LC–QQQ and LC–QTOF MS methods for comprehensive detection of potential allergens in various propolis extracts

Propolis is a highly complex matrix, in which phenolics are the mostly analyzed constituents. However, detailed propolis analysis is often lacking due to the high price of the commercially available phenolic standards and the lack of standards of phenols that are causing allergic reaction to propolis. Therefore, it is crucial to develop methods for detection and quantification of these constituents so that, afterwards, propolis extractions can be adjusted to the desired final application. Developed mass spectrometry-based methods were used for the quantification of 25 known phenols as well as for the identification and quantification of 27 additional phenolic derivatives, for which the standards are not readily available. We demonstrated that these newly discovered phenolic derivatives may have a high share in propolis, among which hydroxycinnamic are the most important ones as they are responsible for allergenic properties of propolis-based products. To track the changes in hydroxycinnamic acid derivatives, different propolis extract were prepared and analyzed with developed protocol. All obtained data were processed using chemometric tools to gain insight into allergens content in different propolis extracts. The presented protocol is in line with the food and pharma industry’s growing needs for a comprehensive knowledge on the propolis composition, as it is used in a variety of functional and medicinal products. Knowing that some phenolic components may exert unwanted side effects, a precise selection of a fraction of compounds from propolis is essential for the development of safe-end products.