Content of phenolic compounds and flavonoids in morphological parts of Melilotus officinalis

The aim of the work was to study the content of phenolic compounds and flavonoids in the extracts from different morphological parts of Melilotus officinalis. In this study, the conditions of ultrasonic extraction were optimized. An increase in temperature contributes to an increase in the phenolic compound content regardless of the particle size of the plant material. The temperature had a greater effect on the fraction with a particle size of 1.0 to 2.0 mm, since the yield of phenolic compounds at an extraction temperature of 70 ˚C is 2 times higher compared to extraction at 20 ˚C and is 8.4 mg/g. When using the raw material to extractant ratio of 1:30 and 1:50, an increase in the phenol content is observed with an extraction time of up to 20 min. Carrying out extraction with a ratio of 1:100 for longer than 5 minutes is not practical. Considering the optimized parameters, extracts were obtained from various morphological parts of M. officinalis using an ultrasonic bath with ethyl alcohol as an extractant in various ratios with water, and the concentration of phenolic compounds and flavonoids was determined. The content of phenolic compounds is highest in the flowers and leaves of sweet clover and reaches 22.2 mg/g. The highest content of flavonoids was found in the flowers of the plant during extraction with 50% ethyl alcohol and is 1.21 mg/g. In sweet clover seeds, the content of phenols fluctuates from 7.0 to 10.9 mg/g, and with an increase in the proportion of alcohol in the extractant, their concentration decreases. The content of phenols in the stems and roots increases with an increase in the alcohol concentration to 50 % and is 6.3 and 5.3 mg/g, respectively. However, for maximum extraction of phenols from the stems, ethyl alcohol with a concentration of 30 % can be used.

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