title: Identification of active compounds from Caesalpinia sappan L. extracts suppressing IL-6 production in RAW 264.7 cells by PLS.
abstract: BACKGROUND
  Caesalpinia sappan L. is distributed in Southeast Asia and also used as herbal medicine for the treatment of various diseases such as burning sensations, leprosy, dysentery, osteoarthritis and rheumatoid arthritis (RA). The overproduction of IL-6 plays an important role in the prognosis of RA, but the active compounds from the extracts of Caesalpinia sappan L. suppressing IL-6 production remain unknown.
  
  
  OBJECTIVE
  Identifying the main active compounds of Caesalpinia sappan L. extracts inhibiting the IL-6 production in LPS-stimulated RAW 264.7 cells by partial least squares (PLS).
  
  
  METHODS
  Sixty-four samples with different proportions of compounds were prepared from Caesalpinia sappan L. by supercritical CO2 fluid extraction (SCFE) and refluxing. Each of 64 samples was applied to RAW 264.7 cells with LPS to evaluate whether IL-6 production by LPS is affected by addition of each sample. The IL-6 production in medium was determined by ELISA and the inhibitory activity of each sample was analyzed. In addition, the fingerprints of these 64 samples were also established by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-MS). We used the PLS, a simplified method, to evaluate the results from IL-6 production and fingerprints.
  
  
  RESULTS
  Each of 64 samples markedly suppressed LPS-induced IL-6 production in RAW cells. The fingerprints by UPLC-MS clearly revealed variations among 64 samples produced in different extract conditions. The PLS analysis with IL-6 production and fingerprints by UPLC-MS suggested that the peaks 71, 93, 150, 157, 168 have more influence on the inhibitory activity of Caesalpinia sappan L. extracts. The peaks 71, 93, 150 are likely representing sappanone A, protosappanin E and neoprotosappanin, respectively. The peaks 157 and 168 are still at large.
  
  
  CONCLUSIONS
  This is the first report that sappanone A, protosappanin E, neoprotosappanin and two unidentified compounds can be considered as possible active compounds that might inhibit IL-6 production. Further studies are needed to confirm the effectiveness of these five compounds on IL-6 production and possible mechanism.
authors.affiliation: Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University-Daqing, Daqing 163319, China.
authors.forename: Ming-Juan
authors.initials: MJ
authors.lastname: Chu
authors.forename: You-Zhi
authors.initials: YZ
authors.lastname: Wang
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Itagaki
authors.forename: Hong-Xing
authors.initials: HX
authors.lastname: Ma
authors.forename: Ping
authors.initials: P
authors.lastname: Xin
authors.forename: Xue-Gang
authors.initials: XG
authors.lastname: Zhou
authors.forename: Guo-You
authors.initials: GY
authors.lastname: Chen
authors.forename: Sen
authors.initials: S
authors.lastname: Li
authors.forename: Shi-Qin
authors.initials: SQ
authors.lastname: Sun
mesh_terms: D000818:Animals; D029911:Caesalpinia; D002460:Cell Line; D000431:Ethanol / Q000737:chemistry; D015850:Interleukin-6 / Q000378:metabolism; D016018:Least-Squares Analysis; D008070:Lipopolysaccharides; D051379:Mice; D010936:Plant Extracts / Q000032:analysis / Q000494:pharmacology*; D012997:Solvents / Q000737:chemistry; D014934:Wood / Q000737:chemistry; D000093242:Interleukin-6 Inhibitors
chemical_list: D000431:Ethanol; D015850:Interleukin-6; D008070:Lipopolysaccharides; D010936:Plant Extracts; D012997:Solvents; D000093242:Interleukin-6 Inhibitors