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In recent years, nanozymes have attracted particular interest and attention as catalysts because of their high catalytic efficiency and stability compared with natural enzymes, whereas how to use simple methods to further improve the catalytic activity of nanozymes is still challenging. In this work, we report a trimetallic metal–organic framework (MOF) based on Fe, Co and Ni, which was prepared by replacing partial original Fe nodes of the Fe-MOF with Co and Ni nodes. The obtained FeCoNi-MOF shows both oxidase-like activity and peroxidase-like activity. FeCoNi-MOF can not only oxidize the chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) to its blue oxidation product oxTMB directly, but also catalyze the activation of H2O2 to oxidize the TMB. Compared with corresponding monometallic/bimetallic MOFs, the FeCoNi-MOF with equimolar metals hereby prepared exhibited higher peroxidase-like activity, faster colorimetric reaction speed (1.26–2.57 folds), shorter reaction time (20 min) and stronger affinity with TMB (2.50–5.89 folds) and H2O2 (1.73–3.94 folds), owing to the splendid synergistic electron transfer effect between Fe, Co and Ni. Considering its outstanding advantages, a promising FeCoNi-MOF-based sensing platform has been designated for the colorimetric detection of the biomarker H2O2 and environmental pollutant TP, and lower limits of detection (LODs) (1.75 μM for H2O2 and 0.045 μM for TP) and wider linear ranges (6–800 μM for H2O2 and 0.5–80 μM for TP) were obtained. In addition, the newly constructed colorimetric platform for TP has been applied successfully for the determination of TP in real water samples with average recoveries ranging from 94.6% to 112.1%. Finally, the colorimetric sensing platform based on FeCoNi-MOF is converted to a cost-effective paper strip sensor, which renders the detection of TP more rapid and convenient.

The present study aimed to increase the content of minor ginsenosides and enhance the anti-colorectal cancer activity of ginsenosides via biotransformation by Lactiplantibacillus plantarum MB11 screened from fermented foods. A subcutaneous transplantation tumor model of murine colorectal cancer CT26 cells was established in mice to study the anticarcinogenic activities and mechanism of fermented total ginsenosides (FTGs). The results showed that L. plantarum MB11 fermentation increased the content of minor ginsenosides and decreased that of major ginsenosides. FTGs reduced the tumor weight and size compared with the model group. Immunofluorescence and TdT-mediated dUTP nick end labeling (TUNEL) analysis showed that FTGs significantly increase the number of caspase-3 cells in tumor tissue and induce cell apoptosis. Mechanically, FTGs activate AMPK/mTOR autophagy pathway and regulate JAK2/STAT3 and Bax/Bcl-2/caspase-3 apoptosis pathway. Overall, fermentation with L. plantarum MB11 enhanced minor ginsenosides in total ginsenosides, and FTGs induced subcutaneous transplantation tumor autophagy and apoptosis in mice.

The emergence and fast development of carbon dots (CDs) provide an unprecedented opportunity for applications in the field of photoelectricity, but their practicability still suffers from complicated synthesis procedures and the substrate dependence of solid-state fluorescence. In this study, we design a unique microwave-assisted solid-phase synthesis route for preparing tunable fluorescent CD powders with yellow, orange, and red fluorescence (Y-CDs, O-CDs, R-CDs) by simply adjusting the mass ratio of reactants, a method which is suitable for the large-scale synthesis of CDs. The Y-/O-/R-CDs were systematically characterized using physics and spectroscopy techniques. Based on the perfect solid-state fluorescence performance of the proposed fluorescent CD powders, the Y-/O-/R-CDs were successfully applied for the construction of multi-color and white light-emitting diode devices at low cost. Furthermore, the Y-CDs displayed much higher yield and luminous efficiency than the O-CDs and R-CDs and were further used for fingerprint identification on the surfaces of glass sheets and tinfoil. In addition, the R-CD aqueous solution fluorescence is sensitive to pH, suggesting its use as a pH indicator for monitoring intracellular pH fluctuations. The proposed series of fluorescent powders composed of CDs may herald a new era in the application of optical components and criminal investigation fields.

The renewable-energy-driven integration of hydrogen production and biomass conversion into value-added products is desirable for the current global energy transition, but still a challenge. Herein, carbon-coated CoO–Co heterojunction arrays were built on copper foam (CoO–Co@C/CF) by the carbothermal reduction to catalyze the hydrogen evolution reaction (HER) coupled with a 5-hydroxymethylfurfural electrooxidation reaction (HMFEOR). The electronic modulation induced by the CoO–Co heterojunction endows CoO–Co@C/CF with a powerful catalytic ability. CoO–Co@C/CF is energetic for HER, yielding an overpotential of 69 mV at 10 mA·cm−1 and Tafel slope of 58 mV·dec−1. Meanwhile, CoO–Co@C/CF delivers an excellent electrochemical activity for the selective conversion from HMF into 2,5-furandicarboxylic acid (FDCA), achieving a conversion of 100%, FDCA yield of 99.4% and faradaic efficiency of 99.4% at the lower oxidation potential, along with an excellent cycling stability. The integrated CoO–Co@C/CF||CoO–Co@C/CF configuration actualizes the H2O–HMF-coupled electrolysis at a satisfactory cell voltage of 1.448 V at 10 mA·cm−2. This work highlights the feasibility of engineering double active sites for the coupled electrolytic system.

The traditional herb Eleutherococcus henryi Oliv. is commonly used to treat inflammatory conditions including rheumatism, arthritis, and hepatitis, as well as mental fatigue and amnesia, according to traditional Chinese medicine (TCM) theory. Savinin is a natural lignan obtained from the roots of E. henryi. The present study was undertaken to determine whether savinin can relieve LPS-induced neuroinflammation and if so, what the mechanism is. Groups of male C57BL/6 mice were administered savinin (5, 10, 20 mg/kg) and DEX (10 mg/kg) by gavage once daily for a continuous 7 days. On the 5th day of continuous pre-administration, LPS (2.5 mg/kg) was injected into the lateral ventricles of the mice for modeling 48 h. We found that treatment with savinin decreased the levels of neuroinflammatory cytokines and histopathological alterations dramatically. Consequently, it improved the LPS-induced neuroinflammatory response in mice. Furthermore, savinin inhibited the up-regulated expression of related proteins in the activated MAPK/NF-κB and NLRP3 inflammasome signaling pathways caused by LPS. Docking studies demonstrated the binding of savinin to three receptors (MAPK, NF-κB and NLRP3) using a well-fitting mode. These findings suggest that savinin may suppress neuroinflammation induced by LPS in vivo via modulating MAPK/NF-κB and NLRP3 signaling pathways.

The 2-oxoglutarate-dependent dioxygenase (2-OGD) superfamily is one of the largest protein families in plants. The main oxidation reactions they catalyze in plants are hydroxylation, desaturation, demethylation, epimerization, and halogenation. Four members of the 2-OGD superfamily, i.e., flavonone 3β-hydroxylase (F3H), flavones synthase I (FNS I), flavonol synthase (FLS), and anthocyanidin synthase (ANS)/leucoanthocyanidin dioxygenase (LDOX), are present in the flavonoid pathway, catalyzing hydroxylation and desaturation reactions. In this review, we summarize the recent research progress on these proteins, from the discovery of their enzymatic activity, to their functional verification, to the analysis of the response they mediate in plants towards adversity. Substrate diversity analysis indicated that F3H, FNS Ⅰ, ANS/LDOX, and FLS perform their respective dominant functions in the flavonoid pathway, despite the presence of functional redundancy among them. The phylogenetic tree classified two types of FNS Ⅰ, one mainly performing FNS activity, and the other, a new type of FNS present in angiosperms, mainly involved in C-5 hydroxylation of SA. Additionally, a new class of LDOXs is highlighted, which can catalyze the conversion of (+)-catechin to cyanidin, further influencing the starter and extension unit composition of proanthocyanidins (PAs). The systematical description of the functional diversity and evolutionary relationship among these enzymes can facilitate the understanding of their impacts on plant metabolism. On the other hand, it provides molecular genetic evidence of the chemical evolution of flavonoids from lower to higher plants, promoting plant adaptation to harsh environments.

Influenza A virus is the main cause of worldwide epidemics and annual influenza outbreaks in humans. In this study, a virtual screen was performed to identify compounds that interact with the PB2 cap-binding domain (CBD) of influenza A polymerase. A virtual screening workflow based on Glide docking was used to screen an internal database containing 8417 molecules, and then the output compounds were selected based on solubility, absorbance, and structural fingerprints. Of the 16 compounds selected for biological evaluation, six compounds were identified that rescued cells from H1N1 virus-mediated death at non-cytotoxic concentrations, with EC50 values ranging from 2.5–55.43 μM, and that could bind to the PB2 CBD of H1N1, with Kd values ranging from 0.081–1.53 μM. Molecular dynamics (MD) simulations of the docking complexes of our active compounds revealed that each compound had its own binding characteristics that differed from those of VX-787. Our active compounds have novel structures and unique binding modes with PB2 proteins, and are suitable to serve as lead compounds for the development of PB2 inhibitors. An analysis of the MD simulation also helped us to identify the dominant amino acid residues that play a key role in binding the ligand to PB2, suggesting that we should focus on increasing and enhancing the interaction between inhibitors and these major amino acids during lead compound optimization to obtain more active PB2 inhibitors.

To discover novel inhibitors that target the influenza polymerase basic protein 2 (PB2) cap-binding domain (CBD), commercial ChemBridge compound libraries containing 384,796 compounds were screened using a cascade docking of LibDock–LigandFit–GOLD, and 60 compounds were selected for testing with cytopathic effect (CPE) inhibition assays and surface plasmon resonance (SPR) assay. Ten compounds were identified to rescue cells from H1N1 virus-mediated death at non-cytotoxic concentrations with EC50 values ranging from 0.30 to 67.65 μM and could bind to the PB2 CBD of H1N1 with Kd values ranging from 0.21 to 6.77 μM. Among these, four compounds (11D4, 12C5, 21A5, and 21B1) showed inhibition of a broad spectrum of influenza virus strains, including oseltamivir-resistant ones, the PR/8-R292K mutant (H1N1, recombinant oseltamivir-resistant strain), the PR/8-I38T mutant (H1N1, recombinant baloxavir-resistant strain), and the influenza B/Lee/40 virus strain. These compounds have novel chemical scaffolds and relatively small molecular weights and are suitable for optimization as lead compounds. Based on sequence and structure comparisons of PB2 CBDs of various influenza virus subtypes, we propose that the Phe323/Gln325, Asn429/Ser431, and Arg355/Gly357 mutations, particularly the Arg355/Gly357 mutation, have a marked impact on the selectivities of PB2 CBD-targeted inhibitors of influenza A and influenza B.

Yam yellow pigments (YP) are natural pigments formed during the storage of freshly cut yam (Dioscorea opposita) under certain conditions. The interaction of YP with calf thymus DNA (ctDNA) and its protective effect against DNA oxidative damage were investigated using multiple spectroscopic techniques, competitive binding experiments, viscosity measurements, and gel electrophoresis. Results showed that YP participated in intercalative binding with ctDNA. YP exhibited a protective effect against hydroxyl-induced DNA damage, which was attributed to the high hydroxyl radical scavenging activity of YP. Our findings improve our understanding of the mechanism of interaction between YP and ctDNA, and provide a theoretical basis for the application of YP in the food and drug industry.

A method using LC-ESI-IT-TOF/MS and LC/UV-ELSD was established to qualitatively analyze triterpene saponins obtained from the tea seed pomace (Camellia oleifera Abel). In addition, the quantitative analysis of oleiferasaponin A1 using LC/UV was developed. The purified total saponins did not exhibit any inhibitory effects at concentrations ranging from 0.1 to 10 mg/mL against the tested bacteria, except for Staphyloccocus aureus and Escherichia coli. By contrast, higher inhibitory activity was seen against the tested fungi, especially against Bipolaris maydis. Following treatment with an MIC value of 250 μg/mL for 24 h, the mycelial morphology was markedly shriveled in appearance or showed flattened and empty hyphae, with fractured cell walls, ruptured plasmalemma and cytoplasmic coagulation or leakage. These structural changes hindered the growth of mycelia.

Moderate and high microfluidization pressures (60 and 120 MPa) and different treatment times (once and twice) were used to investigate the effect of high-pressure microfluidization (HPM) treatment on the crystallization behavior and physical properties of binary mixtures of palm stearin (PS) and palm olein (PO). The polarized light microscopy (PLM), texture analyzer, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques were applied to analyze the changes in crystal network structure, hardness, polymorphism and thermal property of the control and treated blends. PLM results showed that HPM caused significant reductions in maximum crystal diameter in all treated blends, and thus led to changes in the crystal network structure, and finally caused higher hardness in than the control blends. The XRD study demonstrated that HPM altered crystalline polymorphism. The HPM-treated blends showed a predominance of the more stable β' form, which is of more interest for food applications, while the control blend had more α- and β-form. This result was further confirmed by DSC observations. These changes in crystallization behavior indicated that HPM treatment was more likely to modify the crystallization processes and nucleation mechanisms.

Starch was isolated from longan seeds of three widely distributed cultivars (Chuliang, Shixia, and Caopu) in China. Comparisons of the multi-level structure of the starch of longan seeds among various cultivars were made, and the relations between these structural and property characteristics are discussed. The isolated starch, accounting for 44.9–49.5% (w/w) in longan seeds, had an oval or an irregular polygonal shape with a smooth surface. Their chain-length distributions (CLDs) varied with longan cultivar; Chuliang showed a larger proportion of longer amylopectin chains with a degree of polymerization (DP) 30~100. This is attributed to the slightly higher relative crystallinity of Chuliang longan seed starch. Apparent differences were also detected in amylose structure. Caopu showed a higher amylose content than Chuliang and Shixia, resulting in its lower gelatinization temperatures and enthalpy change. All longan seed starch had a typical A-type crystal structure with relative crystallinity ranging 28.6–28.9%. For raw starch, Caopu showed the lowest digestion rate, followed by Chuliang; Shixia showed the highest. This is because Caopu had the highest amylose content. Chuliang had a more intact structure than Shixia, as suggested by its higher crystallinity, although they had similar amylose content. After being fully gelatinized, all starch showed a similar digestion process, indicating that the digestibility of gelatinized starch does not differ with starch source or structure.

A new triterpenoid saponin, named oleiferasaponin A2, was isolated and identified from Camellia oleifera defatted seeds. Oleiferasaponin A2 exhibited anti-hyperlipidemic activity on HepG2 cell lines. Further study of the hypolipidemic mechanism showed that oleiferasaponin A2 inhibited fatty acid synthesis by significantly down-regulating the expression of SREBP-1c, FAS and FAS protein, while dramatically promoting fatty acid β-oxidation by up-regulating the expression of ACOX-1, CPT-1 and ACOX-1 protein. Our results demonstrate that the oleiferasaponin A2 possesses potential medicinal value for hyperlipidemia treatment.

The effect of curing agent (6610) content and temperature on the rheological behavior of the epoxy resin CYD-128 was studied by DSC analysis and viscosity experiments. The results show that the resin system meets the requirements of processing technology. A complete reaction occurs when the curing agent content (40 parts per hundred resin, phr) is a little higher than the theoretical value (33.33 phr), while the degree of reaction of the resin system is reduced when the curing agent content is lower (25.00 phr) than theoretical value. However, excessive curing agent (50.00 phr) results in a lower reaction rate. Curing agent content has little influence on gel time when curing agent content exceeded 33.33 phr and the temperature was less than 70 °C. The isothermal viscosity-time curves shift towards the –x axis when the temperature rises from 50 °C to 80 °C. Meanwhile, higher temperature results in higher reaction rates.

In this study, the effects of frozen (−18 °C) storage time on molecular weight, size distribution, conformation, free amino groups and free sulfhydryl groups of gluten were studied by small-angle X-ray scattering (SAXS), multi-angle laser light scattering (MALLS) in conjunction with a size exclusion chromatography (SEC) and spectrophotometrically. The results showed that the gluten dissolved in 50 mM acetic acid appeared to be similar to quasi-spherical of the chain conformation and the slope of the conformation plot decreased during the storage. Both the molecular weight and radius of gyration of the frozen gluten decreased with the storage time showing a depolymerization in the high molecular weight fraction of gluten (105 Da ~ 109 Da). Therefore, at constant molecular weight the change of the chain conformation did not show a clear correlation with the storage time. The free amino groups content changed little and the free sulfhydryl groups content of the gluten increased from 9.8 μmol/g for the control to 12.87 μmol/g for 120-day-stored gluten, indicating that the water redistribution and ice recrystallization lead to the breakage of the disulphide bonds and may be one of the reasons for the depolymerization of gluten polymer.

The prebiotic potential of longan juice obtained by a commercial Viscozyme L for conversion of constituent sucrose to fructo-oligosaccharide was investigated. The physicochemical properties and carbohydrate composition of the longan juice was evaluated before and after enzymatic treatment. The stimulation effects of the treated longan juice on probiotic bacteria growth were also studied in vitro. The results showed that total soluble solids, yield and clarity of longan juice were all significantly improved after enzyme treatment. The water-soluble polysaccharide content, including pectin, was significantly increased. Compared with the natural longan pulp, the enzyme treated juice showed a significant decrease in sucrose content. Substantial fructo-oligosaccharides including 1-kestose and nystose were synthesized after enzyme treatment. The molecular weight distribution and the monosaccharide composition of the water-soluble polysaccharide were significantly changed by enzyme treatment. The treated longan juice and its ethanol-soluble sugar fraction promoted the growth of Streptococus thermophiles, Lactobacillus acidophilus and Lactobacillus delbrueckii, showing a good potential of the treated longan juice for producing functional foods and nutraceuticals.

Anthocyanidin reductase (ANR) is a key enzyme in the ANR biosynthetic pathway of flavan-3-ols and proanthocyanidins (PAs) in plants. Herein, we report characterization of the ANR pathway of flavan-3-ols in Shuchazao tea (Camellia sinesis), which is an elite and widely grown cultivar in China and is rich in flavan-3-ols providing with high nutritional value to human health. In our study, metabolic profiling was preformed to identify two conjugates and four aglycones of flavan-3-ols: (−)-epigallocatechin-gallate [(−)-EGCG], (−)-epicatechin-gallate [(−)-ECG], (−)-epigallocatechin [(−)-EGC], (−)-epicatechin [(−)-EC], (+)-catechin [(+)-Ca], and (+)-gallocatechin [(+)-GC], of which (−)-EGCG, (−)-ECG, (−)-EGC, and (−)-EC accounted for 70–85% of total flavan-3-ols in different tissues. Crude ANR enzyme was extracted from young leaves. Enzymatic assays showed that crude ANR extracts catalyzed cyanidin and delphinidin to (−)-EC and (−)-Ca and (−)-EGC and (−)-GC, respectively, in which (−)-EC and (−)-EGC were major products. Moreover, two ANR cDNAs were cloned from leaves, namely CssANRa and CssANRb. His-Tag fused recombinant CssANRa and CssANRb converted cyanidin and delphinidin to (−)-EC and (−)-Ca and (−)-EGC and (−)-GC, respectively. In addition, (+)-EC was observed from the catalysis of recombinant CssANRa and CssANRb. Further overexpression of the two genes in tobacco led to the formation of PAs in flowers and the reduction of anthocyanins. Taken together, these data indicate that the majority of leaf flavan-3-ols in Shuchazao’s leaves were produced from the ANR pathway.

One new and three known triterpenoid saponins were isolated and identified from Camellia oleifera seeds through IR, NMR, HR-ESI-MS and GC-MS spectroscopic methods, namely oleiferasaponin A3, oleiferasaponin A1, camelliasaponin B1, and camelliasaponin B2. The structure of oleiferasaponin A3 was elucidated as 16α-hydroxy-21β-O-angeloyl-22α-O-cinnamoyl-23α-aldehyde-28-dihydroxymethylene-olean-12-ene-3β-O-[β-d-galactopyranosyl-(1→2)]-[β-d-xylopyranosyl-(1→2)-β-d-galactopyranosyl-(1→3)]-β-d-gluco-pyranosiduronic acid. Camelliasaponin B1 and camelliasaponin B2 exhibited potent cytotoxic activity on three human tumour cell lines (human lung tumour cells (A549), human liver tumour cells (HepG2), cervical tumour cells (Hela)). The hypoglycemic activity of oleiferasaponin A1 was testified by protecting pancreatic β-cell lines from high-glucose damage.

The effects of different treatment methods on the stability and antioxidant capacity of the bioactive phenolic compounds of litchi pericarps were investigated. Fresh litchi pericarps were open air–dried, steam-blanched for 3 min in combination with hot air oven drying at 60 and 80 °C, and unblanched pericarps were dried in a hot air oven at 40, 60, 70 and 80 °C until equilibrium weight was reached. The total phenolic compounds, flavonoids, anthocyanins, proanthocyanidins and individual procyanidins, and antioxidant activity were analyzed. The combination of blanching and drying at 60 °C significantly (p < 0.05) improved the release of phenolic compounds, individual procyanidins, and the extracts′ antioxidant capacity compared with the unblanched hot air oven-dried and open air–dried pericarps. Drying of fresh unblanched litchi pericarps in either open air or a hot air oven caused significant losses (p < 0.05) in phenolic compounds and individual procyanidins, leading to a reduction in the antioxidant activity. A similar increase, retention or reduction was reflected in flavonoids, proanthocyanidins and anthocyanins because they are sub-groups of phenolic compounds. Ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryldydrazyl (DPPH) radical-scavenging capacity of the treated pericarps were significantly correlated (r ≥ 0.927, p < 0.01) with the total phenolic compounds. Thus, the combination of steam blanching and drying treatments of fresh litchi pericarps could produce a stable and dry litchi pericarp that maintains phenolic compounds and antioxidant capacity as a raw material for further recovery of the phytochemicals.

The effects of different treatment methods on the stability and antioxidant capacity of the bioactive phenolic compounds of litchi pericarps were investigated. Fresh litchi pericarps were open air-dried, steam-blanched for 3 min in combination with hot air oven drying at 60 and 80 °C, and unblanched pericarps were dried in a hot air oven at 40, 60, 70 and 80 °C until equilibrium weight was reached. The total phenolic compounds, flavonoids, anthocyanins, proanthocyanidins and individual procyanidins, and antioxidant activity were analyzed. The combination of blanching and drying at 60 °C significantly (p < 0.05) improved the release of phenolic compounds, individual procyanidins, and the extracts1 antioxidant capacity compared with the unblanched hot air oven-dried and open air-dried pericarps. Drying of fresh unblanched litchi pericarps in either open air or a hot air oven caused significant losses (p < 0.05) in phenolic compounds and individual procyanidins, leading to a reduction in the antioxidant activity. A similar increase, retention or reduction was reflected in flavonoids, proanthocyanidins and anthocyanins because they are sub-groups of phenolic compounds. Ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryldydrazyl (DPPH) radical-scavenging capacity of the treated pericarps were significantly correlated (r ⩾ 0.927, p < 0.01) with the total phenolic compounds. Thus, the combination of steam blanching and drying treatments of fresh litchi pericarps could produce a stable and dry litchi pericarp that maintains phenolic compounds and antioxidant capacity as a raw material for further recovery of the phytochemicals. [ABSTRACT FROM AUTHOR]

The effect of curing agent (6610) content and temperature on the rheological behavior of the epoxy resin CYD-128 was studied by DSC analysis and viscosity experiments. The results show that the resin system meets the requirements of processing technology. A complete reaction occurs when the curing agent content (40 parts per hundred resin, phr) is a little higher than the theoretical value (33.33 phr), while the degree of reaction of the resin system is reduced when the curing agent content is lower (25.00 phr) than theoretical value. However, excessive curing agent (50.00 phr) results in a lower reaction rate. Curing agent content has little influence on gel time when curing agent content exceeded 33.33 phr and the temperature was less than 70 °C. The isothermal viscosity-time curves shift towards the -x axis when the temperature rises from 50 °C to 80 °C. Meanwhile, higher temperature results in higher reaction rates. [ABSTRACT FROM AUTHOR]

Mangrove Streptomyces represent a rich source of novel bioactive compounds in medicinal research. A novel alkaloid, named 1-N-methyl-3-methylamino-[N-butanoic acid- 3′-(9′-methyl-8′-propen-7′-one)-amide]-benzo[f][1,7]naphthyridine-2-one (1) was isolated from Streptomyces albogriseolus originating from mangrove sediments. The structure of compound 1 was elucidated by extensive spectroscopic data analyses and verified by the 13C-NMR calculation at the B3LYP/6-311+G(2d,p) level of theory. [ABSTRACT FROM AUTHOR]