Fast Screening of Tyrosinase Inhibitors in Coreopsis tinctoria Nutt. by Ligand Fishing Based on Paper-Immobilized Tyrosinase.

Coreopsis tinctoria Nutt. is an important medicinal plant in traditional Uyghur medicine. The skin-lightening potential of the flower has been recognized recently; however, the active compounds responsible for that are not clear. In this work, tyrosinase, a target protein for regulating melanin synthesis, was immobilized on the Whatman paper for the first time to screen skin-lightening compounds present in the flower. Quercetagetin-7-O-glucoside (1), marein (2), and okanin (3) were found to be the enzyme inhibitors. The IC50 values of quercetagetin-7-O-glucoside (1) and okanin (3) were 79.06 ± 1.08 µM and 30.25 ± 1.11 µM, respectively, which is smaller than 100.21 ± 0.11 µM of the positive control kojic acid. Enzyme kinetic analysis and molecular docking were carried out to investigate their inhibition mechanism. Although marein (2) showed a weak inhibition effect in vitro, it inhibited the intracellular tyrosinase activity and diminished melanin production in melanoma B16 cells as did the other two inhibitors. The paper-based ligand fishing method developed in this work makes it effective to quickly screen tyrosinase inhibitors from natural products. This is the first report on the tyrosinase inhibitory effect of those three compounds, showing the promising potential of Coreopsis tinctoria for the development of herbal skin-lightening products.

Optimizing Coreopsis tinctoria Flower Extraction and Inhibiting CML Activity: Box-Behnken Design.

BACKGROUND: Chronic myelogenous leukemia (CML) is an uncommon type of cancer of the bone marrow associated with high mortality. Although several effective therapies have been developed to reduce symptoms in patients with CML, many of these methods are associated with side effects. Coreopsis tinctoria Nutt. (C. tinctoria) is a natural medicinal material that possesses antioxidant and anticancer activities. Yet, its effect in treating leukemia has still not been fully explored. OBJECTIVE: To optimize the C. tinctoria flower extraction process and investigate whether these extracts can impair CML cell survival. METHODS: The extraction process of C. tinctoria was optimized by the Box-Behnken design response surface method. K562 cells were treated with different volumes (0, 10, 25, 50, and 100 µL) of C. tinctoria flower extracts. The effect of C. tinctoria extract on cell morphology and cell apoptosis was assessed by light microscopy, laser confocal microscopy, and flow cytometry. RESULTS: We established the following optimized C. tinctoria flower extraction conditions: temperature of 84.4°C, extraction period of 10 mins, solid-liquid ratio of 1:65, and times 4. These conditions were applied for C. tinctoria flower extraction. Pre-incubation of extracts prepared under the aforementioned optimal conditions with K562 cells induced cell cytotoxicity and cell apoptosis. CONCLUSION: C. tinctoria flower extracts exert obvious anti-leukemia effects in vitro and may be a potential drug candidate for leukemia treatment.

Development of an LC/MS/MS Method for Simultaneous Detection of 11 Polyphenols in Rat Plasma and Its Pharmacokinetic Application after Oral Administration of Coreopsis tinctoria Extract.

Eleven polyphenols, classified as flavonoid glycosides, flavonoid aglycones, and phenolic acids, are important bioactive components in the capitula of Coreopsis tinctoria (CCT). Nevertheless, their full pharmacokinetic profiles have not been demonstrated simultaneously. Therefore, a liquid chromatography - tandem mass spectrometry (LC/MS/MS) method was developed in the present work and used it to study the pharmacokinetics of these 11 compounds. We performed LC/MS/MS with a gradient mobile phase composed of water containing 0.1 % formic acid and acetonitrile containing 0.1 % formic acid on a Proshell 120 SB C18 column (2.1 mm×100 mm, 2.7 µm). We achieved a good chromatographic peak shape, resolution, and mass signal response, and multiple reaction monitoring facilitated the simultaneous detection of 11 analytes. In addition, we validated the selectivity, correlation coefficient, precision, extraction recovery, matrix effects, and stability of the LC/MS/MS method to be acceptable for 11 analytes in rat plasma. Subsequently, rats were orally administered with 50 % ethanol eluent of CCT (ECCT). Nine of 11 polyphenols were absorbed quickly (except for QCD and TCA), and their plasma levels peaked within 40 min. The exposure and Cmax values of flavonoid glycosides and phenolic acids were lower than those of flavonoid aglycones. This is the first report to demonstrate the pharmacokinetics of 11 polyphenols in ECCT, which may play an important role in future studies of the bioactive components of ECCT and their bioactive mechanisms.

Impact of Coreopsis tinctoria Nutt. Essential oil microcapsules on the formation of biogenic amines and quality of smoked horsemeat sausage during ripening.

The present study evaluated the effect of Coreopsis tinctoria Nutt. essential oil (CEO) and its microcapsules (CEOM) on the accumulation of biogenic amines (BAs) and the quality of smoked horsemeat sausage during fermentation. The results showed that CEO could effectively inhibit Enterobacteriaceae growth and the formation of BAs (cadaverine, putrescine, tyrosine, histamine and tryptamine) in smoked horsemeat sausages, and the inhibition of CEO was enhanced after embedding (P < 0.05). Compared with other groups, thiobarbituric acid reactive substances, total volatile basic nitrogen and pH were lower in the microcapsule group. Furthermore, the sensory evaluation indicated that the addition of CEOM was a more effective way to maintain color and delay the deterioration of the sensory quality of sausages. Therefore, it is suggested that the CEOM can be used as a natural preservative in traditional fermented meat products to inhibit BAs accumulation and improve quality.

Lanceolanone A, a new biflavanone, and a chalcone glucoside from the flower heads of Coreopsis lanceolata and their aldose reductase inhibitory activity and AMPK activation.

The MeOH extract of the flower heads of Coreopsis lanceolata L. (Asteraceae) exhibited aldose reductase (AR) inhibitory activity (IC50 8.36 µg/mL). Bioassay-guided fractionation of the extract resulted in the isolation of a new biflavanone-named Lanceolanone A (1) and a chalcone glucoside (6), along with 12 known compounds (2-5 and 7-14), of which 4, 7, 9, 10, and 12 were isolated from C. lanceolata for the first time. The structures of the new compounds (1 and 6) were determined by extensive spectroscopic analysis, including two-dimensional (2D) NMR, and ECD calculation method. Compounds 2, 4, 11, 13, and 14 exhibited AR inhibitory activities with IC50 values between 2.40 and 9.99 µM. Furthermore, 8-13 at 1.0 mM activated AMPK expression in HepG2 human hepatoma cells compared to the control.

Antioxidant properties of polyphenols from snow chrysanthemum (Coreopsis tinctoria) and the modulation on intestinal microflora in vitro.

CONTEXT: Coreopsis tinctoria Nutt (Asteraceae), named snow chrysanthemum, is known to have a high level of polyphenols. However, the potential prebiotic effect on modulating intestinal microflora is still unclear. OBJECTIVE: The chemical composition, antioxidant properties of snow chrysanthemum polyphenols (SCPs) and their effects on human intestinal microbiota were investigated. MATERIALS AND METHODS: SCPs were extracted using ultrasonic-assisted extraction, and further determined using UPLC-QE Orbitrap/MS. Five assays were used to investigate the antioxidant activities of SCPs. Subsequently, the effects of SCPs on intestinal microbiota in vitro were determined by high throughput sequencing and bioinformatics analysis. RESULTS: Marein, isookanin and cymaroside were the major phenolic compounds, which accounted for 42.17%, 19.53% and 12.25%, respectively. Marein exhibited higher scavenging capacities in DPPH (EC50 = 8.84 µg/mL) and super anion radical assay (EC50 = 282.1 µg/mL) compared to cymaroside and isookanin. The antioxidant capacity of cymaroside was weakest among the three phenolic compounds due to the highest EC50 values, especially for superoxide anion radical assay, EC50 > 800 µg/mL. The result of in vitro fermentation showed that the three phenolic compounds increased the relative abundances of Escherichia/Shigella, Enterococcus, Klebsiella, etc., and isookanin notably increased the relative abundance of Bifidobacterium and Lactobacillus. DISCUSSION AND CONCLUSIONS: SCPs exhibited antioxidant properties and potential prebiotic effects on modulating the gut microbiota composition. The findings indicated that SCPs consumption could exert prebiotic activity that is beneficial for human health.

Effect of Different Roasting Conditions and Coreopsis Extract on Heterocyclic Amine Formation in Roast Lamb Products.

ABSTRACT: Heterocyclic amines (HCAs), which are known carcinogens in thermally processed foods, were investigated in roast lamb patties under various time and temperature conditions. HCAs in lamb products roasted at some temperatures increased with roasting time. An exponential model with a time factor fit well for the production of HCAs. The mean pH and cooking loss at various temperatures were also determined. The mean pH decreased as the temperature increased. Coreopsis extract was added to lamb patties roasted at 230°C for 15 min per side. The amount of coreopsis extract added had a significant effect on HCA development. A weak positive relationship was observed between the antioxidant activity of the lamb patty with the coreopsis extract and the inhibitory effect of coreopsis extract on various HCAs, with a correlation coefficient of 0.14 to 0.44 (P > 0.05). Coreopsis extract containing flavonoids can be a beneficial additive for production of barbecue meat.

Physiological and rhizospheric response characteristics to cadmium of a newly identified cadmium accumulator Coreopsis grandiflora Hogg. (Asteraceae).

Screening for superior cadmium (Cd) phytoremediation resources and uncovering the mechanisms of plant response to Cd are important for effective phytoremediation of Cd-polluted soils. In this study, the characteristics of Coreopsis grandiflora related to Cd tolerance and accumulation were analyzed to evaluate its Cd phytoremediation potential. The results revealed that C. grandiflora can tolerate up to 20 mg kg-1 of Cd in the soil. This species showed relatively high shoot bioconcentration factors (1.09-1.85) and translocation factors (0.46-0.97) when grown in soils spiked with 5-45 mg kg-1 Cd, suggesting that C. grandiflora is a Cd accumulator and can potentially be used for Cd phytoextraction. Physiological analysis indicated that antioxidant enzymes (i.e., superoxide dismutase, peroxidase, and catalase) and various free amino acids (e.g., proline, histidine, and methionine) participate in Cd detoxification in C. grandiflora grown in soil spiked with 20 mg kg-1 of Cd (Cd20). The overall microbial richness and diversity remained similar between the control (Cd0) and Cd20 soils. However, the abundance of multiple rhizospheric microbial taxa was altered in the Cd20 soil compared with that in the Cd0 soil. Interestingly, many plant growth-promoting microorganisms (e.g., Nocardioides, Flavisolibacter, Rhizobium, Achromobacter, and Penicillium) enriched in the Cd20 soil likely contributed to the growth and vitality of C. grandiflora under Cd stress. Among these, some microorganisms (e.g., Rhizobium, Achromobacter, and Penicillium) likely affected Cd uptake by C. grandiflora. These abundant plant growth-promoting microorganisms potentially interacted with soil pH and the concentrations of Cd and AK in soil. Notably, potassium-solubilizing microbes (e.g., Rhizobium and Penicillium) may effectively solubilize potassium to assist Cd uptake by C. grandiflora. This study provides a new plant resource for Cd phytoextraction and improves our understanding of rhizosphere-associated mechanisms of plant adaptation to Cd-contaminated soil.

Simultaneous Determination and Comparison of Phenolic Bioactives among Three Main Kinds of Edible Chrysanthemums.

In this study, we report a simple and reliable high-performance liquid chromatography coupled with diode array detection method for simultaneous and quantitative analysis and comparison of major phenolic compounds dominant phytochemicals in Chrysanthemum morifolium, Florists chrysanthemum and snow chrysanthemum (Coreopsis tinctoria or C. tinctoria). The chromatographic separation was achieved using a reversed phase C18 column with a mobile phase of water [containing 0.1% trifluoroacetic acid (TFA)] and acetonitrile. The major phenolic compounds were completely separated within 16 min at a flow rate of 1.0 mL/min. Flavonoid and phenolic acid profiles of the ethanol extracts of the three flowers were analyzed. The results revealed that C. tinctoria possessed the highest amount of flavonoids (flavanomarein, flavanokanin, marein and okanin) and relative lower content of phenolic acid (chlorogenic acid and 3,5-dicafeoylquinic acid). The total content of the four flavonoids in C. tinctoria reached 53.99 ± 1.32 mg/g. In particular, the marein content in C. tinctoria was as high as 36.50 mg/g. Flavanomarein was only detected in C. tinctoria, whereas chlorogenic acid and 3,5-dicafeoylquinic acid were abundant in Chrysanthemum morifolium and Florists chrysanthemum. The content of marein in Chrysanthemum morifolium was slightly higher than that in Florists chrysanthemum, whereas no okanin was detected in Florists chrysanthemum under these high-performance liquid chromatography conditions. The results indicated phenolic components differ significantly depending on the cultivar, especially between C. tinctoria and common commercially available chrysanthemums. The method adopted in this study is helpful for quality control of different chrysanthemum species as well as their products, which is essential for usage and functionality clarification.

Mechanisms of Coreopsis tinctoria Nutt in the treatment of diabetic nephropathy based on network pharmacyology analysis of its active ingredients / Mecanismos de Coreopsis tinctoria Nutt. En el tratamiento de la nefropatía diabética basado en el análisis farmacológico de red de sus principios activos

SUMMARY: Coreopsis tinctoria Nutt. (C. tinctoria Nutt.) can protect diabetic kidneys, but the mechanisms are unclear. This work is to investigate the potential mechanisms of C. tinctoria Nutt. in the treatment of diabetic nephropathy based on network pharmacology analysis of its active ingredients. Twelve small molecular compounds of C. tinctoria Nutt. and targets related to diabetic nephropathy were docked by Discovery Studio 3.0. DAVID database was used for GO enrichment and KEGG pathway analysis. Cytoscape 3.6.1 was used to construct active ingredient-target network. Cell viability was detected with MTT. Glucose consumption was analyzed with glucose oxidase method. Protein expression was measured with Western blot and immunofluorescence. Electron microscopy observed autophagosomes. The core active ingredients of C. tinctoria Nutt. included heriguard, flavanomarein, maritimein, and marein. Twenty-one core targets of the 43 potential targets were PYGM, TLR2, RAF1, PRKAA2, GPR119, INS, CSF2, TNF, IAPP, AKR1B1, GSK3B, SYK, NFKB2, ESR2, CDK2, FGFR1, HTRA1, AMY2A, CAMK4, GCK, and ABL2. These 21 core targets were significantly enriched in 50 signaling pathways. Thirty- four signaling pathways were closely related to diabetic nephropathy, of which the top pathways were PI3K/AKT, insulin, and mTOR, and insulin resistance. The enriched GO terms included biological processes of protein phosphorylation, and the positive regulation of PI3K signaling and cytokine secretion; cellular components of cytosol, extracellular region, and extracellular space; and molecular function of protein kinase activity, ATP binding, and non-membrane spanning protein tyrosine kinase activity. In vitro experiments found that marein increased the expression of phosphorylated AKT/AKT in human renal glomerular endothelial cells of an insulin resistance model induced by high glucose, as well as increased and decreased, respectively, the levels of the microtubule-associated proteins, LC3 and P62. C. tinctoria Nutt. has many active ingredients, with main ingredients of heriguard, flavanomarein, maritimein, and marein, and may exert anti-diabetic nephropathy effect through various signaling pathways and targets.

RESUMEN: Coreopsis tinctoria Nutt. (C. tinctoria Nutt.) puede proteger riñones diabéticos, sin embargo los mecanismos son desconocidos. Este trabajo se realizó para investigar los potenciales mecanismos de C. tinctoria Nutt. en el tratamiento de la nefropatía diabética basado en el análisis de farmacología en red de sus principios activos. Doce compuestos moleculares pequeños de C. tinctoria Nutt. y los objetivos relacionados con la nefropatía diabética fueron acoplados por Discovery Studio 3.0. La base de datos DAVID se utilizó para el enriquecimiento GO y el análisis de la vía KEGG. Se usó Cytoscape 3.6.1 para construir una red de ingrediente-objetivo activa. La viabili- dad celular se detectó mediante MTT. El consumo de glucosa se analizó con el método de glucosa oxidasa. La expresión proteica fue determinada mediante Western blot e inmunofluorescencia. En la microscopía electrónica se observó autofagosomas. Los principales ingredientes activos de C. tinctoria Nutt. incluyeron heriguard, flavanomarein, maritimin y marein. Veintiún de los 43 objetivos potenciales fueron PYGM, TLR2, RAF1, PRKAA2, GPR119, INS, CSF2, TNF, IAPP, AKR1B1, GSK3B, SYK, NFKB2, ESR2, CDK2, FGFR1, HTRA1, AMY2A, CAMK4, GCK y ABL2. Estos 21 objetivos principales se enriquecieron significativamente en 50 vías de señalización. Treinta y cuatro vías de señalización estuvieron estrechamente relacionadas con la nefropatía diabética, de las cuales las principales vías fueron PI3K/ AKT, insulina y mTOR, y resistencia a la insulina. Los términos GO enriquecidos incluyeron procesos biológicos de fosforilación proteica, la regulación positiva de la señalización de PI3K y la secreción de citoquinas; componentes celulares del citosol, región extracelular y espacio extracelular; y la función molecular de la actividad de la proteína quinasa, la unión de ATP y la actividad de la proteína tirosina quinasa que no se extiende por la membrana. Los experimentos in vitro encontraron que la mareína aumentaba la expresión de AKT/AKT fosforilada en células endoteliales glomerulares renales humanas en un modelo de resistencia a la insulina inducida por niveles elevados de glucosa, así como aumentaron y disminuyeron respectivamente, los niveles de las proteínas asociadas a los microtúbulos, LC3 y P62. C. tinctoria Nutt. tiene muchos principios activos, con ingredientes principales de heriguard, flavanomarein, maritimain y marein, y puede ejercer un efecto de nefropatía antidiabética a través de distintass vías de señalización y objetivos.

Anti-Neuroinflammatory and Anti-Inflammatory Activities of Phenylheptatriyne Isolated from the Flowers of Coreopsis lanceolata L. via NF-κB Inhibition and HO-1 Expression in BV2 and RAW264.7 Cells.

Aging is associated with immune disregulation and oxidative stress which lead to inflammation and neurodegenerative diseases. We have tried to identify the anti-neuroinflammatory and anti-inflammatory components of Coreopsis lanceolata L. The dried flowers of C. lanceolata were extracted with 70% EtOH, and the obtained extract was divided into CH2Cl2, EtOAc, n-BuOH, and H2O fractions. The CH2Cl2 fraction was separated using silica gel and C-18 column chromatography to yield phenylheptatriyne (1), 2'-hydroxy-3,4,4'-trimethoxychalcone (2), and 4',7-dimethoxyflavanone (3). Additionally, the EtOAc fraction was subjected to silica gel, C-18, and Sephadex LH-20 column chromatography to yield 8-methoxybutin (4) and leptosidin (5). All the compounds isolated from C. lanceolata inhibited the production of nitric oxide (NO) in LPS-induced BV2 and RAW264.7 cells. In addition, phenylheptatriyne and 4',7-dimethoxyflavanone reduced the secretion of inflammatory cytokines, tumor necrosis factor alpha (TNF-α), and interleukin (IL)-6. Among them, phenylheptatriyne was significantly downregulated in the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Subsequently, phenylheptatriyne also effectively inhibited nuclear factor-kappa B (NF-κB) activation in LPS-stimulated BV2 and RAW264.7 cells. Based on these results, the anti-neuroinflammatory effect of phenylheptatriyne isolated from C. lanceolata was confirmed, which may exert a therapeutic effect in treatment of neuroinflammation-related diseases.

Isolation, purification and structural characterization of two pectin-type polysaccharides from Coreopsis tinctoria Nutt. and their proliferation activities on RAW264.7 cells.

Coreopsis tinctoria Nutt. (C.tinctoria) is an annual herb of the Compositae family with many health benefits, such as clearing heat, antioxidant and anticancer activity. In this paper, two polysaccharides were isolated from C.tinctoria, named CTAP-1 and CTAP-2, respectively. Structure of CTAP-1and CTAP-2 were elucidated by high-performance gel permeation chromatography, chemical derivative analyses, GC-MS and NMR techniques. Results reveal that they both CTAP-1 and CTAP-2 consisted of predominant amounts of galacturonic acid residues along with small amounts of arabinose, rhamnose and galactose.Both them contain homogalacturonan and rhammnogalcturan I regions in different ratio, suggesting their pectin-type features. The proliferation activities of CTAP-1 and CTAP-2 on RAW264.7 cells in vitro were detected. Results show both them have the significant proliferation effect on RAW264.7 cells when the concentration from 40 to 200 µg/mL. Given their structural characteristics and proliferation activities, the pectins are expected to be potential natural immune modulators, which need further study.

Traditional uses, phytochemistry, pharmacology, and toxicology of Coreopsis tinctoria Nutt.: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: Coreopsis tinctoria Nutt. (family Asteraceae) is an important traditional medicine in North America, Europe, and Asia for quite a long historical period, which has received great attention due to its health-benefiting activities, including disinfection, treatment sexual infection, diarrhoea, acute and chronic dysentery, red-eye swelling as well as pain, heat, thirst, hypertension, palpitation, gastrointestinal discomfort, and loss of appetite. AIM OF THE REVIEW: The purpose of this review is to give an overview of the current phytochemistry and pharmacological activities of C. tinctoria, and reveals the correlation among its traditional uses, phytochemistry, pharmacological profile, and potential toxicity. MATERIALS AND METHODS: This review is based on published studies and books from electronic sources and library, including the online ethnobotanical database, ethnobotanical monographs, Scopus, SciFinder, Baidu Scholar, CNKI, and PubMed. These reports are related to the traditional uses, phytochemistry, pharmacology, and toxicology of C. tinctoria. RESULTS: Coreopsis tinctoria is traditionally used in diarrhoea, infection, and chronic metabolic diseases. From 1954 to now, more than 120 chemical constituents have been identified from C. tinctoria, such as flavonoids, polyacetylenes, polysaccharides, phenylpropanoids, and volatile oils. Flavonoids are the major bioactive components in C. tinctoria. Current research has shown that its extracts and compounds possess diverse biological and pharmacological activities such as antidiabetes, anti-cardiovascular diseases, antioxidant, anti-inflammatory, protective effects on organs, neuroprotective effects, antimicrobial, and antineoplastic. Studies in animal models, including acute toxicity, long-term toxicity, and genotoxicity have demonstrated that Snow Chrysanthemum is a non-toxic herb, especially for its water-soluble parts. CONCLUSIONS: Recent findings regarding the main phytochemical and pharmacological properties of C. tinctorial have confirmed its traditional uses in anti-infection and treatment of chronic metabolic disease and, more importantly, have revealed the plant as a valuable medicinal plant resource for the treatment of a wide range of diseases. The available reports indicated that most of the bioactivities in C. tinctorial could be attributed to flavonoids. However, higher quality studies on animals and humans studies are required to explore the efficacy and mechanism of action of C. tinctoria in future.

Constituents of Coreopsis lanceolata Flower and Their Dipeptidyl Peptidase IV Inhibitory Effects.

A new polyacetylene glycoside, (5R)-6E-tetradecene-8,10,12-triyne-1-ol-5-O-ß-glucoside (1), was isolated from the flower of Coreopsis lanceolata (Compositae), together with two known compounds, bidenoside C (10) and (3S,4S)-5E-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-ß-glucopyranoside (11), which were found in Coreopsis species for the first time. The other known compounds, lanceoletin (2), 3,2'-dihydroxy-4-3'-dimethoxychalcone-4'-glucoside (3), 4-methoxylanceoletin (4), lanceolin (5), leptosidin (6), (2R)-8-methoxybutin (7), luteolin (8) and quercetin (9), were isolated in this study and reported previously from this plant. The structure of 1 was elucidated by analyzing one-dimensional and two-dimensional nuclear magnetic resonance and high resolution-electrospray ionization-mass spectrometry data. All compounds were tested for their dipeptidyl peptidase IV (DPP-IV) inhibitory activity and compounds 2-4, 6 and 7 inhibited DPP-IV activity in a concentration-dependent manner, with IC50 values from 9.6 to 64.9 µM. These results suggest that C. lanceolata flower and its active constituents show potential as therapeutic agents for diseases associated with type 2 diabetes mellitus.

Identification of Amino Acid Residues Responsible for C-H Activation in Type-III Copper Enzymes by Generating Tyrosinase Activity in a Catechol Oxidase.

Tyrosinases (TYRs) catalyze the hydroxylation of phenols and the oxidation of the resulting o-diphenols to o-quinones, while catechol oxidases (COs) exhibit only the latter activity. Aurone synthase (AUS) is not able to react with classical tyrosinase substrates, such as tyramine and l-tyrosine, while it can hydroxylate its natural substrate isoliquiritigenin. The structural difference of TYRs, COs, and AUS at the heart of their divergent catalytic activities is still a puzzle. Therefore, a library of 39 mutants of AUS from Coreopsis grandiflora (CgAUS) was generated and the activity studies showed that the reactivity of the three conserved histidines (HisA2 , HisB1 , and HisB2 ) is tuned by their adjacent residues (HisB1 +1, HisB2 +1, and waterkeeper residue) either to react as stronger bases or / and to stabilize a position permissive for substrate proton shuffling. This provides the understanding for C-H activation based on the type-III copper center to be used in future biotechnological processes.

Screening of the active fractions from the Coreopsis tinctoria Nutt. Flower on diabetic endothelial protection and determination of the underlying mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: The Coreopsis tinctoria Nutt. flower (CTF) has been used traditionally in China for treating hypertension and diabetes as well as reducing body weight and blood fat. However, the vascular protection effect of the CTF has not been studied to date. AIM OF THE STUDY: This study aimed to screen and identify bioactive fractions from the CTF with a diabetic endothelial protection effect and to clarify the underlying mechanism. MATERIALS AND METHODS: The vascular protection effect of Fraction A was studied in high-fat diet and streptozocin-induced diabetic models. The endothelial protection effect of Fraction A-2 was further studied in an in vitro vascular endothelial dysfunction model induced by high glucose. In a high glucose-induced human umbilical vein endothelial cell (HUVEC) model, Fractions A-2-2 and A-2-3 were screened, and their detailed mechanisms of endothelial protection were studied. Liquid chromatography mass spectrometry (LC-MS) was used to identify the main components in Fractions A-2-2 and A-2-3. RESULTS: Fraction A treatment significantly improved the endothelium-dependent vasodilation of the mesenteric artery induced by acetylcholine in diabetic rats. The maximum relaxation was 79.82 ± 2.45% in the control group, 64.36 ± 9.81% in the model group, and 91.87 ± 7.38% in the Fraction A treatment group (P < 0.01). Fraction A treatment also decreased rat tail pressure compared with the model group at the 12th week. The systolic blood pressure was 152.7 5 ± 16.99 mmHg in the control group, 188.50 ± 5.94 mmHg in the model group, and 172.60 ± 14.31 mmHg in the Fraction A treatment group (P < 0.05). The mean blood pressure was 128.50 ± 13.79 mmHg in the control group, 157.00 ± 6.06 mmHg in the model group, and 144.80 ± 11.97 mmHg in the Fraction A treatment group (P < 0.05). In an in vitro vascular endothelium-dependent vasodilation dysfunction model induced by high glucose, Fraction A-2 improved the vasodilation of the mesenteric artery. The maximum relaxation was 82.15 ± 16.24% in the control group, 73.29 ± 14.25% in the model group, and 79.62 ± 13.89% in the Fraction A-2 treatment group (P < 0.05). In a high glucose-induced HUVEC model, Fraction A-2-2 and Fraction A-2-3 upregulated the expression of IRS-1, Akt, and eNOS and increased the levels of p-IRS-1Ser307, p-Akt Ser473, and p-eNOSSer1177 and also decreased the expression of NOX4, TNF-α, IL-6, sVCAM, sICAM, and NF-κB (P < 0.01). With the intervention of AG490 and LY294002, the above effects of Fraction A-2-2 and Fraction A-2-3 were inhibited (P < 0.01). LC-MS data showed that in Fraction A-2-2 and Fraction A-2-3, there were 10 main components: flavanocorepsin; polyphenolic; flavanomarein; isochlorogenic acid A; dicaffeoylquinic acid; coreopsin; marein; coreopsin; luteolin-7-O-glucoside; and 3',5,5',7-tetrahydroxyflavanone-O-hexoside. CONCLUSION: The protective effect of the CTF on diabetic endothelial dysfunction may be due to its effect on the JAK2/IRS-1/PI3K/Akt/eNOS pathway and the related oxidative stress and inflammation. The results strongly suggested that Fraction A-2-2 and Fraction A-2-3 were the active fractions from the CTF, and the CTF might be a potential option for the prevention of vascular complications in diabetes.

[Protective Effect of a Dihydroflavonol Glycoside from Coreopsis tinctoria Nutt. in Mouse Model of Alcoholic Acute Pancreatitis].

OBJECTIVE: To investigate the protective effect of (2R, 3R)-dihydroquercetin 7-O-ß-D-glucopyranose (C1) extracted from Coreopsis tinctoria Nutt. in a mouse model of alcoholic acute pancreatitis (FAEE-AP) induced byfatty acid ethyl ester (FAEE). METHODS: The 30 healthy SPF mice were randomly divided into control group, model group, low dose group, middle dose group and high dose group, 6 in each group. Alcoholic pancreatitis was induced by ethanol and palmitoleic acid administration (1.75 g/kg ethanol, 200 mg/kg palmitoleic acid, 2 times peritoneal injections). The three treatment groups were given C1 (0 h, 4 h, 8 h) at the dose of 12.5, 25 and 50 mg/kg, respectively. After 24 h of molding, the serum amylase, lipase and IL-6 levels were detected. The trypsin level in pancreatic tissue and myeloperoxidase (MPO) level in pancreatic and lung tissue were detected. Hematoxylin-eosin (HE) staining was used to observe the pathological changes of pancreatic tissue and immunohistochemical (IHC) staining was used to detect the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) in pancreatic tissue. RESULTS: The pancreatic histopathological scores, serum amylase and lipase activity, trypsin level in pancreatic tissue, serum IL-6 level, MPO level of pancreas and lung were significantly higher in the model group than in the control group (P < 0.01). Compared with the model group, the pancreatic histopathologies of the low dose group was significantly improved (P < 0.05), as well as the serum amylase and lipase activity, trypsin level of pancreas, serum IL-6 level, the pancreas andthe lung's MPO level decreased significantly (P < 0.05), and up-regulate that expression of Nrf2 in pancreatic tissue. CONCLUSION: 12.5 mg/kg of (2R, 3R) -dihydroquercetin 7-O-ß-D-glucopyranose (C1) improved the expression of Nrf2, reduced the expression of inflammatory factor IL-6, and protected acute pancreatitis caused by FAEE.

Structural elucidation and bioactivities of a novel arabinogalactan from Coreopsis tinctoria.

Coreopsis tinctoria is being widely cultivated in Xinjiang of China, whose consumption is known to prevent diabetes and neurodegenerative diseases. To elucidate the bioactive ingredients responsible for these benefits, the alkaline soluble crude polysaccharide (CTB) was isolated from C. tinctoria. In vitro experiments showed that the inhibition of α-amylase and α-glucosidase by CTB was 13407-fold and 906-fold higher than that by positive control, respectively. Then, a novel arabinogalactan, CTBP-1, was isolated and purified from CTB. Structural analysis showed that CTBP-1 possessed a 1,6-linked ß-d-Galp and 1,5-linked α-l-Araf backbone with branches substituted at the C-3 position of the 1,6-linked ß-d-Galp, and the side chains included 1,5-linked α-l-Araf, T-linked ß-d-Galp and T-linked α-l-Araf. The inhibitory effects of CTBP-1 on α-amylase and α-glucosidase were 2.7 and 17.9 times that of acarbose, respectively. CTBP-1 could avoid indigestion and similar side effects. In addition, CTBP-1 remarkably inhibited the release of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. In summary, CTBP-1 is a novel arabinogalactan with great potential as a treatment for type 2 diabetes and Alzheimer's disease.

The Alcohol Extract of Coreopsis tinctoria Nutt Ameliorates Diabetes and Diabetic Nephropathy in db/db Mice through miR-192/miR-200b and PTEN/AKT and ZEB2/ECM Pathways.

The study aims to investigate the effects of the alcohol extract of Coreopsis tinctoria Nutt (AC) on diabetic nephropathy (DN) mice. A total of 30 db/db (DN) mice were divided into 3 groups, which were treated with AC (300 mg/kg/day), metformin (180 mg/kg/day), or saline by gavage for 10 weeks. Ten db/m mice treated with saline were used as normal control (NC group). Body weight (BW) and fasting blood glucose (FBG), HbA1c, 24 h urinary albumin excretion (UAE), and renal pathological fibrosis were analyzed. Expression of miR-192, miR-200b, and proteins in the PTEN/PI3K/AKT pathway was analyzed by qPCR or western blot. The DN mice had significantly higher BW, FBG, and 24 h UAE, as well as more severe pathological fibrosis when compared with NC. Treatment of AC could decrease BW, FBG, and 24 h UAE and alleviated kidney damage. Compared with the NC group, expressions of miR-192 and miR-200b were increased, whereas their target proteins (ZEB2 and PTEN) were reduced in the kidneys of DN mice, which further modulated the expression of their downstream proteins PI3K p85α, P-AKT, P-smad3, and COL4 α1; these proteins were increased in the kidneys of DN mice. In contrast, AC treatment reversed the expression changes of these proteins. These findings demonstrate that AC may protect the kidneys of DN mice by decreasing miR-192 and miR-200b, which could further regulate their target gene expression and modulate the activity of the PTEN/PI3K/AKT pathway to reduce the degree of renal fibrosis.

Structural characterization of a polysaccharide from Coreopsis tinctoria Nutt. and its function to modify myeloid derived suppressor cells.

Coreopsis tinctoria Nutt. (C. tinctoria) is a natural plant with many health benefits, such as clearing heat and toxic materials. In this study, we investigate the effect of a polysaccharide from C. tinctoria, aiming at improving the tumor microenvironment, which is associated with non-resolving inflammation. Through combining ion-exchange and gel permeation chromatography, a polysaccharide named CTAP-3 is purified from the crude polysaccharides of C. tinctoria. The structure of CTAP-3 is characterized through high-performance gel permeation chromatography, chemical derivative analyses, GC-MS, FT-IR, and NMR. Results reveal that CTAP-3 consists of predominant amounts (87.2%) of galacturonic acid (GalA) residues, small amounts of arabinose (Ara) and rhamnose (Rham), and trace amounts of galactose (Gal). CTAP-3 is deduced to be native pectin-type polysaccharide containing a homo-galacturanan backbone consisting of α-(1 → 4)-linked GalAp and methyl-esterified α-(1 → 4)-linked GalAp residues in the ratio of 4:1. When myeloid-derived suppressor cells (MDSCs) are treated by CTAP-3, its suppressive effect on T cell proliferation is impaired. This result indicates that CTAP-3 is a candidate drug for improving the tumor microenvironment.