title: Brazilian red propolis: unreported substances, antioxidant and antimicrobial activities.
abstract: BACKGROUND
  Chloroform, ethyl acetate and methanol extracts of a sample of red propolis from the state of Alagoas (northeast Brazil) were analyzed by gas chromatography-mass spectrometry and high-performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry. Antimicrobial and antioxidant activities were also obtained.
  
  
  RESULTS
  The propolis sample contained low content of narigenin-8-C-hexoside, this being the first report of a C-glycoside in propolis. The main constituent found was characterized as 3,4,2',3'-tetrahydroxychalcone. Other important constituents were the chalcone isoliquiritigenin, the isoflavans (3S)-vestitol, (3S)-7-O-methylvestitol, the pterocarpan medicarpin, the phenylpropenes trans-anethol, methyl eugenol, elimicin, methoxyeugenol and cis-asarone, and the triterpenic alcohols lupeol and α- and β- amyrins. The methanol extract exhibited high antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl and β-carotene/linoleic acid assay methods, and antimicrobial activity toward Gram-positive and Gram-negative bacteria.
  
  
  CONCLUSIONS
  Structures are suggested for new substances never before seen in any kind of propolis. This is the first report of 3,4,2',3'-tetrahydroxychalcone and a flavone C-glycoside in a propolis sample.
authors: Institute of Biosciences, Botany Department, University of São Paulo, São Paulo, SP, Brazil. adnerighi@gmail.com
authors: Adne A
authors: AA
authors: Righi
authors: Thiago R
authors: TR
authors: Alves
authors: Giuseppina
authors: G
authors: Negri
authors: Lucas M
authors: LM
authors: Marques
authors: Henrique
authors: H
authors: Breyer
authors: Antonio
authors: A
authors: Salatino