Özet:

The aim of the work. The studying of the flavonoids profile of the mulberry white leaves alcohol extracts and the sugar-lowering effect of its dry extract depending on the ethanol concentration in the extractant. Materials and Methods. Material for research – liquid extracts obtained by fractional maceration of white mulberry leaves with alcoholic solutions containing 10–95 % (v/v) of the ethanol, the ratio of raw material to extractant 1:10, multiplicity extraction – 5, one extraction duration – 24 hours; the extracts were concentrated in a rotary evaporator and dried at 45–50 ° C. The study of the flavonoids profile was performed by chromatographic methods, the quantitative content of flavonoids was determined by spectrophotometric method, the content of the dry residue – by gravimetric method. Results and Discussion. Qualitative studies of alcoholic extracts of the white mulberry leaves, carried out by TLC and HPLC, allowed us to identify the rutin, isoquercitrin, kaempferol-3-O-glucoside and quercitrin (small amount). The qualitative composition is practically unchanged due to the flavonoids glycosides solubility in a wide range of ethanol concentrations. It was established, that the increase of ethanol content in the extractant from 40 to 80 % (v/v), leads to increased of the flavonoids extraction. Extractants containing 40–80 % (v/v) of the ethanol allow to obtain liquid extracts with almost the same dry residue (2 %). Extractants with the ethanol content of 70–80 % (v/v) provide the highest extraction of flavonoids under other identical conditions (1.17–1.24 mg / ml in terms of rutin, spectrophotometric method). The dry extracts obtained with the extractants with the ethanol content of 60–90 % (v/v) showed the ability to significantly reduce glucose level in the blood of animals during “glucose load”. Conclusions. The chromatographic profile of the alcoholic extracts from the mulberry white leaves contains rutin, isoquercitrin, kaempferol-3-O-glucoside and quercitrin. With increasing of the ethanol concentration in the extractant, the content of flavonoids increases, and the extractants with the ethanol content of 70–80 % (v/v) are the most effective for the extraction of flavonoids. The dry extracts obtained on the investigated extracts basis the significantly reduce the glucose level in the blood of the animals in the ‘glucose load” experiment.

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