Identification of Key Antioxidants of Free, Esterified, and Bound Phenolics in Walnut Kernel and Skin.

Walnut is a natural source of antioxidants. Its antioxidant capacity is determined by the distribution and composition of phenolics. The key phenolic antioxidants in various forms (free, esterified, and bound) in walnut kernel (particularly seed skin) are unknown. The phenolic compounds in twelve walnut cultivars were analyzed using ultra-performance liquid chromatography coupled with a triple quadrupole mass spectrometer in this study. A boosted regression tree analysis was used to identify the key antioxidants. Ellagic acid, gallic acid, catechin, ferulic acid, and epicatechin were abundant in the kernel and skin. The majority of phenolic acids were widely distributed in the free, esterified, and bound forms in the kernel but more concentrated in bound phenolics in the skin. The total phenolic levels of the three forms were positively correlated with antioxidant activities (R = 0.76-0.94, p < 0.05). Ellagic acid was the most important antioxidant in the kernel, accounting for more than 20%, 40%, and 15% of antioxidants, respectively. Caffeic acid was responsible for up to 25% of free phenolics and 40% of esterified phenolics in the skin. The differences in the antioxidant activity between the cultivars were explained by the total phenolics and key antioxidants. The identification of key antioxidants is critical for new walnut industrial applications and functional food design in food chemistry.

Efficacy of the therapy of 5-aminolevulinic acid photodynamic therapy combined with human umbilical cord mesenchymal stem cells on methicillin-resistant Staphylococcus aureus-infected wound in a diabetic mouse model.

BACKGROUND: A distressing issue of diabetic ulcer (DU) is its poor healing feature with limited clinical solutions. We have previously shown that 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is a promising alternative to the currently limited measures for DU. Mesenchymal stem cells (MSCs) transplantation has been believed to impose certain therapeutic effect on restoration of injury. Thus, this study aims to explore whether the combination of MSCs and ALA-PDT will exert a more advanced curative effect on DU. METHODS: Diabetic mice were induced by intraperitoneal injection of streptozotocin (STZ, 60 mg/kg/d) for consecutive 5 days. A full-thickness skin injury (diameter 6 mm) was created in the center of the back of each mouse, and then 10 µl of methicillin-resistant Staphylococcus aureus (MRSA) suspension was added to establish an infected DU model. All DU models were randomly divided into four groups: Untreated group, MSCs group, ALA-PDT group, and ALA-PDT combined with human umbilical cord mesenchymal stem cells (hUC-MSCs) (ALA-PDT + MSCs) group. The wound sizes were recorded by a digital camera, and the healing rates were calculated using Image J software. Bacterial loads on wounds were measured using CFU (Colony forming units) analysis. The epithelialization, inflammatory cells infiltration and granulation tissue formation were monitored by Haematoxylin and eosin (H&E) staining, and the corresponding semi-quantitative score was matched. Growth and pro-inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Either ALA-PDT or injection of hUC-MSCs resulted in a rapid wound closure compared with the untreated, while their combination brought about the most prominent healing. On day 12, healing rates of the untreated, MSCs, ALA-PDT and ALA-PDT + MSCs were 40.56% ± 7.06%, 74.23 ± 4.83%, 84.03 ± 3.53%, 99.67 ± 0.49%, respectively. The bacterial burden reductions were approximately 1.58 logs (97.36%, P < 0.05), 2.34 logs (99.54%, P < 0.01), 4.50 logs (nearly 100%, P < 0.001) for MSCs, ALA-PDT and ALA-PDT + MSCs, respectively. Histology revealed reduced inflammatory cells and improved collagen precipitation and angiogenesis after hUC-MSCs and ALA-PDT treatment compared to the untreated. The combined therapy leaded to a more intact epithelium, similar to the healthy. Finally, ELISA revealed that the property of ALA-PDT to stimulate transforming growth factor-ß1 (TGF-ß1) and vascular endothelial growth factor (VEGF) and inhibit IL (interleukin) -1ß and IL-6 outweighed that of hUC-MSCs, and this function of the combination overwhelmed that of any single therapy. CONCLUSIONS: Our findings indicated that the strategy of combining ALA-PDT with hUC-MSCs possessed a significantly enhanced therapeutic effect over either single therapy, providing a promising innovative therapeutic candidate for refractory wounds.

Characterization of iron walnut in different regions of China based on phytochemical composition.

Little is known about the phytochemical composition of iron walnuts. Differences in the geographical origin of iron walnuts associated with economic benefits should also be examined. In this study, the phytochemical composition (fatty acids, Vitamin E, total polyphenols and flavonoids, amino acids, and minerals) of iron walnuts in China was investigated. The results showed that there were significant differences (p < 0.05) in the phytochemical composition of iron walnut oils and flours from different regions. Positive (r > 0.5, p < 0.05) and negative (r < - 0.5, p < 0.05) correlations were found between amino acids/minerals and amino acids/oleic acid, with the highest correlation coefficient (r = 0.742, p < 0.05) between Cu and tyrosine. In addition, based on the 12 phytochemical fingerprints selected by random forest, a geographical-origin identification model for iron walnuts was established, with a corresponding correct classification rate of 96.6%. The top three phytochemical fingerprints for the geographical-origin identification of iron walnut were microelements, macroelements, and antioxidant composition, with contribution rates of 61.7%, 18.1%, and 9.9%, respectively.

Phenolic profiles and antioxidant activities of free, esterified and bound phenolic compounds in walnut kernel.

The free, esterified and bound forms of 37 phenolic compounds (including hydroxybenzoic acid, hydroxycinnamic acids, flavanols, flavonols and flavones) from walnut kernel (Juglans regia L.) were investigated in this study. Results showed that the majority of walnut phenolics were presented in the free form (51.1%-68.1%), followed by bound (21.0%-38.0%) and esterified forms (9.7%-18.7%). Ellagic acid, gallic acid, ferulic acid, sinapic acid and caffeic acid were widely distributed in three forms. Differently, jeuglone, kaempferol, quercetin-7-o-ß-d-glucoside and dihydroquercetin were only found in free phenolics. Among the three forms, free phenolics had the highest radical scavenging activity (IC50: DPPH, 15.5 µg/ml; ABTS, 13.6 µg/ml). The correlation coefficients between the antioxidant activities of phenolics and their corresponding contents were 0.82-0.92. More soluble phenolics (free and esterified forms) could be extracted by acetone, while methanol was better at extracting insoluble bound phenolics.

Electrospun frogspawn structured membrane for gravity-driven oil-water separation.

The aim of this study is to prepare a fibrous membrane scaffold that possesses a frogspawn structure for high-efficiency oil-water separation. Polyamic acid was first electrospun onto a rotating wheel-collector to obtain the fibrous membrane. Subsequently, post-processing by immersion in a polydimethylsiloxane solution and a silica nanoparticles suspension, followed by a thermal treatment generated a frogspawn-structured fibrous membrane. The obtained membrane achieved superhydrophobicity and superoleophilicity, with the water contact angle as high as 155.75° and the oil contact angle lower than 10°. The separation efficiencies of the membrane were higher than 99.55% and the permeate flux was maintained at greater than 4400 L/m2∙h after 20 separation cycles. Additionally, the wettability studies suggested the membrane exhibits high stability because it can resist damages due to high temperature (150 °C), acid/basic conditions and organic/inorganic solvents. These findings indicated that this composite membrane has great potential for use in gravity-driven oil-water separation and can extend the range of its application for treatments of oil spills incident, oily wastewater and spent liquor.

Risk assessment and prediction for toxic heavy metals in chestnut and growth soil from China.

BACKGROUND: Toxic heavy metals (THMs) cause severe environmental hazards and threaten human health through various consumption of food stuff. However, little is known of THMs in chestnuts. In this study, the risk assessment and prediction of THMs [lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd) and mercury (Hg)] in chestnuts and growth soils from China were investigated. RESULTS: The main detected THMs in chestnuts and growth soils were As and Cd. The total pollution levels of the five THMs (Nemerow pollution indexes, NPIs) were 0.062 and 1.06, respectively. The dietary risks for children were higher than those of adults, especially short-term non-carcinogenic risk. The main combined risks from the relationships between THMs were Pb-Cr (r = 0.85, P < 0.01) in chestnuts and Pb-As (r = 0.59, P < 0.01) in growth soils. The risk source was found to be the uptake effect of THMs from soil to chestnut, with the highest bioaccumulation factors (BCFs) of Cd (0.254). Several comprehensive risk models were established with the highest coefficient of determination (R2 ) of 0.79. In addition, the main contribution rates of different soil parameters to comprehensive risk of THMs uptake were 49.8% (Cd), 23.4% (pH), 13.8% (Cr) and 13.0% (organic carbon). CONCLUSION: The total pollution levels of THMs fell outside of the safety domain in growth soils. Furthermore, more attention needs to be paid to Cd pollution owing to its low environment background value and high accumulation ability. Three main soil parameters (Cr content, pH, organic carbon) played important roles in the formations and accumulations of THMs in chestnuts. © 2019 Society of Chemical Industry.