Chemical study of the composition and quantitative analysis of hydroxycinnamic acids in experimental samples of propolis

Abstract

Background and Objective: This article presents the results of the determination of hydroxycinnamic acids in 6 experimental propolis samples. Using reversed-phase high-performance liquid chromatography in a gradient elution mode is able to identify hydroxyl and cinnamic acids by comparing retention times of analytes, the standard samples and the corresponding acids according to the results of diode-matrix detection. Method: Six prototype propolis samples from different regions of Russia were taken as research objects. From the experiment, samples were prepared extracts by 80% ethanol extraction, according to the traditional production scheme of tinctures in a ratio of 1:10. It was found that the composition of propolis has a stable set hydroxycinnamic acids comprising about 6 components: Trans-p-coumaric, ferulic, isoferulic, caffeic, 3,4-dimethyl caffeic and cinnamic acids. The internal normalization method calculates the specific weight of each of the components within the specified group. Results: It has been established that about 90% of all oxycinnamic acids are trans-para-coumaric, ferulic, and caffeic acids with a predominance of the first. The quantitative content of the dominant hydroxycinnamic acids in propolis prototypes was determined by the absolute calibration method. The content of trans-para-coumaric acid was in the range 1.43-2.1%; ferulic acid - 0.93-1.6%; and caffeic acid - 0.193-0.44%. Conclusion: The results of the conducted experiments make it possible to recommend an assessment of the quality of propolis by any of the dominant acids.