration of a precipitate fraction (PTB) obtained by concentration of the n-BuOH-soluble portion from the extract of the roots significantly decreased the number of total errors (TEs) and that of working memory errors (WMEs) at doses of 100 mg/kg and 200 mg/kg. However, it caused no significant decrease in the number of reference memory errors (RMEs). In addition, the saponin-rich fraction (PTBM) obtained by purification of PTB also showed significant decreases in TEs and WMEs at a dose of 100 mg/kg. Among the cinnamic acid derivatives present as the acyl groups in the P. tenuifolia constituents, sinapic acid (SNPA) significantly decreased TEs and WMEs at doses of 10 to 100 mg/kg. These results indicated that P. tenuifolia extracts, PTB and PTBM, and SNPA had a beneficial effect on the memory impairment induced by dysfunction of the cholinergic system in the brain. The memory improvement in the scopolamine-induced memory impairment seen in the radial maze performance was due to improvement in the short-term memory. A contribution of some constituents other than SNPA to the memory improvement was also suggested.