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Evidence-Based Complementary and Alternative Medicine
Volume 2015 (2015), Article ID 595393, 9 pages
http://dx.doi.org/10.1155/2015/595393
Research Article

Effect of Ethanol/Water Solvents on Phenolic Profiles and Antioxidant Properties of Beijing Propolis Extracts

1Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
2College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
3National Research Center of Bee Product Processing, Ministry of Agriculture, Beijing 100093, China

Received 27 April 2015; Revised 21 July 2015; Accepted 29 July 2015

Academic Editor: Marie-Geneviève Dijoux-Franca

Copyright © 2015 Chunli Sun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Propolis is a natural substance known to be beneficial for human health and used as a folk medicine in many parts of the world. In this study, phenolic profiles and antioxidant properties of Beijing propolis extracted by different ethanol/water solvents were analyzed. Our results reveal that phenolic compounds and antioxidant properties of propolis extracts were significantly dependent on the concentration of ethanol/water solvents. Totally, 29 phenolic compounds were identified: 12 phenolic acids, 13 flavonoids, and 4 phenolic acid esters. In particular, 75 wt.% ethanol/water solvent may be the best for the highest extraction yield and the strongest antioxidant properties. Caffeic acid, benzyl caffeate, phenethyl caffeate, 5-methoxy pinobanksin, pinobanksin, pinocembrin, pinobanksin-3-O-acetate, chrysin, and galangin were the characteristic compounds of Beijing propolis, and these compounds seem to verify that Beijing propolis may be poplar-type propolis. In addition, the presence of high level of pinobanksin-3-O-acetate in Chinese propolis may be a novel finding, representing one-third of all phenolics.