Li-Mei Li

Chengdu Medical College, Hua-yang, Sichuan, China

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Publications (51)127.74 Total impact

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    ABSTRACT: Immunosuppressants are widely used for treatment of T cell-mediated autoimmune diseases and allogeneic graft rejection. However, because of the toxicity and tolerance of these drugs, novel immunosuppressants are urgently needed. We synthesized a series of novel water-soluble benzothiazole derivatives and found that BD926 [sodium 2-(benzo[d]thiazol-2-yl)-4,5,6,7-tetrahydro-2H-indazol-3-olate] had potent immunosuppressive activity. Treatment with BD926 significantly inhibited anti-CD3/anti-CD28 and alloantigen-induced human T cell proliferation as well as IL2-stimulated activated T cell proliferation in a dose-dependent manner in vitro. BD926 had no obvious cytotoxicity against human resting T cells, IL-4 treated activated T cells and fibroblast-like synoviocytes in our experimental conditions. Furthermore, BD926 induced cell cycle arrest at G0/G1 phase and inhibited the cyclin D3 and CDK 6 expression in activated T cells. BD926 inhibited the STAT5, but not Akt and p70S6K, phosphorylation in a dose-dependent manner in the IL-2-treated activated T cells. Interestingly, BD926 inhibited IFN-γ, IL-6 and IL-17, but not IL-2, IL-4 and IL-10, production in activated T cells. Finally, treatment with BD926 reduced delayed-type hypersensitivity in mice in a dose-dependent manner. Collectively, these data suggest that BD926 may be a lead compound for the design and development of new immunosuppressants for the intervention of allograft rejection and autoimmune diseases. Copyright © 2015. Published by Elsevier B.V.
    European journal of pharmacology 04/2015; 761. DOI:10.1016/j.ejphar.2015.04.033 · 2.53 Impact Factor
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    ABSTRACT: Comastomaxanthones A–C (1–3), three new xanthones with a rare 2-oxoprenyl substituent, along with three known ones (4–6) were isolated from the aerial parts of Comastoma pedunculatum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. In addition, compounds 1–6 were tested for their anti-tobacco mosaic virus activity. The results showed that all isolated compounds exhibited weak anti-TMV activity with IC50 values ranging from 122.7 to 242.9 μM.
    Phytochemistry Letters 01/2015; 11. DOI:10.1016/j.phytol.2015.01.006 · 1.45 Impact Factor
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    ABSTRACT: Three representative monoterpenoid indole alkaloids isolated from the trunk barks of Winchia calophylla were investigated using electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) in positive-ion mode. The major CID-fragmentation patterns are the neutral losses of H2O, CH3NH2 (C2H5N or C3H7N), CH2O, HCOOCH3 (HCOOH or CO2), and C4H6 molecules and CH3 radical. High-abundance radical ions at m/z 219, 217, and 205 are formed from corresponding precursor ions by loss of a CH3 radical. The product ion at m/z 168, 144, and 130 in the low-mass range are the characteristic ions of the indole part. A pair of isomers was distinguished unambiguously based on MS/MS spectra. The proposed fragmentation pathways were further supported by ESI-MS/MS/MS and D-labeling experiments.
    Chemistry of Natural Compounds 01/2015; 51(1). DOI:10.1007/s10600-015-1215-x · 0.51 Impact Factor
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    ABSTRACT: A new prenylated chalcone, renifchalcone A (1) was isolated from the whole plants of Desmodium renifolium. Its structure was determined by spectroscopic methods, including 1D and 2D-NMR techniques. Compounds 1 was tested for their cytotoxicity against five human tumor cell lines, NB4, A549, SHSY5Y, PC3 and MCF7 and it showed potential cytotoxicity against A549 and MCF7 cell lines with IC50values of 5.8 and 6.2 μM, respectively.
    Asian Journal of Chemistry 01/2015; 27(7):2733-2734. DOI:10.14233/ajchem.2015.17889 · 0.45 Impact Factor
  • Asian Journal of Chemistry 01/2015; 27(6):2349-2350. DOI:10.14233/ajchem.2015.17808 · 0.45 Impact Factor
  • Heterocycles 01/2015; 91(3):604. DOI:10.3987/COM-14-13165 · 1.08 Impact Factor
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    ABSTRACT: In this study, a benzimidazole derivative named BMT-1 is revealed as a potential immunomodulatory agent. BMT-1 inhibits the activity of H+/K+-ATPases from anti-CD3/CD28 activated T cells. Furthermore, inhibition the H+/K+-ATPases by use of BMT-1 should lead to intracellular acidification, inhibiting T cell proliferation. To explore this possibility, the effect of BMT-1 on intracellular pH changes was examined by using BCECF as a pH-dependent fluorescent dye. Interestingly, increases in the pHi were observed in activated T cells, and T cells treated with BMT-1 showed a more acidic intracellular pH. Finally, BMT-1 targeted the H+/K+-ATPases and inhibited the proliferative response of anti-CD3/CD28-stimulated T cells. A cell cycle analysis indicated that BMT-1 arrested the cell cycle progression of activated T cells from the G1 to the S phase without affecting CD25 expression or interleukin-2 (IL-2) production; treating IL-2-dependent PBMCs with BMT-1 also led to the inhibition of cell proliferation. Taken together, these findings demonstrate that BMT-1 inhibits the proliferation of T cells by interfering with H+/K+-ATPases and down-regulating intracellular pHi. This molecule may be an interesting lead compound for the development of new immunomodulatory agents.
    Molecules 11/2014; 19(11):17173-86. DOI:10.3390/molecules191117173 · 2.42 Impact Factor
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    ABSTRACT: Two new 7,8-secolignans, neglectahenols E and F (1 and 2), together with four known 7,8-secolignans (3-6), were isolated from the fruits of Schisandra neglecta. The structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1-6 were tested for their anti-tobacco mosaic virus (anti-TMV) activities at the concentration of 20 μM. Compounds 1 and 6 showed high anti-TMV activities with inhibition rates of 38.2% and 32.7%, respectively. These rates are higher than that of a positive control. Compounds 2-5 also showed modest anti-TMV activities with inhibition rates in the range of 22.8-28.7%. These rates are close to that of a positive control.
    Journal of Asian Natural Products Research 10/2014; 17(1):1-6. DOI:10.1080/10286020.2014.966697 · 0.91 Impact Factor
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    ABSTRACT: Scopariusic acid (1), a new ent-clerodane-based meroditerpenoid with a unique cyclobutane ring and an unusual 1-octen-3-ol substituent, together with its biosynthetic related compound 2, were isolated from the aerial parts of Isodon scoparius. The structures of 1 and 2, including their absolute configurations, were determined by spectroscopic methods, single-crystal X-ray diffraction analysis, and chemical methods. Compound 1 showed weak cytotoxicity and moderate immunosuppressive activity.
    Organic Letters 08/2013; 15(17). DOI:10.1021/ol401991u · 6.36 Impact Factor
  • Rapid Communications in Mass Spectrometry 12/2012; 26(24):2924-6. DOI:10.1002/rcm.6410 · 2.25 Impact Factor
  • Guo-Bo Xu · Li-Mei Li · Tao Yang · Guo-Lin Zhang · Guo-You Li
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    ABSTRACT: Chaetoconvosins A and B (1 and 2), two novel cytochalasan alkaloids with a new 6/6/5/5/7 pentacyclic ring system, were isolated from the solid-state fermented medium of the wheat rhizospheric fungus Chaetomium convolutum cib-100. Their structures were elucidated on the basis of spectroscopic data. The structure of chaetoconvosin A (1) was confirmed by X-ray crystallographic analysis. Chaetoconvosin B (2), the major metabolite, showed remarkable inhibitory ability on root elongation and moderate cytotoxicity against several cancer cell lines.
    Organic Letters 11/2012; 14(23). DOI:10.1021/ol302943v · 6.36 Impact Factor
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    ABSTRACT: Chaetoglobosins are a family of macrocyclic polyketide alkaloids. They possess many similar isomers and exhibit a wide range of biological activities. Thus, there is a need for reliable, fast, and low-cost analysis of this class of compounds. A series of seven chaetoglobosins from Chaetomium globosum, including two types of isomers, were investigated using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) in both positive- and negative-ion mode. The identity of major product ions was supported by deuterium-labeling experiments. In positive-ion mode, the product ion at m/z 130 is the characteristic ion of the indolyl group. A McLafferty rearrangement might play a significant role in the fragmentation of the macrocycle moiety for most chaetoglobosins and produces two series of characteristic product ions, accompanied by neutral losses. The characteristic product ion at m/z 309 in the MS/MS spectrum of chaetoglobosins E indicates the structure of the cyclic olefinic bond in ring B and can be used to distinguish it from the isomers, chaetoglobosins F(ex) , which has an exocyclic double bond on ring B. In negative-ion mode, the McLafferty rearrangement has an important role in the fragmentation pattern of the macrocycle. Some high-abundance radical ions were detected. The radical product ion at m/z 138 might differentiate chaetoglobosins F and penochalasin F, isomers which have very similar structures. In summary, complementary information obtained from fragmentation experiments of [M+H](+) and [M-H](-) precursor ions is especially valuable for rapid identification of chaetoglobosins. The high-abundance radical ions in negative-ion mode are also of scientific interest.
    Rapid Communications in Mass Spectrometry 09/2012; 26(18):2115-22. DOI:10.1002/rcm.6329 · 2.25 Impact Factor
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    ABSTRACT: AimTo investigate the chemical constituents of Isodon xerophilus.Methods The constituents were isolated by various chromatographic methods, and the chemical structures were elucidated on the basis of spectral analyses. Their cytotoxicity was evaluated by the MTT method in 96-well microplates.ResultsTen triterpenes were isolated and identified as oleanolic acid (1), ursolic acid (2), maslinic acid (3), 2α-hydroxyursolic acid (4), hederagenin (5), 3β, 23-dihydroxy-urs-12-en-28-oic acid (6), arjunolic acid (7), asiatic acid (8), 2α, 3α, 24-trihydroxyolean-12-en-28-oic acid (9), and 2α, 3α, 24-trihydroxyurs-12-en-28-oic acid (10). All compounds were tested against three human tumor cell lines, K562, MKN45, and HepG2.Conclusion All of the compounds were isolated from this plant for the first time. The proposed biosynthetic pathway of these triterpenes was discussed. All of the triterpenes showed noncytotoxic activity against the above-mentioned three human tumor cell lines.
    Chinese Journal of Natural Medicines 07/2012; 10(4):307–310. DOI:10.1016/S1875-5364(12)60063-6 · 1.11 Impact Factor
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    ABSTRACT: Calophyline A (1), a novel unprecedented rearranged monoterpenoid indole alkaloid, along with a new natural product N-methyl aspidodasycarpine (2) and six known analogues, was isolated from the trunk barks of Winchia calophylla. The structure of compound 1 was elucidated on the basis of spectroscopic data and then confirmed by a single-crystal X-ray crystallographic analysis. A hypothetical biogenetic pathway for compound 1 was proposed. All isolated compounds were evaluated for their in vitro cytotoxicity against a small panel of human cancer cell lines.
    Organic Letters 06/2012; 14(13):3450-3. DOI:10.1021/ol301400e · 6.36 Impact Factor
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    ABSTRACT: Eight new 19-oxygenated ENT-kaurane diterpenoids were isolated from the aerial parts of Isodon pharicus. Their structures were determined by means of extensive spectroscopic techniques including interpretation of 1D and 2D NMR spectra. Selected compounds were evaluated for their cytotoxicity against NB4, A549, PC-3, MCF-7, and SH-SY5Y cell lines.
    Planta Medica 09/2011; 78(1):52-8. DOI:10.1055/s-0031-1280218 · 2.15 Impact Factor
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    ABSTRACT: A new ent-atisanoid, eriocatisin A (1), six new ent-abietanoids, eriocasins B-E (2-4, 7), 3-acetyleriocasin C (5), and 3β-acetoxyeriocasin D (6), and seven new ent-kauranoids, maoesins A-F (8, 10-14) and 3α-acetoxy-maoesin A (9), together with 21 known compounds, were isolated from the aerial parts of Isodon eriocalyx. The structures of 1-14 were determined by spectroscopic data interpretation. All compounds isolated were evaluated for their in vitro growth inhibitory activity against the HT-29, BEL-7402, and SK-OV-3 human cancer cell lines. Compounds 17, 18, and 20 showed inhibitory effects for all three tumor cell lines used, with IC(50) values in the range 2.1-7.3 μM.
    Journal of Natural Products 10/2010; 73(11):1803-9. DOI:10.1021/np1004328 · 3.80 Impact Factor
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    Li-Mei Li · Yang Liu · Tai Yang · Kai-Bei Yu · Qiang Zou
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    ABSTRACT: In the title solvate, C(30)H(39)NO(5)·CH(4)O {systematic name: 21-acet-oxy-18,21-dihy-droxy-5,6,16,18-tetra-methyl-10-phenyl-6,7-ep-oxy-[11]cytochalasa-13,19-dien-1-one methanol solvate}, the organic mol-ecule exhibits the tetra-cyclic terpenoid skeleton of cytochalasin, consisting of fused five-, six-, three- and 11-membered rings. The five-membered ring adopts an envelope conformation, while the six-membered ring is in a boat conformation. The ep-oxy O atom on the six-membered ring is pointing away from the five-membered ring. An inter-stitial methanol solvent mol-ecule is hydrogen bonded to the cytochalasin mol-ecules and inter-molecular O-H⋯O and N-H⋯O hydrogen bonds connect the mol-ecules into infinite chains along the (10) direction.
    Acta Crystallographica Section E Structure Reports Online 08/2010; 66(Pt 8):o2176-7. DOI:10.1107/S1600536810029600 · 0.35 Impact Factor
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    Journal of Mass Spectrometry 04/2010; 45(4):451-5. DOI:10.1002/jms.1724 · 2.38 Impact Factor
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    ABSTRACT: "Chemical Equation Presented" A new cytotoxic triterpenoid, schinalactone A (1), together with two new biogenetically related compounds, schinalactones B (2) and C (3), has been Isolated from the roots and stems of Schisandra sphenanthera. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 1 and 2 showed significant cytotoxicity against PANC-1 cell lines with IC50 values of 5.9 and 4.1 M, respectively. A plausible biosynthetic pathway of 1 was also postulated
    Organic Letters 02/2010; 12(6):1208-11. DOI:10.1021/ol902974j · 6.36 Impact Factor
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    ABSTRACT: AimTo study the chemical constituents of the aerial parts of Isodon pharicus.
    Chinese Journal of Natural Medicines 11/2009; 7(6). DOI:10.1016/S1875-5364(09)60064-9 · 1.11 Impact Factor

Publication Stats

418 Citations
127.74 Total Impact Points


  • 2007–2015
    • Chengdu Medical College
      Hua-yang, Sichuan, China
  • 2014
    • Yunnan University
      Yün-nan, Yunnan, China
  • 2004–2011
    • Chinese Academy of Sciences
      • • Graduate School
      • • Center for Natural Products
      Peping, Beijing, China
  • 2006–2010
    • Kunming University of Science and Technology
      Yün-nan, Yunnan, China