title: Identification of a naturally occurring retinoid X receptor agonist from Brazilian green propolis.
abstract: BACKGROUND
  Brazilian green propolis (BGP), a resinous substance produced from Baccharis dracunculifolia by Africanized honey bees (Apis mellifera), is used as a folk medicine. Our present study explores the retinoid X receptor (RXR) agonistic activity of BGP and the identification of an RXR agonist in its extract.
  
  
  METHODS
  RXRα agonistic activity was evaluated using a luciferase reporter gene assay. Isolation of the RXRα agonist from the ethanolic extract of BGP was performed using successive silica gel and a reversed phase column chromatography. The interaction between the isolated RXRα agonist and RXRα protein was predicted by a receptor-ligand docking simulation. The nuclear receptor (NR) cofactor assay was used to estimate whether the isolated RXRα agonist bound to various NRs, including RXRs and peroxisome proliferator-activated receptors (PPARs). We further examined its effect on adipogenesis in 3T3-L1 fibroblasts.
  
  
  RESULTS
  We identified drupanin as an RXRα agonist with an EC50 value of 4.8 ± 1.0 μM. Drupanin activated three RXR subtypes by a similar amount and activated PPARγ moderately. Additionally, drupanin induced adipogenesis and elevated aP2 mRNA levels in 3T3-L1 fibroblasts.
  
  
  CONCLUSIONS
  Drupanin, a component of BGP, is a novel RXR agonist with slight PPARγ agonistic activity.
  
  
  CONCLUSIONS
  This study revealed for the first time that BGP activates RXR and drupanin is an RXR agonist in its extract.
authors: Laboratory of Natural Resources, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
authors: Ken-Ichi
authors: K
authors: Nakashima
authors: Laboratory of Natural Resources, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
authors: Tohru
authors: T
authors: Murakami
authors: Laboratory of Natural Resources, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
authors: Hiroki
authors: H
authors: Tanabe
authors: Laboratory of Natural Resources, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan. Electronic address: minoue@aichi-gakuin.ac.jp.
authors: Makoto
authors: M
authors: Inoue
mesh_terms: D041721:3T3-L1 Cells; D050156:Adipogenesis / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001516:Bees; D001938:Brazil; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D062105:Molecular Docking Simulation; D047495:PPAR gamma / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D011429:Propolis / Q000737:chemistry / Q000494:pharmacology; D047490:Retinoid X Receptor alpha / Q000819:agonists* / Q000235:genetics / Q000378:metabolism
chemical_list: D047495:PPAR gamma; D047490:Retinoid X Receptor alpha; D011429:Propolis
keywords: Bioactive natural compound; Drupanin; Peroxisome proliferator-activated receptor; Propolis; Retinoid X receptor