title: A PPARγ ligand present in Actinidia fruit (Actinidia chrysantha) is identified as dilinolenoyl galactosyl glycerol.
abstract: Activity-guided fractionation of Actinidia fruit species, including Kiwifruit, has identified DLGG (dilinolenoyl galactosyl glycerol) as a potent PPARγ (peroxisome-proliferator-activated receptor γ) ligand. DLGG is a type of MGDG (monogalactosyl diacylglycerol) and is present in all chloroplasts, and therefore all green fruits and vegetables. PPARγ is a ligand-activated transcription factor that regulates glucose metabolism and inflammation. An ethyl acetate extract of Actinidia chrysantha was fractionated by HPLC and the PPARγ-binding activity was detected by FP (fluorescence polarization). Linoleic and α-linolenic acids in A. chrysantha were readily detected as PPARγ ligands. Slow-binding PPARγ ligands were detected in several hydrophobic fractions. High-resolution MS identified DLGG as one of these ligands and confirmed that its binding is non-covalent. DLGG is a slow-binding PPARγ ligand with an IC50 of 1.64 μM, ±0.093 achieved after 45 min equilibration. DLGG is the first example of a form of DAG (diacylglycerol) that is a PPARγ ligand. In addition, DLGG is the first reported glycolipid ligand for PPARγ and also the first non-covalent, slow-binding PPARγ ligand.
authors.affiliation: Food Innovation, the New Zealand Institute for Plant and Food Research Ltd, Private Bag 11 600, Palmerston North 4442, New Zealand. harry.martin@plantandfood.com
authors.forename: Harry
authors.initials: H
authors.lastname: Martin
authors.forename: Tony K
authors.initials: TK
authors.lastname: McGhie
authors.forename: Rona C M
authors.initials: RC
authors.lastname: Lunken
mesh_terms: D029042:Actinidia / Q000737:chemistry / Q000378:metabolism*; D005638:Fruit / Q000737:chemistry / Q000378:metabolism*; D005697:Galactosides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D047495:PPAR gamma / Q000378:metabolism*; D011485:Protein Binding; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D005697:Galactosides; D047495:PPAR gamma; C025100:isofloridoside
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