Extraction of Biologically Active Substances from the Bark and Leaves of Trees of the Salicaceae Family

The process of extraction of biologically active substances from non-woody parts of trees (bark and leaves) of willow and aspen is described in the article. The instrumentation for extracting salicin and quercetin from the bark and leaves of trees of the Salicaceae family is presented. A method for experimental research and obtaining of biologically active substances is presented. It has been found that an increase in the extractant consumption from 20 to 100 l/min at the same temperature (75 °С) and 95 % impregnation leads to a 2-fold acceleration of the process. Local temperature changes across the layers of the material have been described. A slight lag in heating of subsequent layers of the material by 1–2 min has been determined, which is due to the thermal inertia of the material and the peculiarities of heat transfer within the layer. It takes 7 min to achieve full heating. A kinetic curve of the concentration of extracted biologically active substances in the extract has been constructed. The resulting dependencies and comparative data allow us to recommend rational modes of extraction of biologically active substances from the bark and leaves of willow and aspen trees. According to the results of the research, the optimal temperature for quercetin extraction has been recommended to be 50 °С. It has also been found that increasing the temperature to 75 °С leads to a noticeable increase in the yield of salicin. Moreover, it has been revealed that the largest amount of quercetin is found in aspen (1.4 %), with 11.4 % more quercetin in the leaves than in the bark; the main amount of salicin is found in the bark of both species, but in willow bark there is an excess of 35 %; the rational solvent concentration is 60 %; the duration of extraction is 40–45 min.