2021, №4

сс. 70-82

Evaluation of the Polyphenolic Content and of Acetylcholinesterase Inhibition Activity of Ginkgo biloba (Ginkgo biloba L.) Leaf Extracts Obtained in Subcritical Water

2021, №4

сс. 70-82

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S.S. Khizrieva, S.N. Borisenko, E.V. Maksimenko, G.V. Zharkova, N.I. Borisenko, V.I. Minkin

Key words: subcritical water, extracts of Ginkgo biloba leaves (Ginkgo biloba L.), polyphenols, flavonoids, inhibitory AChE-activity, Alzheimer’s disease

The extracts of Ginkgo biloba (GB) leaves obtained in a medium of subcritical water
(SBW) in the temperature range of 100 °C—220 °C were studied for the first time in
order to assess the prospects for the use of GB leaf extracts for the prevention and
treatment of neurodegenerative disorders, such as, for example, Alzheimer’s disease. The
relationship of the activity of inhibition of the enzyme acetylcholinesterase (AChE)
with the content of polyphenols and flavonoids was studied. The inhibitory activity of
GB leafn extracts was expressed as IC50 values (an extract concentration that inhibits
the AChE enzyme by 50 %), determined by dose-effect curves. It is shown that the
content of polyphenols and flavonoids in the extracts obtained, and the inhibition activity
of AChE extracts depends on the extraction method: if the traditional aqueous-ethanol
extract has an anti-AChE-activity of IC50 = 3.57 mg/ml, then SBW- extracts are more
effective inhibitors of AChE. At the same time, the maximum inhibitory activity of AChE,
in a number of extracts obtained, was demonstrated by an extract obtained in the medium
of SBW at 220 °C (IC50 = 0.74 mg/ml). At the same time, the AChE-activity of the
obtained extracts of GB leaves correlates with the quantitative content of the sum of
polyphenols and flavonoids, respectively. The total content of polyphenol (the sum of
polyphenols per gallic acid or rutin) was highest in the extract obtained in medium of
SBW at 220 °C, whereas the extract obtained at 100 °C in SBW was the lowest in content
of polyphenols. The total content of flavonoids (in terms of rutin) was highest in extracts
obtained in medium of SBW at 200—220 °C (24.6 mg equivalent to rutin/g dry weight of
raw materials), and the lowest content in GB leaf extract obtained in SBW at 120 °C
(10.6 mg rutin equivalent/g dry weight).