Insight into the influence of natural deep eutectic solvents on the extraction of phenolic compounds from poplar type propolis: Composition and in vitro biological activity
Boryana Trusheva,
Hristo Petkov,
Ralitsa Chimshirova,
Milena Popova,
Lyudmila Dimitrova,
Maya M. Zaharieva,
Yana Ilieva,
Bela Vasileva,
Iva Tsvetkova,
Hristo Najdenski,
George Miloshev,
Milena Georgieva,
Vassya Bankova
Affiliations
Boryana Trusheva
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113, Sofia, Bulgaria; Corresponding author. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Str., Bl. 9, 1113, Sofia, Bulgaria.
Hristo Petkov
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113, Sofia, Bulgaria
Ralitsa Chimshirova
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113, Sofia, Bulgaria
Milena Popova
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113, Sofia, Bulgaria
Lyudmila Dimitrova
The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 26, 1113, Sofia, Bulgaria
Maya M. Zaharieva
The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 26, 1113, Sofia, Bulgaria
Yana Ilieva
The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 26, 1113, Sofia, Bulgaria
Bela Vasileva
Institute of Molecular Biology “Roumen Tsanev”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113, Sofia, Bulgaria
Iva Tsvetkova
The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 26, 1113, Sofia, Bulgaria
Hristo Najdenski
The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 26, 1113, Sofia, Bulgaria
George Miloshev
Institute of Molecular Biology “Roumen Tsanev”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113, Sofia, Bulgaria
Milena Georgieva
Institute of Molecular Biology “Roumen Tsanev”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113, Sofia, Bulgaria
Vassya Bankova
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113, Sofia, Bulgaria
Natural deep eutectic solvents (NADESs) have been considered promising to replace traditional volatile and toxic organic solvents for the extraction of biologically active substances from natural sources. This work applied an efficient and ethanol-exclusion strategy for extraction of phenolic compounds from poplar type propolis using five known NADESs (lactic acid:1,2-propanediol 1:1, lactic acid:fructose 5:1, choline chloride:1,2-propanediol 1:3, choline chloride:1,2-propanediol:water 1:1:1 and betaine:malic acid:water 1:1:6). The selected NADESs' extractability was evaluated by measuring the concentrations of total phenolics and total flavones and flavonols in the propolis extracts obtained, which qualitative chemical composition was further determined in detail by gas chromatography-mass spectrometry (GC-MS) analysis. It demonstrated that the chemical profiles of NADES and 70% ethanolic propolis extracts are similar. To expand the knowledge about the role of the applied solvents in the poplar propolis extraction process, the in vitro antimicrobial, cytotoxic and genotoxic activity of both NADESs and liquid NADES extracts were evaluated. The results revealed that the use of the selected NADESs as an extraction media for phenolic compounds from poplar propolis not only delivered a good extraction yield in some cases, but generally led to the preservation of propolis extracts' biological activity and even to the enhancement of their antimicrobial effect in comparison with the hydroethanolic one. Besides, the tested NADESs except for lactic acid:fructose and betaine:malic acid:water exerted low to negligible toxicity against normal cells treated and apart from lactic acid:fructose the remaining solvents demonstrated concentration-dependent moderate to subtle genotoxicity. There is a probability that not the supramolecular structure of the NADESs, but their components, played a key role for the observed biological effects. The present study has demonstrated an alternative approach for extracting the biologically active complex from poplar type propolis using NADESs, which could be useful for further pharmaceutical and cosmeceutical applications.
