De-An Guo

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (249)569.09 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: An efficient and target-oriented sample enrichment method was established to increase the content of the minor alkaloids in crude extract by using the corresponding two-phase solvent system applied in pH-zone-refining counter-current chromatography. The enrichment and separation of seven minor indole alkaloids from Uncaria rhynchophylla (Miq.) Miq. ex Havil(UR) were selected as an example to show the advantage of this method. An optimized two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (3:7:1:9, v/v) was used in this study, where triethylamine (TEA) as the retainer and hydrochloric acid (HCl) as the eluter were added at the equimolar of 10mM. Crude alkaloids of UR dissolved in the corresponding upper phase (containing 10mM TEA) were extracted twice with lower phase (containing 10mM TEA) and lower phase (containing 10mM HCl), respectively, the second lower phase extract was subjected to pH-zone-refining CCC separation after alkalization and desalination. Finally, from 10g of crude alkaloids, 4g of refined alkaloids was obtained and the total content of seven target indole alkaloids was increased from 4.64% to 15.78%. Seven indole alkaloids, including 54mg isocorynoxeine, 21mg corynoxeine, 46mg isorhynchophylline, 35mg rhynchophylline, 65mg hirsutine, 51mg hirsuteine and 27mg geissoschizine methylether were all simultaneously separated from 2.5g of refined alkaloids, with the purity of 86.4%, 97.5%, 90.3%, 92.1%, 98.5%, 92.3%, and 92.8%, respectively. The total content and purities of the seven minor indole alkaloids were tested by HPLC and their chemical structures were elucidated by ESI-HRMS and (1)H NMR. Copyright © 2015. Published by Elsevier B.V.
    Journal of Chromatography A 07/2015; DOI:10.1016/j.chroma.2015.07.066 · 4.26 Impact Factor
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    ABSTRACT: Despite the numerous pharmacological agents available for hypertension therapy, hypertension-related microvascular remodeling is not resolved, eventually leading to end-organ damage. The aim of the present study was to investigate the protection of salvianolic acid A (SalA) against microvascular remodeling in vitro and in vivo. Spontaneously hypertensive rats (SHR) were administered 2.5, 5 or 10 mg/kg SalA via intraperitoneal injection once a day for 4 weeks. The tail-cuff method was applied to monitor blood pressure; the microvascular structure of retina was detected by hematoxylin-eosin and immunohistochemical staining; the function of mesenteric arteries was measured by DMT wire myography; endothelial cell proliferation was estimated using Cell Counting Kit 8; endothelial cell migration was evaluated by wound healing and transwell assay; and endothelial cell integrity was detected by transendothelial electrical resistance and permeability assays. Although no antihypertensive effects of SalA were observed, SalA attenuated the microvascular inward remodeling of the retina and improved microvascular function in the mesenteries in vivo. Further cell experiments confirmed the beneficial effects of SalA on the integrity of the endothelial monolayer in vitro. Salvianolic acid A inhibited endothelial dysfunction and vascular remodeling in spontaneously hypertensive rats. Therefore, salvianolic acid A could be a potential drug therapy to prevent further targeted organ damage induced by vascular remodeling. Copyright © 2015. Published by Elsevier Inc.
    Life sciences 06/2015; DOI:10.1016/j.lfs.2015.06.010 · 2.30 Impact Factor
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    ABSTRACT: Current China Pharmacopoeia (ChP) standards employ diversified and case-dependent assay methods to evaluate the quality of different Chinese patent medicines (CPMs) that contain Panax notoginseng as the monarch drug. These conventional, HPLC-based approaches, utilizing a complex sample preparation procedure, can easily result in low analytical efficiency and possible component loss. Here, a "monomethod-heterotrait matrix" (MHM) strategy is proposed, that is, developing a universal multi heart-cutting two-dimensional liquid chromatography (MHC-2D-LC) approach that facilitates the simultaneous quantitation of five P. notoginseng saponins (noto-R1, Re, Rg1, Rb1, and Rd) in eight different CPMs. The MHC-2D-LC system was constructed on a dual-gradient liquid chromatography instrument equipped with a Poroshell SB C18 column and a Zorbax SB-Aq column for respective (1)D and (2)D separation. Method validation was performed in terms of specificity, linearity (r(2) and F-test), intra-/inter-day precision (0.4-7.9%), stability (1.2-3.9%), and recovery (90.2-108.7%), and the LODs and LOQs (loaded masses) of the five analytes varied between 4.0-11.0ng and 6.0-33.0ng, respectively. The validated MHC-2D-LC approach was subsequently applied to quantify the five saponins in thirty batches of different CPMs. The method demonstrated superiority over the current ChP assay methods in respect of specificity (avoiding co-elution), resolution (Rs>1.5), sample preparation (easy-to-implement ultrasonic extraction without repeated re-extraction), and transfer rate (minimum component loss). This is the first application of an MHC-2D-LC method for the quantitative assessment of the constituents of CPMs. The MHM approach represents a new, strategically significant methodology for the quality control of CPMs that involve complex chemical matrix. Copyright © 2015 Elsevier B.V. All rights reserved.
    Journal of Chromatography A 05/2015; 1402. DOI:10.1016/j.chroma.2015.05.015 · 4.26 Impact Factor
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    ABSTRACT: One new 19-norbufadienolide (1) and one new bufogargarizin (2), together with twelve known bufadienolides (3-14, resp.) were isolated from Chan Su, a traditional Chinese medicine that is used in the treatment of cancer. Their structures were elucidated on the basis of detailed spectroscopic analysis and comparison of corresponding data that is previously reported. The cytotoxic activities of the isolated compounds were evaluated on HeLa and A549 cell lines. Though 1 and 2 showed weak cytotoxic activities on both cell lines, compounds 4 and 5 showed lower IC50 values than bufalin, the most widely studied bufadienolide in Chan Su. Furthermore, four 3-ester derivatives (15-18) of compound 4 were synthesized and their cytotoxic activities were also evaluated. Analysis of the structure-activity relationship indicated that bufadienolides with aldehyde group at C-10 or α-hydroxyl group at C-11 exhibit stronger cytotoxic activities on both cell lines. The cytotoxic activity of arenobufagin-3-ester derivative 17 was 4-fold higher than compound 4. Copyright © 2015. Published by Elsevier B.V.
    Fitoterapia 05/2015; 104:1-6. DOI:10.1016/j.fitote.2015.05.011 · 2.22 Impact Factor
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    ABSTRACT: Licorice is one of the most popular herbal medicines worldwide. It contains a big array of phenolic compounds (flavonoids, coumarins, and diphenylethanones). Due to high structural diversity, low abundance, and co-elution with licorice saponins, these phenolic compounds are difficult to be separated by conventional chromatography. In this study, a mobile phase-dependent reversed-phase×reversed phase comprehensive two-dimensional liquid chromatography (RP×RP 2DLC) method was established to separate phenolic compounds in licorice (the roots of Glycyrrhiza uralensis). Organic solvents in the mobile phase were optimized to improve orthogonality of the first and second dimensions, and a synchronized gradient mode was used to improve chromatographic resolution. Finally, licorice extracts were eluted with methanol/water/formic acid in the first dimension (Acquity CSH C18 column), and acetonitrile/water/formic acid in the second dimension (Poroshell Phenyl-Hexyl column). By using this 2DLC system, a total of 311 compounds were detected within 40min. The practical and effective peak capacity was 1329 and 524, respectively, and the orthogonality was 79.8%. The structures of 21 selected unknown compounds were tentatively characterized by mass spectrometry, and 8 of them were discovered from G. uralensis for the first time. The mobile phase-dependent 2DLC/MS system could benefit the separation and characterization of natural products in complicated herbal extracts. Copyright © 2015 Elsevier B.V. All rights reserved.
    Journal of Chromatography A 05/2015; 1402. DOI:10.1016/j.chroma.2015.05.006 · 4.26 Impact Factor
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    ABSTRACT: Antrodia cinnamomea is a precious medicinal mushroom popularly used for adjuvant cancer therapy in Taiwan. Its major bioactive constituents are ergostane and lanostane triterpenoids. Although clinical trials for A. cinnamomea have been recently initiated, its metabolism remains unclear. The present study aims to elucidate the metabolism and pharmacokinetics of A. cinnamomea in rats. After oral administration of an ethanol extract, 18 triterpenoids and 8 biotransformed metabolites were detected in rats plasma by UHPLC/qTOF-MS. Four of the metabolites were prepared by semi-synthesis and fully identified by NMR, while the others were tentatively characterized by comparing with the metabolites of single compounds (antcins B, C, H and K). Furthermore, a multi-component pharmacokinetic study of A. cinnamomea was carried out to monitor the plasma concentrations of 14 triterpenoids (ergostanes 1-3, 5-8, 14-16; lanostanes 9, 10, 17, 19) and 2 metabolites (M5, M6) by LC/MS/MS in rats after oral administration of the ethanol extract (1.0g/kg). The results showed that ergostanes and Δ(7,9(11)) lanostanes, but not Δ(8) lanostanes, could get into circulation. The low-polarity ergostanes (antcins B and C) undertook hydrogenation (C-3 or C-7 carbonyl groups) or hydroxylation to produce polar metabolites. High-polarity ergostanes (antcins H and K) and Δ(7,9(11)) lanostanes were metabolically stable. We also discovered that ergostanes and lanostanes showed remarkably different pharmacokinetic patterns. The ergostanes were generally absorbed and eliminated rapidly, whereas the lanostanes remained in the plasma at a low concentration for a relatively long time. The results indicate that high-polarity ergostanes are the major plasma-exposed components of A. cinnamomea, and may play an important role in its therapeutic effects. Copyright © 2015 Elsevier B.V. All rights reserved.
    Journal of pharmaceutical and biomedical analysis 04/2015; 111:266-276. DOI:10.1016/j.jpba.2015.04.010 · 2.83 Impact Factor
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    ABSTRACT: Coumarins are an important group of bioactive constituents in licorice (Glycyrrhiza uralensis), a worldwide popular herbal medicine. This study aims to elucidate the metabolism of two major licorice coumarins, glycyrin and glycyrol in rats. After oral administration of 40 mg/kg glycyrin, neither the parent compound nor its metabolites could be detected in rats plasma or urine samples, indicating that glycyrin had poor oral bioavailability. Two hydroxylated metabolites, 4″-hydroxyl glycyrin and 5″-hydroxyl glycyrin, were detected in rat liver microsome incubation system. Among them, the major metabolite 4″-hydroxyl glycyrin, which is a new compound, was obtained by microbial transformation of Syncephalastrum racemosum AS 3.264. Its structure was fully identified by 1D and 2D NMR. Meanwhile, glycyrol, together with three metabolites, were detected in rats urine and fecal samples after oral administration (40 mg/kg). Their structures were tentatively characterized by LC/MS. Glycyrol mainly undertakes hydroxylation metabolism, accompanied by hydration and dehydrogenation as minor reactions. This is the first systematic study on metabolism of glycyrin and glycyrol. The results could be valuable to evaluate druggability of these bioactive natural products.
    Journal of Chromatography B 03/2015; 983. DOI:10.1016/j.jchromb.2014.12.028 · 2.69 Impact Factor
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    ABSTRACT: Coumarinlignan (1), possessing a unique coumarin-containing lignan skeleton, was isolated from the stems of Kadsura heteroclita. Its structure and absolute configuration were determined by spectroscopic techniques, especially 2D NMR and X-ray crystallographic data analyses. The proposed biosynthetic pathway is discussed. This new compound showed good anti-HBV activity against HBeAg and HBsAg, and moderate anti-fibrotic and neuroprotective activities. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Bioorganic & Medicinal Chemistry Letters 02/2015; 25(7). DOI:10.1016/j.bmcl.2015.02.022 · 2.33 Impact Factor
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    ABSTRACT: Gambogic acid (GA) is an anticancer agent in phase ‖b clinical trial in China but its mechanism of action has not been fully clarified. The present study was designed to search the possible target-related proteins of GA in cancer cells using proteomic method and establish possible network using bioinformatic analysis. Cytotoxicity and anti-migration effects of GA in MDA-MB-231 cells were checked using MTT assay, flow cytometry, wound migration assay, and chamber migration assay. Possible target-related proteins of GA at early (3 h) and late stage (24 h) of treatment were searched using a proteomic technology, two-dimensional electrophoresis (2-DE). The possible network of GA was established using bioinformatic analysis. The intracellular expression levels of vimentin, keratin 18, and calumenin were determined using Western blotting. GA inhibited cell proliferation and induced cell cycle arrest at G2/M phase and apoptosis in MDA-MB-231 cells. Additionally, GA exhibited anti-migration effects at non-toxic doses. In 2-DE analysis, totally 23 possible GA targeted proteins were found, including those with functions in cytoskeleton and transport, regulation of redox state, metabolism, ubiquitin-proteasome system, transcription and translation, protein transport and modification, and cytokine. Network analysis of these proteins suggested that cytoskeleton-related proteins might play important roles in the effects of GA. Results of Western blotting confirmed the cleavage of vimentin, increase in keratin 18, and decrease in calumenin levels in GA-treated cells. In summary, GA is a multi-target compound and its anti-cancer effects may be based on several target-related proteins such as cytoskeleton-related proteins. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.
    Chinese Journal of Natural Medicines 01/2015; 13(1):41-51. DOI:10.1016/S1875-5364(15)60005-X
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    ABSTRACT: Two new sesquiterpene lactone dimers, neojaponicone B (1) and inulanolide E (2) along with five known sesquiterpene lactone dimers (3-7, resp.) were isolated from the aerial parts of Inula japonica Thunb. The chemical structures of 1 and 2 were elucidated by detailed spectroscopic analysis. The relative configuration of 2 was confirmed by biomimetic transformation from the known sesquiterpene lactone dimer inulanolide A (3). The cytotoxicities of the isolated sesquiterpene lactone dimers were evaluated against 6T-CEM and Jurkat cell lines. All compounds showed potent cytotoxicities with IC50 value of 2.2-5.9μm. Copyright © 2015. Published by Elsevier B.V.
    Fitoterapia 01/2015; 101. DOI:10.1016/j.fitote.2015.01.011 · 2.22 Impact Factor
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    ABSTRACT: A high performance liquid chromatographic (HPLC) fingerprint is commonly used for quality consistency evaluation of herbal medicines. Recently, an improved chromatographic technique resulted in ultra high performance liquid chromatography (UHPLC), which could provide higher resolution in less time under higher pressure using finer particles (less than 2μm) of stationary phase. A simple and sensitive method was developed and validated for fingerprint analysis of Penthorum chinense Pursh (PC), with the simultaneous determination of seven components using UPLC coupled with a diode-array detector (DAD). It took less than 20 min for analysis of one sample. Both similarity analysis and principle components analysis (PCA) were employed to evaluate the quality consistency of 17 sample batches. The analysis was performed on a Waters ACQUITY UPLC HSS T3 (2.1 x 150 mm, 1.7 μm) column, which was maintained at 45°C and the eluents were monitored with DAD at 270 nm. A gradient elution with acetonitrile and water containing 0.075% phosphoric acid was used. The solvent flow rate was 0.4 mL/min. Standard calibration curves showed good linear behavior (R2 > 0.9994) in the range of 0.20-337.05 μg/mL. Acceptable repeatability (RSD < 0.61%), reproducibility (RSD < 2.72%), stability (RSD < 1.59%) and recovery in the range of 94.7%-102.9% were obtained (precision and accuracy). The validated method was successfully applied to evaluate the quality of 21 samples of PC.
    Natural product communications 01/2015; 10(1):71-6. · 0.92 Impact Factor
  • 01/2015; 1(1):1-4. DOI:10.15806/j.issn.2311-8571.2014.0027
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    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.089 · 0.65 Impact Factor
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    Min Yang, Shanshan Wei, De-an Guo
    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.066 · 0.65 Impact Factor
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    ABSTRACT: Chinese patent medicines (CPM), generally prepared from several traditional Chinese medicines (TCMs) in accordance with specific process, are the typical delivery form of TCMs in Asia. To date, quality control of CPMs has typically focused on the evaluation of the final products using fingerprint technique and multi-components quantification, but rarely on monitoring the whole preparation process, which was considered to be more important to ensure the quality of CPMs. In this study, a novel and effective strategy labeling "retracing" way based on HPLC fingerprint and chemometric analysis was proposed with Shenkang injection (SKI) serving as an example to achieve the quality control of the whole preparation process. The chemical fingerprints were established initially and then analyzed by similarity, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) to evaluate the quality and to explore discriminatory components. As a result, the holistic inconsistencies of ninety-three batches of SKIs were identified and five discriminatory components including emodic acid, gallic acid, caffeic acid, chrysophanol-O-glucoside, and p-coumaroyl-O-galloyl-glucose were labeled as the representative targets to explain the retracing strategy. Through analysis of the targets variation in the corresponding semi-products (ninety-three batches), intermediates (thirty-three batches), and the raw materials, successively, the origins of the discriminatory components were determined and some crucial influencing factors were proposed including the raw materials, the coextraction temperature, the sterilizing conditions, and so on. Meanwhile, a reference fingerprint was established and subsequently applied to the guidance of manufacturing. It was suggested that the production process should be standardized by taking the concentration of the discriminatory components as the diagnostic marker to ensure the stable and consistent quality for multi-batches of products. It is believed that the effective and practical strategy would play a critical role in the guidance of manufacturing and help improve the safety of the final products.
    PLoS ONE 12/2014; 10(3):e0121366. DOI:10.1371/journal.pone.0121366 · 3.53 Impact Factor
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    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.100 · 0.65 Impact Factor
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    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.060 · 0.65 Impact Factor
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    ABSTRACT: To elucidate the chemical components of Xueshuantong (XST) Lyophilized Powder and primarily disclose the chemical difference between XST and Panax notoginseng roots.
    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.062 · 0.65 Impact Factor
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    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.064 · 0.65 Impact Factor
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    European Journal of Integrative Medicine 12/2014; 6(6). DOI:10.1016/j.eujim.2014.09.063 · 0.65 Impact Factor

Publication Stats

3k Citations
569.09 Total Impact Points

Institutions

  • 2007–2015
    • Chinese Academy of Sciences
      • Research Center for Modernization of Traditional Chinese Medicine
      Peping, Beijing, China
  • 2002–2015
    • Peking University
      • • State Key Laboratory of Natural and Biomimetic Drugs
      • • School of Pharmaceutical Sciences
      • • Modern Research Center for Traditional Chinese Medicine
      Peping, Beijing, China
  • 2006–2014
    • Shanghai Institutes for Biological Sciences
      Shanghai, Shanghai Shi, China
  • 2009–2013
    • Shenyang Pharmaceutical University
      • • Department of Pharmacy
      • • College of Traditional Chinese Materia Medica
      Feng-t’ien, Liaoning, China
  • 2008–2013
    • China Pharmaceutical University
      • College of Traditional Chinese Medicine
      Nan-ching-hsü, Jiangxi Sheng, China
  • 2012
    • Shanghai Research Institute of Materials
      Shanghai, Shanghai Shi, China
    • China Academy of Traditional Chinese Medicine
      Peping, Beijing, China
  • 2007–2011
    • Peking University Health Science Center
      Peping, Beijing, China
  • 2008–2010
    • Shanghai University of Traditional Chinese Medicine
      • Department of Chinese Materia Medica
      Shanghai, Shanghai Shi, China
  • 2005
    • Tianjin University
      T’ien-ching-shih, Tianjin Shi, China