Page 91 - Zbornik_Konf_2019

https://doi.org/10.15414/2019.9788055220703

4 International Scientific Conference Abstracts Book
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ANTIOXIDANT ACTIVITY OF EXTRACTS FROM PHYTOLACCA AMERICANA L. BERRIES

Raisa Ivanova
Institute of Genetics, Physiology and Plant Protection, Chisinau, Republic of Moldova;
E-mail.: ivanova_raisa@yahoo.com
Phytolacca americana L. (American pokeweed) is a herbaceous perennial plant that can
serve as a raw material to obtain the pharmaceutical and medicinal products as well as to
extract the natural red colorant from P. americana berries for food and textile industries.
The aim of this work was to determine the antioxidant activity of P. americana berries
extracts obtained under various conditions of antioxidant and colorant substances extraction.
The antioxidant activity was evaluated by potentiometric procedure, studying of peroxyl
radical scavenging activity of berries extracts and expressed by gallic acid equivalent (GAE).
The polyphenolic contain was appreciated by the Folin-Ciocalteu method. The concentration
of colorant substances in extracts was determined using UV-Vis spectrophotometry at 520
nm. The P. americana berries were harvested in the 2018 year in Chisinau area. The aqueous
and water-alcoholic extracts were obtained from fresh and dried berries.
The biggest amount of polyphenolic and colorant substances was found in aqueous
extracts. Using for extraction the water-alcoholic solution with a concentration of 40 and 95 %
led to a diminution of polyphenolic content by 1.5–2.0 times and reduced the concentration of
colorant substances by 3.5–4.0 times in comparison with aqueous extracts. To mention that
red colorant in all obtained extracts proportionally dissolved concomitant with extract
diluting and its concentration was easily determined by comparison the curves of optical
density dependences at 520 nm on the dilution degree of extract. These dependencies were
characterized by high approximation values (R =0.994–0.995). The color of obtained extracts
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modified from crimson bright (95 % water-alcoholic extracts) to violet (aqueous extracts)
depending on the rate of colorant substances in the dry residue of extract, which varied from
0.94 to 5.12 %.
Evaluated antioxidant activities of P. americana berries extracts were in direct
proportional dependences on the polyphenolic contents (r =0.956). Among the tested
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extracts, the aqueous extracts demonstrated stronger antioxidant activity equal with
17.52±0.04 and 28.87±0.88 µM GAE/g of dry residue, respectively extracts obtained from
dried and fresh berries. The water-alcoholic extracts exhibited the antioxidant activity that
ranged from 7.53±0.09 µM GAE/g (extracts with 95 % alcohol from dried berries,) to
19.27±0.52 µM GAE/g (extracts with 40 % alcohol from fresh berries).
To conclude, the P. americana aqueous extracts from fresh and dried berries was richer
in biochemical constituents and possessed the highest antioxidant activity. On the other hand,
these extracts are unstable to degradation and this fact must be taken into account when
operating with them.

Keywords: Phytolacca americana, berry, extract, polyphenolic, colorant, antioxidant activity.
Acknowledgments
The author is grateful to the International Visegrad Scholarship Fund for supporting this research by
grant (51910230).

4 International Scientific Conference Agrobiodiversity Nutrition, Health and Quality of Human and Bees Life |91
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September 11–13, 2019