Standardization of Propolis, is it Possible?

Propolis is a resinous product with a complex structure. Standardization of raw propolis is difficult because the composition of raw propolis depends on many factors such as flora of the area, harvesting season, collection style and bee strain. However, standardization of propolis extract prepared with ethanol rather than raw propolis could be achievable. In this study, basic components of ethanol extract prepared with propolis samples collected from 13 different localities of Anatolia were investigated. Basic parameters such as wax, balsam, total polyphenol, flavonoid and tannin content of extracts were determined. Phenolic composition of the extracts were also identified by using HPLC-UV with fourteen standard phenolic compounds. Results showed that all parameters were found to differ in terms of the flora of the area propolis collected but total polyphenol, flavonoid and tannin content were found to be important criteria for the standardization of propolis extracts. Moreover, phenolic acids like caffeic acid, p-coumaric acid and ferulic acid were determined as characteristic compounds for qualitatively describing ethanol extracts prepared by using Anatolian propolis. As a result, it can be concluded that although absolute standardization of propolis extract is not possible nevertheless total polyphenol and flavonoid contents are important criteria in terms of standardization of propolis ethanol extracts. In conclusion, ethanol extracts prepared with Anatolian propolis should contain caffeic acid, ferulic acid, p-coumaric acid, t-cinnamic acid and luteolin or their derivatives using this standardized method