LC-MS/MS analysis of red and green Türkiye propolis and determination of correlations between certain phenolic compounds

The honey bees (<i>Apis mellifera</i>) collect propolis from the resins of the plants around the hives for various purposes. The chemical structure of propolis contains many active ingredients, including phenolic compounds. Plants, altitude, season, or climatic zone are the most important factors influencing these components. The active ingredients in propolis influence the color of the propolis as well as the composition of the propolis. The aim of this study was to investigate and compare the content of 28 phenolic compounds of red and green propolis collected from Türkiye utilizing LC-MS/MS analysis. For this purpose, 318 propolis samples were collected from apiaries. Twenty-nine red and green samples were separated and analyzed for phenolic compounds. It was found that the seasons significantly affected the color changes of propolis. While most of the red propolis was detected in the spring, most of the green propolis was detected in the autumn. Furthermore, it was determined that the color changes of propolis produced statistically significant differences in terms of phenolic components, even in the colors within themselves. In addition, the availability and amount of phenolic compounds in propolis were found to have statistically significant negative and positive relationships among themselves. In conclusion, it was noticed that the change in color of propolis can significantly alter its phenolic composition, which can affect its average chemical structure.