Organizing co mmittee

DESTRUCTION OF POLYPRENOLS OF VITIS VINEFERA 
DURING EXTRACTION UNDER MWI CONDITIONS 
U.T. Zokirova
, 
A. Mamadrakhimov, N.K. Khidyrova
S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of the 
Republic of Uzbekistan st. Mirzo-Ulugbek, 77, 100170 Tashkent 
E-mail: [e-mail]
 
The development of the natural sciences contributed to the emergence of new areas 
of chemistry, such as laser chemistry, photochemistry, plasma chemistry, as well as a 
new section of modern chemistry - microwave chemistry. 
Unlike conventional liquid extraction, the microwave extraction method can 
significantly reduce the extraction time due to the rapid heating of the solvent. It is 
known that microwave exposure makes it possible to minimize the temperature gradient 
and accelerate heat transfer, significantly reduce the consumption of solvents, energy 
costs, and at the same time the extractive yield of the target product is significantly 
increased. But in the process of microwave radiation, some compounds are partially 
destroyed or their structure changes. Therefore, this method does not always give 
positive results if the process is not controlled [1]. 
In this work the degree of destruction of polyprenols (PPs) of the leaves of 
Vitis 
vinefera
was studied. Previously, we studied the acylation of polyprenols and the 
extraction of leaves of 
Vitis vinefera
under microwave irradiation (MWI) and showed a 
decrease in the content of PPs [2,3]. 
In order to find out the reason for the decrease in the content of polyprenols, the 
degree of destruction of polyprenols was studied using Agilent technology LC / MC - 
6420. The results of the analysis showed that when extracted under MWI conditions for 
10 minutes, polyprenols do not undergo degradation, when extracted for 15 minutes, the 
degree of destruction will be 17.9%, within 20 minutes – 20.8% (destruction), and at 30 
minutes - 59.7% polyprenols undergo degradation. 
Thus, for the first time, the degree of destruction of polyprenols in the leaves of 
Vitis 
vinefera
under MWI conditions was studied and the optimal conditions (10 min., yield 
of PPs 70-72%) for extraction were determined.