title: Activity-guided isolation of NF-κB inhibitors and PPARγ agonists from the root bark of Lycium chinense Miller.
abstract: BACKGROUND
  The root bark of Lycium chinense Miller, Lycii radicis cortex, has been used in traditional Chinese medicine (TCM) to treat different inflammation-related symptoms, such as diabetes mellitus. The pro-inflammatory transcription factor nuclear factor kappa B (NF-κB) is a key regulator of inflammation, while the transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) is a key modulator of genes involved in diabetes development. To identify putative active compound(s) from Lycii radicis cortex inhibiting NF-κB or activating PPARγ.
  
  
  METHODS
  Using activity-guided fractionation, six extracts with different polarity, isolated fractions, and purified compounds from Lycii radicis cortex were tested for NF-κB inhibition and PPARγ activation in vitro. The structure of the purified compounds was elucidated by NMR and MS techniques.
  
  
  RESULTS
  The ethyl acetate extract and the methanol extract of Lycii radicis cortex suppressed tumor necrosis factor alpha (TNF-α)-induced activation of NF-κB, while the dichloromethane extract activated PPARγ. Nine phenolic amide analogues, including trans-N-(p-coumaroyl)tyramine (1), trans-N-feruloyltyramine (2), trans-N-caffeoyltyramine (3), dihydro-N-caffeoyltyramine (4), three neolignanamides (5-7), and two lignanamide (8, 9), were isolated and their inhibitory potential on NF-κB was determined (1-4 were also contained in water decoction). Two of the nine isolated phenolic amides inhibited TNF-α-induced NF-κB activation. Trans-N-caffeoyltyramine was verified as the key component responsible for the NF-κB inhibition with an IC50 of 18.4μM in our cell-based test system. Activation of PPARγ was attributed to a palmitic-acid enriched fraction which displayed concentration-dependent effect ablated upon co-treatment with the PPARγ antagonist T0070907.
  
  
  CONCLUSIONS
  Phenolic amides were confirmed as main components from Lycii radicis cortex responsible for NF-κB inhibition. Fatty acids were identified as the major plant constituent responsible for the PPARγ activation. Structure-activity relationship analysis suggests that the NF-κB inhibitory activity of trans-N-caffeoyltyramine may be attributed to its Michael acceptor-type structure (α,β-unsaturated carbonyl group). The data of this study contribute to a better understanding of the molecular mechanism of action of Lycii radicis cortex extracts in the context of inflammation.
authors: School of Sciences, Central South University of Forestry and Technology, 498 South Shaoshan Road, 410004 Changsha, Hunan, PR China; Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Hunan University of Chinese Medicine, Hanpu S&E District, 410208 Changsha, Hunan, PR China.
authors: Lian-Wu
authors: LW
authors: Xie
authors: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Atanas G
authors: AG
authors: Atanasov
authors: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, 201203 Shanghai, PR China.
authors: De-An
authors: DA
authors: Guo
authors: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Clemens
authors: C
authors: Malainer
authors: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, 201203 Shanghai, PR China.
authors: Jing-Xian
authors: JX
authors: Zhang
authors: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Martin
authors: M
authors: Zehl
authors: Shanghai Research Center for Modernization of Traditional Chinese Medicine, National Engineering Laboratory for TCM Standardization Technology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, 201203 Shanghai, PR China.
authors: Shu-Hong
authors: SH
authors: Guan
authors: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Elke H
authors: EH
authors: Heiss
authors: Department of Medicinal Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Ernst
authors: E
authors: Urban
authors: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Verena M
authors: VM
authors: Dirsch
authors: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. Electronic address: brigitte.kopp@univie.ac.at.
authors: Brigitte
authors: B
authors: Kopp
mesh_terms: D000577:Amides / Q000302:isolation & purification / Q000494:pharmacology; D005227:Fatty Acids / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D032305:Lycium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008516:Medicine, Chinese Traditional; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D047495:PPAR gamma / Q000819:agonists*; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology; D024301:Plant Bark; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D018517:Plant Roots; D013329:Structure-Activity Relationship; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage
chemical_list: D000577:Amides; D005227:Fatty Acids; D016328:NF-kappa B; D047495:PPAR gamma; D010636:Phenols; D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha
keywords: CHEMBL2337115 (PubChem CID: 71719510); CHEMBL2337117 (PubChem CID: 71524310); CHEMBL2337118 (PubChem CID: 71524309); CHEMBL2337119 (PubChem CID: 71524308); CHEMBL2337120 (PubChem CID: 71524307); Dihydro-N-caffeoyltyramine (PubChem CID: 16119668); Fatty acids; Lycii Radicis Cortex; Lycium chinense Miller; NF-κB; PPARγ; Phenolic amides; Trans-N-(p-coumaroyl)tyramine (PubChem CID: 5372945); Trans-N-caffeoyltyramine (PubChem CID: 9994897); Trans-N-feruloyltyramine (PubChem CID: 5280537)