1 H‐NMR Simultaneous Identification of Health‐Relevant Compounds in Propolis Extracts

• Published in: Phytochemical analysis Vol. 23; no. 3; pp. 260 - 266
• Main Authors: Bertelli, Davide, Papotti, Giulia, Bortolotti, Laura, Marcazzan, Gian Luigi, Plessi, Maria
• Format: Journal Article
• Language: English
• Published: 01.05.2012
• ISSN: 0958-0344; 1099-1565
• DOI: 10.1002/pca.1352

ABSTRACT Introduction 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 1 H‐NMR for the simultaneous recognition of phenolic compounds in complex matrices, such as propolis extracts, using appropriate tools for spectra pre‐treatment and analysis. Methodology 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 1 H‐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. Conclusion This work suggests that it is possible to efficiently use 1 H‐NMR, coupled with appropriate spectral analytical tools, for the simultaneous detection of phenolic compounds in complex matrices. Copyright © 2011 John Wiley & Sons, Ltd. This work shows the use of NMR for the simultaneous recognition of phenolic compounds in propolis extracts. Twelve typical propolis compounds (apigenin, chrysin, galangin, kaempferol, quercetin, naringenin, pinocembrin, pinostrobin, caffeic acid, cinnamic acid, p‐coumaric acid, ferulic acid) and 65 samples were considered. Ten compounds were identified as statistically significant. The results suggest that it is possible to use the NMR, coupled with appropriate spectral analytical tools, for the simultaneous detection of phenolic compounds in complex matrices.