title: Longan (Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-κB and AP-1 signaling pathways.
abstract: BACKGROUND
  Flower, seed, and fruit of longan (Dimocarpus longan Lour.) have been used in the Traditional Chinese Medicine (TCM) serving as a common herb in relief of swelling which can be applied in cases of inflammatory diseases. However, the scientific evidence related to their effects on inflammation especially the possible cellular and molecular mechanisms of longan need to be clarified.
  
  
  OBJECTIVE
  To evaluate the anti-inflammatory effect of the various parts of longan including flower, seed, and pulp. The mechanisms and molecular targets involved in their effects were also investigated.
  
  
  METHODS
  Different longan extracts were analyzed for their bioactive compounds and evaluated for anti-inflammation. Corilagin, ellagic acid, and gallic acid were detected using HPLC-DAD. In vitro anti-inflammatory effect of longan extracts and their polysaccharides were examined by analyzing nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Expression of the proteins that involved in NO production was detected by Western blot.
  
  
  RESULTS
  Flower extract contained the highest amounts of total phenolics, total flavonoids, proanthocyanidins, corilagin and ellagic acid when compared to seed and pulp extracts. The extracts of different longan parts inhibited LPS-induced NO production with different potency. The highest potency for the inhibition of NO production was shown with flower extract follow by seed and pulp (IC50=128.2, 1127.4, and 1260.2μgmL(-1), respectively). The mechanisms of this anti-NO production were associated with their NO scavenging effect and their decreasing the expression and catalytic activity of an inducible nitric oxide synthase (iNOS). Moreover, these longan extracts suppressed LPS-induced degradation of IκBα and activation of NF-κB, activator protein-1 (AP-1), Akt, and mitogen activated protein kinases (MAPKs).
  
  
  CONCLUSIONS
  These results suggest that the longan extracts possess anti-inflammatory property. Therefore, longan could provide potential dietary supplement for the treatment of inflammatory-related diseases.
authors.affiliation: Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok 10210, Thailand; Applied Biological Sciences Program, Chulabhorn Graduate Institute, Bangkok 10210, Thailand.
authors.forename: Nongluk
authors.initials: N
authors.lastname: Kunworarath
authors.affiliation: Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok 10210, Thailand; Environmental Toxicology Program, Chulabhorn Graduate Institute, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology, Office of Higher Education Commission, Ministry of Education, Bangkok 10400, Thailand.
authors.forename: Nuchanart
authors.initials: N
authors.lastname: Rangkadilok
authors.affiliation: Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok 10210, Thailand.
authors.forename: Tawit
authors.initials: T
authors.lastname: Suriyo
authors.affiliation: Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok 10210, Thailand; Applied Biological Sciences Program, Chulabhorn Graduate Institute, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology, Office of Higher Education Commission, Ministry of Education, Bangkok 10400, Thailand.
authors.forename: Apinya
authors.initials: A
authors.lastname: Thiantanawat
authors.affiliation: Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok 10210, Thailand; Environmental Toxicology Program, Chulabhorn Graduate Institute, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology, Office of Higher Education Commission, Ministry of Education, Bangkok 10400, Thailand. Electronic address: jutamaad@cri.or.th.
authors.forename: Jutamaad
authors.initials: J
authors.lastname: Satayavivad
mesh_terms: D000818:Animals; D035264:Flowers / Q000737:chemistry; D005638:Fruit / Q000737:chemistry; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors* / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology; D000067996:RAW 264.7 Cells; D029631:Sapindaceae / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D015398:Signal Transduction / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000187:drug effects / Q000378:metabolism*
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D010936:Plant Extracts; D011134:Polysaccharides; D018808:Transcription Factor AP-1; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse
keywords: AP-1; Anti-inflammatory effect; Longan (Dimocarpus longan Lour.); NF-κB; Nitric oxide; RAW264.7 macrophage