Accumulation of Reducing Sugars by Small-leaved Linden Flowers (Tilia cordata Miller, 1768) in the Voronezh Region of Russia

Abstract

Introduction. Small-leaved linden flowers are mainly used for aquatic extracts, and their pharmacological benefit is based on water-soluble polysaccharides.Aim. The aim of this study was to investigate the rate of accumulating all reducing sugars in small-leaved linden flowers, collected in agro- and urbo-cenoses of the Voronezh region.Materials and methods. 51 sites were selected for collecting flowers from the small-leaved linden, which is a widespread deciduous tree species in Russia. In order to determine the total level of reducing sugars in the samples, we measured glucose levels using the method described in Pharmacopeia article "Linden Flower". Correlation coefficients were analyzed to examine in detail the effect of the major pollutants (heavy metals and arsenic) on the accumulation of reducing sugars in small-leaved linden flowers.Results and discussion. All analyzed samples of medicinal plant raw materials were benign in terms of their reducing sugar levels. Samples collected in control (protected) areas contained reducing sugar levels 13.31 to 16.89 %, which is 6–8 times more than the lower numerical value established by the Pharmacopoeia article. In the agrocenoses of the region, the concentration of reducing sugars varied from 6.12 to 16.68 %, which is 3–8 times more than the value given in the Pharmacopoeia article. In the urbocenoses of the region, a lower level of reducing sugars was found compared to samples from protected areas (2.35–13.49 %). Correlation coefficients showed a noticeable negative impact of cadmium, chromium, cobalt, copper, zinc, as well as a moderate negative effect of lead and mercury on the accumulation of reducing sugars in the small-leaved linden flowers.Conclusion. The lowest concentrations of reducing sugars were detected in samples harvested along the streets of large cities in the region, and along highways, roads and railways. This suggests that anthropogenic factors might negatively impact the accumulation of reducing sugars in small-leaved linden flowers in these areas. At the same time, it is possible that saccharide complexes might have reacted with heavy metals instead of the complexing agent when levels of reducing sugars in the samples were quantitatively determined. This would have the effect of underrepresenting reducing sugar levels in the raw materials.