The presented paper is the first to show thin layer chromatography (TLC) analysis based on eutectic mobile phases (Deep Eutectic Solvents - DES). During the experiment 25 eutectic mixtures were investigated for their chromatographic properties. Most of them belong to the natural deep eutectic solvents (NADES) group. Also, new eutectic liquids based on phenolics and terpenes, not previously employed in analytical practice, were tested. The eutectic liquids were investigated as pure or diluted with solvents used in chromatographic routine: methanol, water, acetone, chloroform or diethyl ether. The analyses were carried out using classic and high performance silica gel plates. The working solution was a mixture of five alkaloids found in genus Chelidonium, namely sanguinarine, coptisine, chelerythrine, chelidonine, and berberine, with UV light detection of 366 nm. This report proves that eutectic TLC is possible and that the eutectic interactions play a crucial role in the separation process. In most of the tested modifications at least partial separation was achieved. The most successful mobile phase, which enabled separation of all the tested alkaloids, was the equimolar mixture of menthol and phenol with a 35% addition of methanol. The system was also effective in separating alkaloids in the real Chelidonium maius extract sample.

Theriac is considered the most popular cure-all multi-ingredient medicine and has been used for more than two millennia. It has also been used as one of the most important anti-epidemic drugs up to the 19th c., treated as an emergency medicine in case of e.g. bubonic plague. Until now, no reliable information regarding the pharmacological effect of the treacle was available, including its possible toxic or narcotic properties. In order to change the state of knowledge in this matter we have selected the Theriac recipe that had been actually used for producing the treacle in 1630, which was confirmed by the official municipal documents of the time. The recipe was written in Latin, with the use of pre-Linnean nomenclature and then apothecary common names, which required translation into the modern scientific language in order to get reliable pharmacological conclusions. The information from historical sources has been compiled with the pharmacological data concerning the most potent compounds, which for the first time made it possible to calculate the amounts of active compounds in the doses taken by then patients. Only two species included in Theriac can be harmful in humans: poppy and sea squill, but in both cases the calculated quantity of morphine and cardiac glycosides, respectively, were below toxic level. There are no indications, both from the historical and pharmacological point of view, for Theriac being toxic or narcotic in patients, when used as prescribed. As for now, the most probable is that the treacle owed its postulated efficacy in the main indications to the placebo effect. Still, the results should be further confirmed by reconstructing the actual Theriac and subjecting it to modern tests and analyses.

Deep eutectic solvents (DES), compared to classic ones, have interesting properties, such as the ability to solubilize compounds differing in polarity or increased dissolution of selected chemical compounds. They also offer specific interactions between the mobile and stationary phases. Those features make them promising solvents in chromatographic techniques, including the use in the separation of complicated samples. The first quantitative analysis with eutectic thin-layer chromatography (TLC) is presented in the paper. As a case study, five alkaloids from Chelidonium maius were selected as target compounds. A wide range of terpene-based DESs was investigated to develop the chromatographic system, both pure and after dilution. Moreover, a novel approach was employed to adjust polarity, involving mixing DESs differing in chromatographic properties. This procedure has proved to be effective. The best results were obtained with a 2:1 (wt/wt) mixture of DESs: camphor + phenol and menthol + limonene, with a 20% addition of methanol. The chromatographic system was validated and checked on the real sample, which made it the first applicable and operational quantitative eutectic TLC system.

Centella asiatica (L.) Urban, Apiaceae, is a medicinal plant, rooted in the Ayurvedic medicine with wide and potent health beneficial activity, and is of great interest to researchers concerning phytotherapy due to its numerous pharmacological activities. In this paper, we have developed a valid thin-layer chromatography (TLC)–densitometric method for the simultaneous determination of the four main C. asiatica active compounds. The additional goal was to achieve the conditions of determination, which would not require spraying with the derivative reagent and subsequent heating ? the factors that greatly deteriorate the validation parameters. In order to do so, we have tested diff erent sorbents (alumina, silica gel, and high-performance thin-layer chromatography [HPTLC] silica gel) and a number of eluents. The best results were obtained with HPTLC silica gel plates eluted with a mixture of CHCl₃–MeOH–H₂O (10:8:2, v/v) and analysed with a densitometer at λ = 202 nm. The chromatographic method was validated for linearity, limit of detection, limit of quantification, repeatability, intermediate precision, and recovery.