Poster presentation
167
CHEMICAL STRUCTURE OF THE POLYPHENOL
COMPOSITION OF THE LEAVES OF PONTIAN HAWTHORN
Crataegus pontica
K.V. Raimova, N.G. Abdulladzhanovа, A.D. Matchanov
Institute of Bioorganic Chemistry named after acad. A.S. Sadykov
Academy of Sciences of the Republic of Uzbekistan, Mirzo Ulugbek str., 83,
Tashkent, 100125 (Republic of Uzbekistan).
The chemical composition (polyphenols) of the leaves of the plant
Crataegus pontica
K. Koch has been studied. The process of isolating polyphenols from plant raw
materials includes several stages: extraction of raw materials, processing of the extract
with organic solvents, evaporation, precipitation of the sum of polyphenols,
purification. The increase in the efficiency of the use of raw materials is achieved
mainly at the first stage – extraction. The yield of the sum of polyphenols was studied
depending on: the composition of the extractant, the extraction modulus, the multiplicity
of extraction, the ratio of raw materials - extractant, temperature, thickening conditions,
treatment of the aqueous residue with organic solvents, the conditions of precipitation of
the sum of polyphenols and their drying. As a result, optimal conditions for the isolation
of polyphenols from plant raw materials were selected, and the found condition
obtained the sum of polyphenols from the autumn leaves of
Crataegus pontica
K.Koch
with a yield of 4.5%. Chromatographic study of the isolated fractions revealed that the
polyphenols of the ethyl acetate fraction are mainly represented by monomeric
catechins, flavonolams and tannins. As a result, flavan-3-ols were isolated in the
individual state. The isolated flavan-3-ols have been identified as (+)-catechin, (-)-
epicatechin. The remaining compounds were separated on a Sephadex LH-20 column
using chloroform-methanol in various ratios (chloroform:methanol in a ratio of 4:1) as
an eluent, and a number of individual compounds were isolated.
Using a complex of
physicochemical methods, including: IR spectrum, UV spectrum,
13
C NMR, HPLC,
mass spectrometry, the obtained product was analyzed. In this regard, the purpose of
our work is to study the chemical composition of phenolic compounds in the leaves of
the
C. pontica
plant and to determine the structure of the isolated substances by
physicochemical methods. The structures of the isolated compounds were determined
using physicochemical methods. As a result, more than 12 polyphenols were isolated
from the leaves of
C. pontica
, such as quercetin-3-
O
-β-
D
-galactopyranoside
(hyperoside), gallic acid, quercetin-3-rutinoside, 3, 5, 7, 3', 4'- pentaoxyflavone
(quercetin),
2-(3,4-dimethoxyphenyl)-7methoxy-3,4-dihydro-2H-chromene-3,4,5,6-
tetrol, aрigenin-6-
C
-glycoside, procyanidin B, (+)-catechin (5,7,3',4'-tetraoxyflavan-3-
ol), (-)-epicatechin (5,7,3',4'-tetraoxyflavan-3-ol), ellagic acid, 1-
O
-galloyl-4-
O
-
catechin-β-
D
-glucose and caffeic acid ester with 2,3-dihydroxyglutaric acid. From
these, the last two substances were first isolated from this plant.
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