Degradation of anthocyanins involves scission of the flavonoid skeleton yielding 2,4,6-trihydroxybenzaldehyde (phloroglucinaldehyde, PGA) and a phenolic acid. However, the process is not finished with the formation of PGA, as the consequent condensation of two PGA molecules providing colored hydroxylated anthraquinones was observed for the first time. This process was studied using a combination of preparative column chromatography, nuclear magnetic resonance, liquid chromatography/high resolution tandem mass spectrometry (LC/HRMS2), and quantum calculations using density functional theory. 1,3,5,7-tetrahydroxyanthraquinone (anthrachrysone) and its isomers were found to rise during heating (95 °C) in a buffered PGA model solution (phosphate buffer, pH 7). These compounds were detected in heated red wine after an increase of its pH value. The concentration of the identified anthrachrysone in the red wine reached 0.01 mg·L−1. Presence of those compounds could therefore indicate involvement of certain steps in the processing of plant materials rich in anthocyanins (e.g., utilization of a higher temperature and/or reduction of acidity) or long-term transformation of anthocyanins (potentially, for instance, in archaeological findings such as wine or fruit residues). Additionally, measurement of wine–soil suspensions proved an increase of their pH to the values suitable for anthocyanin cleavage (neutral to slightly alkaline; reached using soil from archaeologically well-known Bull Rock Cave). Although not found in artificially prepared samples (imitations) or authentic materials so far, according to our results the above mentioned conditions are suitable for the formation of tetrahydroxylated anthraquinone derivatives and their monitoring would be beneficial.
AUS DER NÄH E ODER AUS DER F ER N E?Zu den hallstattzeitlichen Funden vom östlichen Typ aus Mähren 1 a n i t a k o Z u B o vá -m a r t i n g o l e c From Nearby or Faraway? To the Hallstatt Findings of the Eastern Type from Moravia. in the present study, we deal with relatively numerous findings of eastern type from Moravia, which are dated to the whole stage HD. Providing a more complex overview of those findings was at the centre of our interest, focused mainly on their cultural-spatial analysis and possible interpretations of their occurrence in Moravia. Four groups of their origin were identified. The analysis of these findings did not confirm the claims that their occurrence in Moravia is connected with the collapse of local groups of the East Hallstatt culture.
Research on the Hallstatt and La Tène Periods in Bohemia and Moravia covers a number of important topics. So far out of the main interest is the increasing quantity of foreign artefacts which generally belong to the Vekerzug culture (or through its spreading objects of other Eastern cultures). The authors of this paper believe that their systematic evaluation is essential for progress in this area of research. The volume of individual artefacts and associated contexts is constantly increasing. This is due to systematic research conducted by archaeological institutions, extensive development-led excavations (construction of highways, expansion of industrial zones, etc.), and detector survey carried out by amateurs, which has been monitored with partial success. Systematic scientific research by specialists, however, still lags behind. This paper attempts to partly fill this gap.
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