Stanisław Kalisz

Stabilization of anthocyanin and skullcap flavone complexes – Investigations with computer simulation and experimental methods

We examined the stabilization of anthocyanins with flavones from the practical and theoretical perspective. The influence of addition of skullcap flavones, heating to 50 °C, and 12 day storage time (in the presence and absence of light) on the stability of anthocyanins in honeysuckle concentrates was investigated experimentally. Theoretical study was conducted with molecular dynamics methods in a model system, preceded by simulated annealing and thermalization. By the methods of the computer simulation of the copigmentation process we determined the sites responsible for the stabilization of a cyanidin quinoidal base-baicalin complex. We revealed both direct and water-mediated hydrogen bondings that keep the lamellar stacking structure of these molecules in the bounded form in water medium. The stacking occurs also due to hydrophobic interactions of the rings of both molecules. The experimental part of the study confirmed the effectiveness of anthocyanins stabilization in a concentrate of honeysuckle with the use of skullcap flavones.

The Content of Phenolic Compounds in Leaf Tissues of White (Aesculus hippocastanum L.) and Red Horse Chestnut (Aesculus carea H.) Colonized by the Horse Chestnut Leaf Miner (Cameraria ohridella Deschka & Dimić)

Normally, plant phenolics are secondary metabolites involved in the defense mechanisms of plants against fungal pathogens. Therefore, in this study we attempted to quantify and characterize phenolic compounds in leaves of white and red horse chestnut with leaf miner larvae before and after Cameraria ohridella attack. A total of 17 phenolic compounds belonging to the hydroxycinnamic acid, flavan-3-ols and flavonol groups were identified and quantified in white and red horse chestnut leaf extracts. Significantly decreased concentrations of some phenolic compounds, especially of flavan-3-ols, were observed in infected leaves compared to the non-infected ones. Additionally, a higher content of polyphenolic compounds especially (−)-epicatechin and procyanidins in leaves of red-flowering than in white-flowering horse chestnut may explain their greater resistance to C. ohridella insects.