Edible chitosan-based Pickering emulsion coatings: Preparation, characteristics, and application in strawberry preservation.

The long-term application of plant essential oils in food preservation coatings is limited by their poor water solubility and high volatility, despite their recognized synergistic antimicrobial effects in postharvest fruit preservation. To overcome these limitations, a Pickering emulsion loaded with thyme essential oil (TEO) was developed by utilizing hydrogen bonding and electrostatic interactions to induce cross-linking of chitosan particles. This novel emulsion was subsequently applied in the postharvest storage of strawberries. The shear-thinning behavior (flow index <1) and elastic gel-like characteristics of the emulsion made it highly suitable for spray application. Regarding TEO release, the headspace concentration of TEO increased from 0.21 g/L for pure TEO to 1.86 g/L after two instances of gas release due to the stabilizing effect of the chitosan particles at the oil-water interface. Notably, no phase separation was observed during the 10-day storage of the emulsion. Consequently, the emulsion was successfully employed for the postharvest storage of strawberries, effectively preventing undesirable phenomena such as weight loss, a decrease in firmness, an increase in pH, and microbial growth. In conclusion, the developed Pickering emulsion coating exhibits significant potential for fruit preservation applications, particularly for extending the shelf life of strawberries.

Effect of different iron ratios on interaction and thermodynamic stability of bound whey protein isolate.

Whey protein isolates (WPI) are known to have mineral-binding capacity to promote iron absorption. The aim of this study was to investigate the effect of iron ratio on the conformational structure of iron-bound whey protein isolate (WPI-Fe) and its thermodynamic stability. It was shown that the iron to protein ratio affects both the iron binding capacity of WPI and the iron valence state on the surface of WPI-Fe complexes. As the iron content increases, aggregation between protein molecules occurs. In addition, WPI-Fe nanoparticles have thermodynamic stability and Fe2+ has a high affinity with WPI for spontaneous exothermic reactions. This study demonstrates that WPI-Fe complexes can be used to efficiently deliver high-quality iron source (Fe2+) for future iron supplements.

Methyl jasmonate regulation of pectin polysaccharides in Cosmos bipinnatus roots: A mechanistic insight into alleviating cadmium toxicity.

Methyl jasmonate (MeJA), a crucial phytohormone, which plays an important role in resistance to Cadmium (Cd) stress. The cell wall (CW) of root system is the main location of Cd and plays a key role in resistance to Cd toxicity. However, the mechanism effect of MeJA on the CW composition and Cd accumulation remain unclear. In this study, the contribution of MeJA in regulating CW structure, pectin composition and Cd accumulation was investigated in Cosmos bipinnatus. Phenotypic results affirm MeJA's significant role in reducing Cd-induced toxicity in C. bipinnatus. Notably, MeJA exerts a dual impact, reducing Cd uptake in roots while increasing Cd accumulation in the CW, particularly bound to pectin. The molecular structure of pectin, mainly uronic acid (UA), correlates positively with Cd content, consistent in HC1 and cellulose, emphasizing UA as pivotal for Cd binding. Furthermore, MeJA modulates pectin methylesterase (PME) activity under Cd stress, influencing pectin's molecular structure and homogalacturonan (HG) content affecting Cd-binding capacity. Chelate-soluble pectin (CSP) within soluble pectins accumulates a substantial Cd proportion, with MeJA regulating both UA content and the minor component 3-deoxy-oct-2-ulosonic acid (Kdo) in CSP. The study delves into the intricate regulation of pectin monosaccharide composition under Cd stress, revealing insights into the CW's physical defense and Cd binding. In summary, this research provides novel insights into MeJA-specific mechanisms alleviating Cd toxicity in C. bipinnatus, shedding light on complex interactions between MeJA, and Cd accumulation in CW pectin polysaccharide.

Reducing sweetness expectation in milk tea by crossmodal visuo-auditory interaction.

In the realm of healthy dietary choices about reducing sweetness perception, the exploration of crossmodal effects stands as a frequently employed approach. Both music and color can independently influence flavor evaluation and gustatory experience by eliciting emotions. However, less research has been done on the effects of audio-visual crossmodal interactions on sweetness expectations and perceptions. The present study conducted two experiments delving into the crossmodal effect on sweetness expectation and perception of milk tea by manipulating the emotional valence of music and packaging color. The results showed that positive (vs. negative) music led to higher sweetness expectations and perceptions for milk teas with neutral packaging color. Irrespective of music, participants had higher sweetness expectations for milk tea with positive or neutral (vs. negative) packaging colors. The congruence of valence between music and packaging color influenced sweetness perception. Positive (vs. negative) music correlated with a sweeter perception when the packaging color was positive. Exposed to negative music, subjects showed a higher sweetness perception with negative (vs. positive) packaging colors. In conclusion, the results suggest that the valence of music and packaging color crossmodally influence consumers' evaluation of milk tea, and it differs depending on whether it was tasted. Thus, this study has demonstrated the crossmodal influence of music and packaging color, providing valuable implications for healthy eating and marketing applications.

Fermentation of Ganoderma lucidum and Raphani Semen with a probiotic mixture attenuates cyclophosphamide-induced immunosuppression through microbiota-dependent or -independent regulation of intestinal mucosal barrier and immune responses.

BACKGROUND: Probiotic fermentation is a promising strategy for improving the nutritional and functional properties of traditional Chinese medicines (TCMs). Ganoderma lucidum and Raphani Semen are famous TCMs that have been shown to help alleviate immune system disorders. However, few studies have experimentally investigated the effects of probiotic-fermented G.lucidum and Raphani Semen on the immune system. PURPOSE: We established the in vitro fermentation of G. lucidum and Raphani Semen with a probiotic mixture (Bifidobacterium longum, Lactobacillus acidophilus, and l. fermentum) (GRFB), investigated its ameliorating effect against cyclophosphamide (CTX)-induced immunosuppression, and explored its possible mechanisms. METHODS: First, the different components in GRFB were identified by high-performance liquid chromatography. Second, its immune-stimulatory activities were evaluated in CTX-treated mice. Lastly, its possible in vitro and in vivo mechanisms were studied. RESULTS: Probiotic fermentation of G. lucidum and Raphani Semen altered some of its chemical constituents, potentially helping improve the ability of GRFB to alleviate immunosuppression. As expected, GRFB effectively ameliorated CTX-induced immunosuppression by increasing the number of splenic lymphocytes and regulating the secretion of serum and ileum cytokines. GRFB supplementation also effectively improved intestinal integrity in CTX-treated mice by upregulating tight junction proteins. It also protects against CTX-induced intestinal dysbiosis by increasing the abundance of beneficial bacteria and reducing the abundance of harmful bacteria. GRFB could directly promote intestinal immunity but not systemic immunity in vitro, suggesting a microbiota-dependent regulation of GRFB. Interestingly, cohousing CTX-induced immunosuppressed mice with GRFB-treated mice promoted their symptoms recovery. Enhanced CTX-induced immunosuppression by GRFB in vitro depended on the gut microbiota. Remarkably, a Kyoto Encyclopedia of Genes and Genomes analysis showed that the GRFB-reprogrammed microbiota was significantly enriched in DNA damage repair pathways, which contribute to repairing the intestinal mucosal barrier. CONCLUSION: This is the first study to suggest that compare with unfermented G. lucidum and Raphani Semen, GRFB can more effectively promote intestinal immunity and manipulate the gut microbiota to promote immunostimulatory activity and repair immunosuppression-induced intestinal barrier damage by biotransforming G.lucidum and Raphani Semen components.

Filamentous Fungi-Derived Orsellinic Acid-Sesquiterpene Meroterpenoids: Fungal Sources, Chemical Structures, Bioactivities, and Biosynthesis.

Fungi-derived polyketide-terpenoid hybrids are important meroterpenoid natural products that possess diverse structure scaffolds with a broad spectrum of bioactivities. Herein, we focus on an ever-increasing group of meroterpenoids, orsellinic acid-sesquiterpene hybrids comprised of biosynthetic start unit orsellinic acid coupling to a farnesyl group or/and its modified cyclic products. The review entails the search of China National Knowledge Infrastructure (CNKI), Web of Science, Science Direct, Google Scholar, and PubMed databases up to June 2022. The key terms include "orsellinic acid", "sesquiterpene", "ascochlorin", "ascofuranone", and "Ascochyta viciae", which are combined with the structures of "ascochlorin" and "ascofuranone" drawn by the Reaxys and Scifinder databases. In our search, these orsellinic acid-sesquiterpene hybrids are mainly produced by filamentous fungi. Ascochlorin was the first compound reported in 1968 and isolated from filamentous fungus Ascochyta viciae (synonym: Acremonium egyptiacum; Acremonium sclerotigenum); to date, 71 molecules are discovered from various filamentous fungi inhabiting in a variety of ecological niches. As typical representatives of the hybrid molecules, the biosynthetic pathway of ascofuranone and ascochlorin are discussed. The group of meroterpenoid hybrids exhibits a broad arrange of bioactivities, as highlighted by targeting hDHODH (human dihydroorotate dehydrogenase) inhibition, antitrypanosomal, and antimicrobial activities. This review summarizes the findings related to the structures, fungal sources, bioactivities, and their biosynthesis from 1968 to June 2022.

The interaction study of soluble pectin fiber and surimi protein network from silver carp (Hypophthalmichthys molitrix) based on a new prediction model.

Pure surimi of silver carp (Hypophthalmichthys molitrix) cannot meet the texture requirements in novel 3D printing of food. In this work, the effect mechanism of adding soluble pectin fiber on the quality of surimi was studied at molecular scale, and the interaction has been discussed by a novel prediction model. In comparison with pure surimi, pH and water-holding capacity decreased with increasing pectin, and texture properties improved. The storage modulus firstly rose and then decreased, reaching a maximum value of 15012 Pa at 0.5 % pectin addition. The thermal transition temperature of myosin was moved from 52.13 to 49.80 °C. Pectin extended the T22 relaxation time, suggesting a decrease in immobilized water. A new Time-series prediction model and interaction analysis further explored the intrinsic correlation of various parameters of surimi with different pectin additions. This work contributes to add our understanding of pectin application in surimi products in future special dietary food.

Ultrasound-alkaline combined extraction improves the release of bound polyphenols from pitahaya (Hylocereus undatus 'Foo-Lon') peel: Composition, antioxidant activities and enzyme inhibitory activity.

In this study, ultrasound-assisted alkaline hydrolysis was used to extract polyphenols from pitahaya peel. The effects of sonication time, ultrasonic density, NaOH concentration and the liquid-material ratio on the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the extracts were studied. The composition and content difference of the extracts were analyzed and the inhibitory effect of α-amylase and α-glucosidase was measured. The results of single-factor analysis showed that when the sonication time was 45 min, the ultrasonic density was 32 W/L, the NaOH solution concentration was 6 M and the liquid-material ratio was 30 mL/g, the release of phenolic compounds was the largest and the antioxidant activity was the strongest. An UPLC-QTOF-MS/MS method was used to analyze the components and contents of the extracts. We found that there was a great difference in the component content of the free polyphenol extract and the bound polyphenol extract. From the results, we concluded that there was a strong correlation between the type and content of phenolic compounds and antioxidant activities, indicating that phenolic compounds were the main compounds of these biological activities. Moreover, the bound polyphenol extracts showed a significant inhibitory effect on α-amylase and α-glucosidase was stronger than that of the free polyphenol extracts. In addition, scanning electron microscopy showed that ultrasound-assisted extraction is crucial to the destruction of the cell wall and the release of bound polyphenols. Therefore, the pitahaya peel has the potential for therapeutic, nutritional, and functional food applications, and ultrasound-assisted alkaline hydrolysis is an effective means to release phenolic compounds.

A New Gold Nanoparticles and Paclitaxel Co-Delivery System for Enhanced Anti-Cancer Effect Through Chemo-Photothermal Combination.

Limited chemotherapeutic efficiency, drug resistance and side effect are primary obstacles for cancer treatment. The development of co-delivery system with synergistic treatment modes should be a promising strategy. Here, we fabricated a multi-functionalized nanocarrier with a combination of chemotherapeutic agent and gold nanoparticles (AuNPs), which could integrate chemo-photothermal therapy and improve entire anti-cancer index. Particularly, Paclitaxel nanocrystals (PTX NC) were first fabricated as a platform, on surface of which AuNPs were decorated and polydopamine (PDA) layer act as capping, stabilizing and hydrophilic agents for PTX NC, providing a bridge connecting AuNPs to PTX. These AuNPs decorated PTX NC exhibited good physico-chemical properties like optimal sizes, stability and photothermal efficiency. Compared to other PTX formulations, they displayed considerably improved biocompatibility, selectivity, intracellular uptake, cytotoxicity, apoptosis induction activity and P-glycoprotein (Pgp) inhibitory capability, owing to a synergistic/ cooperative effect from AuNPs, PTX and NIR treatment, photothermal-triggered drug release and nano-scaled structure. Mitochondria-mediated signaling pathway is underlying mechanism for cytotoxic and apoptotic effect from AuNPs decorated PTX NC, in terms of Mitochondria damage, a loss of Mitochondrial membrane potential, intensified oxidative stress, DNA breakage, Caspase 3 activation, up-regulated expression in pro-apoptotic genes like p53, Caspase 3 and Bax and down-regulated level in anti-apoptotic gene like Bcl-2.

Total flavones from Sceptridium ternatum alleviate pulmonary hypertension through inhibiting the proliferation of vascular endothelial cells.

Background: Sceptridium ternatum is a traditional Chinese medicine that is prescribed to treat respiratory diseases in China. Our previous study confirmed that total flavones from Sceptridium ternatum (FST) have preventive and therapeutic effects on pulmonary hypertension (PH). The present study sought to investigate the mechanism underpinning the therapeutic efficacy of FST in PH. Methods: Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays, real-time quantitative PCR (RT-qPCR), western blot, flow cytometry, high-throughput sequencing, and bioinformatics analysis were performed to study the therapeutic mechanism of FST in PH at the gene, cell, and animal levels. Results: The results showed that FST could inhibit the proliferation of both human pulmonary artery smooth muscle cells (HPASMCs) and human pulmonary microvascular endothelial cells (HPMECs), and downregulate the expression of HIF1α and HIF2α, which are the key factors in the pathogenesis and occurrence of PH. FST could also inhibit the activation of the downstream JAK2-STAT3 signaling pathway and upregulate the expression of the negative regulator SOCS1. Vascular endothelial cell and smooth muscle cell proliferation was inhibited and the symptoms of PH were relieved by FST. Conclusions: The findings of this study offer important clues for the identification of new molecular targets in FST treatment and the development of treatment strategies for PH.

Mapping the research hotspots and theme trends of simulation in nursing education: A bibliometric analysis from 2005 to 2019.

BACKGROUND: Simulation-based nursing training has been used incorporated into nursing education for decades, however, there is limited information related to simulation research hotspots and theme trends over time. OBJECTIVES: To investigate the research hotspots and theme trends of simulation in nursing education through bibliometric analysis. METHODS: Relevant articles on simulation in nursing education published between 2005 and 2019 were retrieved from PubMed. The Bibliographic Item Co-occurrence Matrix Builder (BICOMB) was used to extract and quantitatively analyze the Medical Subject Headings (MeSH) terms and subheadings. The biclustering analysis was conducted using gCluto1.0 to identify the research hotspots. A strategic diagram was employed to reveal the development trend of the theme. RESULTS: A total of 4102 publications were retrieved from PubMed showing an overall increasing trend. Based on the results, the United States was the most productive country (2868,55.7 %), the journal Nurse Education Today journal was the top journal concerning this field, and Cooper SJ and Holtschneider ME were authors with the highest number of publications on this topic. Quantitative and co-word biclustering analyses were used in this study. The research hotspots in recent 5 years were focused on: (1) interprofessional simulation in patient-care teams; (2) patient simulation in psychiatric nursing education; (3) virtual reality simulation (VRS) in midwifery and nursing education; (4) simulation in critical care nurses' continuing education/training, and (5) simulation in pediatric resuscitation education. The strategic diagram showed that the VRS in midwifery and nursing education might have a significant potential to become an emerging hotspot soon. CONCLUSION: The research literature production of simulation in nursing education was increasing over the past 15 years. Through co-word biclustering analysis, five research hotspots were identified. Among them, simulation in psychiatric education and critical care continuing education had a central priority that researchers should pay further attention to, and VRS could be the major trend for future study. Furthermore, this study described the overall range of research interests and provided ideas for innovative and efficient research projects.

Efficacy of Qingfei oral liquid for idiopathic pulmonary fibrosis in rats and related network pharmacology study.

To investigate the therapeutic effect and mechanism of Qingfei oral liquid in idiopathic pulmonary fibrosis. Seventy-two male SD rats were divided into control group, model group, pirofenidone group and Qingfei group with 18 animals in each group. The idiopathic pulmonary fibrosis was induced in last three groups by intratracheal injection of bleomycin; pirofenidone group was given oral administration of pirofenidone b.i.d for 21 d, and Qingfei group was given Qingfei oral liquid 3.6 mL/kg q.d for Lung tissues were obtained for HE staining, Masson staining and transforming growth factor (TGF)-ß immunohistochemical staining. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were detected in tissue homogenates. The BATMAN-TCM database was used to retrieve the chemical components and their corresponding targets of Qingfei oral solution by network pharmacology method, and then the component-target-disease network diagram was constructed. Finally, the pathway enrichment analysis was carried out to explore the molecular mechanism of Qingfei oral liquid against idiopathic fibrosis. Histopathology results showed that Qingfei oral liquid had a similar relieving effect on pulmonary fibrosis as the positive drug pirfenidone; TGF-ß secretion had a significant reduction in lung tissues of Qingfei group; and Qingfei oral liquid had better regulatory effect on SOD, MDA and GSH than pirfenidone. The results of component-target-disease network and pathway enrichment analysis showed that the related molecular pathways were concentrated in inflammation, extracellular matrix and cytokines. Qingfei oral liquid has a good therapeutic effect on idiopathic pulmonary fibrosis in rats via regulation of inflammation, extracellular matrix and cytokines.

Gold Nanoparticle-Decorated Drug Nanocrystals for Enhancing Anticancer Efficacy and Reversing Drug Resistance Through Chemo-/Photothermal Therapy.

Limited chemotherapeutic efficiency, drug resistance, and side effects are primary obstacles for cancer treatment. The development of co-delivery systems with synergistic treatment modes should be a promising strategy. Here, we fabricated a multifunctionalized nanocarrier with a combination of chemotherapeutic agents and gold nanoparticles (AuNPs), which could integrate chemo-photothermal therapy, thus enhancing overall anticancer efficacy, sensitizing drug-resistant cancer cells, and diminishing cancer stem cells (CSCs). To be specific, camptothecin nanocrystals (CPT NCs) were prepared as a platform, on the surface of which AuNPs were decorated and a hyaluronic acid layer acted as capping, stabilizing, targeting, and hydrophilic agents for CPT NCs, and reducing agents for AuNPs, providing a bridge connecting AuNPs to CPT. These AuNP-decorated CPT NCs exhibited good physico-chemical properties such as optimal sizes, payload, stability, and photothermal efficiency. Compared to other CPT formulations, they displayed considerably improved biocompatibility, selectivity, intracellular uptake, cytotoxicity, apoptosis induction activity, Pgp inhibitory capability, and anti-CSC activity, owing to a synergistic/cooperative effect from AuNPs, CPT, near-infrared treatment, pH/photothermal-triggered drug release, and nanoscaled structure. A mitochondrial-mediated signaling pathway is the underlying mechanism for cytotoxic and apoptotic effects from AuNP-decorated CPT NCs, in terms of mitochondrial dysfunction, intensified oxidative stress, DNA fragmentation, caspase 3 activation, upregulation of proapoptotic genes such as p53, Bax, and caspase 3, and lower levels of antiapoptotic Bcl-2.

Botrychium schaffneri Underw. extract acts via DIABLO to induce apoptosis and inhibit proliferation of non-small cell lung carcinoma in vitro and in vivo.

BACKGROUND: Botrychium schaffneri Underw. has been popularly consumed since ancient times as a traditional medicine in China to treat whooping cough, bronchial asthma, and febrile convulsive twitch disease. This led us to investigate whether Botrychium schaffneri Underw. extract (BSE) may be effective against lung cancer, especially non-small cell lung carcinoma (NSCLC). METHODS: In this study, we extracted the ethanolic root extract of the grass, Botrychium schaffneri Underw. In vitro study, the change of NCI-H1299 cell proliferation was observed with CCK8 and MTT assays. Cell apoptosis was assessed using a kit based on staining with FITC-conjugated annexin V. In vivo study, we establish a stable animal model of NSCLC in nude mice, tumor volume and weight was measured twice a week. We conduct gene microarray screened for differentially expressed genes (DEGs), between NCI-H1299 cells treated by BSE or not. Then the DEGs were functionally annotated and path enriched. RESULTS: It was revealed that BSE significantly suppressed NSCLC cell proliferation (IC50 134 µg/mL) and induced apoptosis. It also slowed tumor growth without affecting body weight, and a dose of 25 g/kg led to significantly smaller tumors than in control animals (13.85±3.36 vs. 23.40±6.05, P=0.044). Apoptosis-related protein direct IAP Binding protein with low PI (DIABLO) expression was up-regulated by BSE, and DIABLO knockdown significantly attenuated the anti-tumor effects of the extract. CONCLUSIONS: In conclusion, BSE reduces the viability of NSCLC cells and promotes apoptosis, and these effects may be mediated by DIABLO.

Mowing enhances the phytoremediation ability of cadmium-contaminated soil in the post-grafting generations of potential cadmium-hyperaccumulator Solanum photeinocarpum.

The study aimed at accessing the effects of mowing on the growth and cadmium (Cd) accumulation of the first post-grafting generation of potential Cd-hyperaccumulator plant Solanum photeinocarpum through the pot and plot experiments. Four grafting treatments were employed such as ungrafted (UG), self-rooted grafting by the same S. photeinocarpum seedling (SG), self-rooted grafting by two different development stages of S. photeinocarpum seedlings (DG), and grafting on the rootstock of wild potato (PG). The biomass, Cd content, and Cd extraction amount of S. photeinocarpum shoots significantly decreased with the increase of mowing times in the pot and plot experiments. The order of the grafting on the biomass, Cd content, and Cd extraction amountof in the first, second, third mowing shoots were PG > DG > SG > UG. For the Cd extraction amountof total moving shoots, SG, DG, and PG increased by 20.42%, 35.54%, and 52.94%, respectively, in the pot experiment, and increased by 11.56%, 26.28%, and 44.90%, respectively, in the plot experiment, compared with the UG. Therefore, mowing provides an insight into the phytoremediation ability of S. photeinocarpum to Cd.

Hyaluronic Acid-Coated Camptothecin Nanocrystals for Targeted Drug Delivery to Enhance Anticancer Efficacy.

Tumor-targeted drug delivery via chemotherapy is very effective on cancer treatment. For potential anticancer agent such as Camptothecin (CPT), high chemotherapeutic efficacy and accurate tumor targeting are equally crucial. Inspired by special CD44 binding capability from hyaluronic acid (HA), in this study, novel HA-coated CPT nanocrystals were successfully prepared by an antisolvent precipitation method for tumor-targeted delivery of hydrophobic drug CPT. These HA-coated CPT nanocrystals demonstrated high drug loading efficiency, improved aqueous dispersion, prolonged circulation, and enhanced stability resulting from their nanoscaled sizes and hydrophilic HA layer. Moreover, as compared to crude CPT and naked CPT nanocrystals, HA-coated CPT nanocrystals displayed dramatically enhanced in vitro anticancer activity, apoptosis-inducing potency against CD44 overexpressed cancer cells, and lower toxic effect toward normal cells due to pH-responsive drug release behavior and specific HA-CD44 mediated endocytosis. Additionally, HA-coated CPT nanocrystals performed fairly better antimigration activity and biocompatibility. The possible molecular mechanism regarding this novel drug formulation might be linked to intrinsic mitochondria-mediated apoptosis by an increase of Bax to Bcl-2 ratio and upregulation of P53. Consequently, HA-coated CPT nanocrystals are expected to be an effective nanoplatform in drug delivery for cancer therapy.

Comparison of the adsorption behaviour of catechin onto cellulose and pectin.

The adsorption behaviour of catechin onto cellulose and pectin was compared. The adsorption of catechin onto the two fibres involved an initial fast adsorption phase followed by a slower adsorption as the sites became saturated and the systems moved towards equilibrium. The adsorption capacity of pectin for catechin (20.71 ±â€¯2.24 mg/g) was significantly greater than that of cellulose (2.41 ±â€¯0.05 mg/g) after equilibration for 24 h at 37 °C. The Langmuir and Freundlich models were applied to obtain the quantitative information about the adsorption of catechins to pectin and cellulose. Thermodynamic data derived from the isothermal adsorption carried out at the temperatures of 27 °C, 32 °C, 37 °C and 42 °C suggested that the adsorption was spontaneous and the binding was driven predominantly by physisorption. Fluorescence experiments confirmed the adsorption of catechins onto cellulose and pectin. The results showed that catechin adsorption capacity and adsorption mechanism were different for pectin and cellulose.

Functional characterization of squalene epoxidase genes in the medicinal plant Tripterygium wilfordii.

Squalene epoxidase, thought to be one of the rate-limiting enzymes in the biosynthetic pathways of both membrane sterols and triterpenes (e.g., celastrol), catalyses the formation of oxidosqualene as the common precursor of sterols and triterpenoids. In this work, we first found five squalene epoxidase genes (TwSEs) from Tripterygium wilfordii. Tissue expression pattern, consistent with methyl jasmonate induction study, showed that TwSEs1-4 were involved in the production of special metabolites. In contrast, TwSE5 showed a different tissue expression pattern and was not induced by methyl jasmonate. To probe the functions of the TwSEs, we first tried using a prokaryotic system by constructing an engineered bacterium, but we failed to detect their products. Next, we used the CRISPR/Cas9 tool to construct an erg1 mutant yeast by knocking out the ERG1 gene of yeast strain BY4741 and then applied this mutant to identify the function of TwSEs. We found that only TwSEs1-4 can functionally complement the erg1 mutant yeast. This study laid the foundation for the heterologous biosynthesis of special metabolites in Tripterygium wilfordii.

Lycii fructus extract ameliorates hydrogen peroxide-induced cytotoxicity through indirect antioxidant action.

Lycii Fructus is the dried ripe fruits of Lycium chinense and L. barbarum, which has long been used as a traditional food material in East Asia. The purpose of this study was to investigate the role of the indirect antioxidative action in the Lycii fructus extract (LFE)-induced cytoprotective effect in vitro. LFE significantly enhanced the expression of the drug-metabolizing enzyme genes and intracellular glutathione level in mouse hepatoma Hepa1c1c7 cells. LFE stimulated the nuclear translocation of aryl hydrocarbon receptor as well as nuclear factor (erythroid-derived 2)-like 2. The pretreatment of LFE for 24 h, but not for 30 min, completely inhibited the cytotoxic effect of hydrogen peroxide. Furthermore, chlorogenic acid, one of the main constituents of LFE, showed cytoprotection against hydrogen peroxide with the enhanced phase 2 enzyme gene expression. These results suggested that LFE exhibits a cytoprotective effect, possibly through the enhancement of the antioxidant gene expression. ABBREVIATIONS: LFE: Lycii Fructus extract; GSH: glutathione; NQO1: NAD(P)H:quinone oxidoreductase 1; HO-1: heme oxygenase-1; GCLC: glutamate-cysteine ligase, catalytic subunit; xCT: a component of cysteine/glutamate antiporter (cystine/glutamate exchanger); CYP1A1: cytochrome P450 1A1; GSH: glutathione; AhR: aryl hydrocarbon receptor; Nrf2: nuclear factor (erythroid-derived 2)-like 2; CGA: chlorogenic acid; RT-PCR: reverse transcription-polymerase chain reaction; DTT: dithiothreitol; PMSF: phenylmethylsulfonyl fluoride; ARE: antioxidant response element; XRE: xenobiotic responsive element.

Identification and functional characterization of diterpene synthases for triptolide biosynthesis from Tripterygium wilfordii.

Tripterygium wilfordii, which has long been used as a medicinal plant, exhibits impressive and effective anti-inflammatory, immunosuppressive and anti-tumor activities. The main active ingredients are diterpenoids and triterpenoids, such as triptolide and celastrol, respectively. A major challenge to harnessing these natural products is that they are found in very low amounts in planta. Access has been further limited by the lack of knowledge regarding their underlying biosynthetic pathways, particularly for the abeo-abietane tri-epoxide lactone triptolide. Here suspension cell cultures of T. wilfordii were found to produce triptolide in an inducible fashion, with feeding studies indicating that miltiradiene is the relevant abietane olefin precursor. Subsequently, transcriptome data were used to identify eight putative (di)terpene synthases that were then characterized for their potential involvement in triptolide biosynthesis. This included not only biochemical studies which revealed the expected presence of class II diterpene cyclases that produce the intermediate copalyl diphosphate (CPP), along with the more surprising finding of an atypical class I (di)terpene synthase that acts on CPP to produce the abietane olefin miltiradiene, but also their subcellular localization and, critically, genetic analysis. In particular, RNA interference targeting either both of the CPP synthases, TwTPS7v2 and TwTPS9v2, or the subsequently acting miltiradiene synthase, TwTPS27v2, led to decreased production of triptolide. Importantly, these results then both confirm that miltiradiene is the relevant precursor and the relevance of the identified diterpene synthases, enabling future studies of the biosynthesis of this important bioactive natural product.