title: ¹H-NMR simultaneous identification of health-relevant compounds in propolis extracts.
abstract: BACKGROUND
  Propolis is a resinous substance collected by bees from exudates of different plants that is rich in well-known health-relevant phenolic compounds such as flavonoids and phenolic acids. Propolis extracts are very complex matrices difficult to study. Different analytical methods are usable to analyse propolis extracts and to obtain chemical fingerprint but to our knowledge NMR has not previously been used for this purpose.
  
  
  OBJECTIVE
  This study aims to demonstrate that it is possible to use ¹H-NMR for the simultaneous recognition of phenolic compounds in complex matrices, such as propolis extracts, using appropriate tools for spectra pre-treatment and analysis.
  
  
  METHODS
  In this work 12 typical phenolic propolis compounds (apigenin, chrysin, galangin, kaempferol, quercetin, naringenin, pinocembrin, pinostrobin, caffeic acid, cinnamic acid, p-coumaric acid and ferulic acid) were considered as reference compounds and their presence in samples was verified by HPLC-MS. A simple ¹H-NMR sequence was used to obtain spectra of samples. Spectra were pre-treated by using an appropriate tool for spectra alignment and analysed by using software for the study of spectra originated from complex matrices. Sixty-five propolis samples were used to test the proposed identification procedure.
  
  
  RESULTS
  Ten out of 12 considered compounds were identified as statistically significant in most of the samples.
  
  
  CONCLUSIONS
  This work suggests that it is possible to efficiently use ¹H-NMR, coupled with appropriate spectral analytical tools, for the simultaneous detection of phenolic compounds in complex matrices.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università di Modena e Reggio Emilia, via Campi 183, 41125 Modena, Italy. davide.bertelli@unimore.it
authors.forename: Davide
authors.initials: D
authors.lastname: Bertelli
authors.forename: Giulia
authors.initials: G
authors.lastname: Papotti
authors.forename: Laura
authors.initials: L
authors.lastname: Bortolotti
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Marcazzan
authors.forename: Maria
authors.initials: M
authors.lastname: Plessi
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000032:analysis / Q000302:isolation & purification; D047310:Apigenin / Q000032:analysis / Q000302:isolation & purification; D001516:Bees; D002109:Caffeic Acids / Q000032:analysis / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D002934:Cinnamates / Q000032:analysis / Q000302:isolation & purification; D003373:Coumaric Acids / Q000032:analysis / Q000302:isolation & purification; D044950:Flavanones / Q000032:analysis / Q000302:isolation & purification; D005419:Flavonoids / Q000032:analysis* / Q000302:isolation & purification; D062385:Hydroxybenzoates / Q000032:analysis* / Q000302:isolation & purification; D044949:Kaempferols / Q000032:analysis / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000032:analysis* / Q000302:isolation & purification; D011422:Propionates; D011429:Propolis / Q000032:analysis* / Q000302:isolation & purification; D011794:Quercetin / Q000032:analysis / Q000302:isolation & purification; D015203:Reproducibility of Results
chemical_list: D000890:Anti-Infective Agents; D002109:Caffeic Acids; D002934:Cinnamates; D003373:Coumaric Acids; D044950:Flavanones; D005419:Flavonoids; D062385:Hydroxybenzoates; D044949:Kaempferols; D010936:Plant Extracts; D011422:Propionates; C029010:cinnamic acid; C037032:galangin; C043561:chrysin; C006552:kaempferol; D047310:Apigenin; C016063:pinocembrin; D011429:Propolis; D011794:Quercetin; C004999:ferulic acid; C005273:naringenin; C017616:phenolic acid; C495469:p-coumaric acid; C411294:pinostrobin; C040048:caffeic acid