Abstract
Propolis is a complex mixture of natural compounds, including resinous terpenoids, flavonoids, aromatic acids, and essential oils, and has strong antimicrobial, antifungal, and antioxidant properties. The chemical composition of propolis determines its properties and strongly depends on a wide variety of different plant sources, as well as other climate and environmental parameters. In order to determine the main compounds, in this study, we applied an integrated analysis of propolis by thin-layer chromatography (TLC) to characterize and compare the phytochemical profiles of selected bioactive materials in raw propolis. TLC served as a rapid, cost-effective, and highly visual technique to separate and identify key constituents, including terpenoids, flavonoids, and phenolic compounds in propolis, without a need for further precleaning steps after performing ultrasonic extraction. Complementary methods, such as FTIR spectroscopy, were employed to validate and quantify the active components detected through TLC screening. In addition, the UV-VIS method revealed the solubility of raw propolis in different solvents, after testing for coffee ring effects. The results confirmed that the complex structure of the raw sample can be more thoroughly revealed by two-dimensional TLC, which enables not only rapid and verifiable qualitative results but also detection of overlapping spots. Moreover, by comparing the results with data from the literature, not only can particular chemical compounds be efficiently determined by TLC but also the regional origin of samples.