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Biologically active and reserve substances of
Siberian peonies
Vera A. Kostikova
1
*
, Olga V. Kalendar
1
, Nikolai A. Tashev
2
,
Andrey S. Erst
1
, and Olga Yu.
Vasilyeva
1
1
Central Siberian Botanical Garden, Siberian Branch of Russian Academy of Sciences (CSBG SB
RAS), Zolotodolinskaya Str., 101, Novosibirsk 630090, Russia
2
University of Forestry,
Faculty of Business Management (FBM), Sofia 1756, Bulgaria
Abstract. Levels of biologically active and reserve substances were
investigated in the leaves and rhizomes of Paeonia anomala L., P. hybrida
Pall., and P. lactiflora Pall. The peonies’ leaves are rich in ascorbic acid
(1205.7 mg/100g in P. anomala) and tannins (15.9% in P. lactiflora and
15.7% in P. anomala) at the beginning of the growth season.
Concentrations of flavonols, pectins, and carotenoids in the Siberian
peonies are low at the beginning of the growth season. P. lactiflora is a
promising species for further research on the set and levels of biologically
active and reserve substances in rhizomes because this species stands out
among the three Siberian species in terms of the levels of catechins (1297.8
mg/100g), protopectins (10.1%), saponins (19.2%), and sugars (22.1%) in
rhizomes. In these parts of the plant, starch (18.6%) accumulates the most
in P. hybrida among the studied peonies species. Concentrations of the
analyzed substances in the rhizomes of the peonies change significantly by
the end of the growth season and vary widely among these species. Levels
of ascorbic acid (except for P. hybrida), protopectins, and starch increase
significantly while concentrations of catechins and sugars decrease in the
rhizomes by the end of the growth season.
1 Introduction
The genus Paeonia L. includes 33 species, distributed mainly in Europe, the Mediterranean,
and East and Southeast Asia [1]. There are three species in the flora of Siberia: P. anomala
L., P. hybrida Pall., and P. lactiflora Pall. [2].
The Siberian species belong to two sections: Flavonia Kem.-Nath. (P. lactiflora) and
Sternia Kem.-Nath. (P. anomala and P. hybrida). P. lactiflora has one to seven milky-white
flowers per shoot, while P. anomala and P. hybrida have one purple-pink flower per shoot
[1]. The leaves of P. lactiflora are double trifoliate, in contrast to the triple trifoliate pinnate
leaves of P. anomala and P. hybrida [3]. Paeonia hybrida reproduces via numerous
spindle-shaped tuberous parts of lateral roots, unlike the other two species, which usually
reproduce as part of the rhizome with a bud at the base of the shoot [4].
* Corresponding author: serebryakova-va@yandex.ru
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons
Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
BIO Web of Conferences 38, 00061 (2021)
Northern Asia Plant Diversity 2021
https://doi.org/10.1051/bioconf/20213800061
According to studies, early flowering P. lactiflora, P. anomala, and P. hybrida are of
great interest in the harsh climate of Siberia. In addition, the forest species P. lactiflora and
P. anomala have the longest growth season and accordingly are characterized by the
preservation of decorative features.
Wild species of peonies and the varieties created from them are ornamental plants and
have medicinal properties
.
Peonies contain a wide range of biologically active substances
belonging to various classes of chemical compounds: carbohydrates, terpenoids, steroids,
phenol carboxylic acids, phenolic glycosides, flavonoids, tannins, vitamins, iridoids, and
trace elements [5–7]. Only P. anomala L. is used for medicinal purposes in conventional
medicine [8]. Nonetheless, the amount of this species collected in the wild as raw materials
for industrial purposes is currently limited due to the small size of its wild populations.
Therefore, it is important to investigate the chemical composition and medicinal effects of
other species that either grow in this region or have a high potential for introduction into an
environment with these climatic conditions.
The aim of this study was to quantify biologically active and reserve substances in the
leaves and rhizomes of the P. lactiflora, P. anomala, and P. hybrida introduced into the
forest-steppe environment of the Novosibirsk Region (Oblast).
2 Materials and methods
The leaves and rhizomes of P. lactiflora, P. anomala, and P. hybrida were collected at the
beginning of the growth season (in May 2017) and at its end (17 August 2017) from
“Collections of living plants indoors and outdoors” (unique scientific unit No. 440534 of
CSBG SB RAS) in a garden plot located at a forest-steppe site with gray forest soil and a
mean yearly temperature/precipitation of 1.8 °C/448 mm. The raw materials were dried and
crushed to obtain a representative sample for the analysis.
The quantitation of flavonols was carried out by the spectrophotometric aluminum
chloride method. Concentrations of flavonols were calculated as rutin equivalents (Sigma-
Aldrich) [9]. The level of catechins was measured by a technique based on the ability of
catechins to give crimson staining when mixed with a solution of vanillin in concentrated
hydrochloric acid. The conversion factor was calculated using catechin from a commercial
source (Sigma-Aldrich) [10]. The quantitation of tannins (hydrolyzable tannins) was
performed via the approach proposed by L.M. Fedoseeva [11], where tannin from Sigma-
Aldrich served as a standard sample. The quantification of ascorbic acid was carried out by
titration. This technique is based on the reducing properties of ascorbic acid [12]. Pectin
substances (pectins and protopectins) were quantitated by a carbazole-free method based on
specific yellow-orange staining of uronic acids in the presence of thymol in a sulfuric-acid
solution. The concentrations of pectin substances were calculated as galacturonic-acid
equivalents [13]. Levels of saponins were determined by the gravimetric method [14].
Levels of carotenoids was determined in an acetone–ethanol extract [12, 15]. Sugars were
quantified by the method of A.S. Shvetsov and E.H. Lukyanenko, which is based on
potassium ferricyanide reduction by reducing sugars to ferricyanide in an alkaline solution.
The sugars were quantitated using a calibration curve plotted by means of glucose standards
[12]. To quantify starch, the raw material was hydrolyzed with a hydrochloric acid solution
(10 g/l) for 6 h. Because glucose constitutes a 0.89996 proportion of starch by weight, the
resulting difference (in %) was multiplied by this quotient, and starch content of the
analyzed samples was determined in this way [16]. All the experiments were set up with
two biological replicates and three technical replicates per treatment. All biochemical
parameters were calculated for the mass of absolutely dry raw materials.
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3 Results and discussion
First, the concentrations of phenolic compounds—flavonols, catechins, and tannins—and
those of ascorbic acid, pectin substances, saponins, and carotenoids were determined in the
leaves and rhizomes of the three Paeonia species at the beginning of the growth season
(Table 1). It was revealed that flavonol levels in the leaves are almost identical between the
peonies of the section Sternia (P. anomala and P. hybrida); these concentrations are
slightly higher than those in the leaves of P. lactiflora. It should be noted that the levels of
flavonols in the peonies’ leaves were rather low at the beginning of the growth season.
Flavonols were not detectable in the rhizomes of the studied peonies. The concentration of
tannins was found to be higher in the leaves of P. lactiflora and P. anomala than in their
rhizomes (two- to threefold). On the contrary, levels of catechins are higher in the
underground organs of P. lactiflora and P. anomala than in their leaves, whereas in
P. hybrida, these levels are higher in the leaves. P. lactiflora stands out among the three
analyzed species in terms of the catechin content of the rhizomes (1297.8 mg/100g). The
concentration of ascorbic acid turned out to be six- or elevenfold higher in the leaves of the
peonies than in their rhizomes. The highest level of ascorbic acid was registered in the
leaves of P. anomala (1205.7 mg/100g). The concentration of pectins in the leaves and
rhizomes of the peonies is rather low, and similarly to catechins, the concentration of
pectins in P. lactiflora and P. anomala is higher in the rhizomes than leaves, whereas in P.
hybrida, it is higher in the leaves. The level of protopectins was found to significantly
exceed that of pectins. In rhizomes, the concentration of protopectins is the highest in P.
lactiflora (10.1%), while in the two species of the Sternia section, this concentration is
within 6–7%. The concentration of protopectins proved to be higher in the underground
organs of the peonies than in their leaves. The level of saponins is almost identical between
the rhizomes and leaves of the three peonies. Their highest concentration was found in the
leaves and rhizomes of P. lactiflora (19%). Carotenoids, just as flavonols, are present only
in the peonies’ leaves. Their concentration is the highest in the leaves of the section Sternia
species (P. anomala and P. hybrida): 77.7 mg/100g and 56.9 mg/100g, respectively, which
is still rather low.
Next, reserve substances (starch and sugars) in the leaves and rhizomes of the Siberian
peonies were quantified at the beginning of the growth season (Table 1). It was revealed
that the peonies of the Sternia section contain more starch in the rhizomes as compared to P.
lactiflora. P. hybrida is remarkable in this regard: the rhizome starch level reaches 18.6%.
The sugar concentration is the highest in P. lactiflora rhizomes and P. hybrida leaves. It
must be mentioned that in P. lactiflora, this concentration is higher in the rhizomes than in
the leaves, whereas in the other two species, the opposite is true.
In addition, the levels of biologically active and reserve substances in the rhizomes of
the Siberian peonies were determined at the end of the growth season. The levels of
protopectins in the rhizomes of all three peonies (11.3% in P. lactiflora, 15.9% in P.
anomala, and 8.16% in P. hybrida) are higher at the end of the growth season than at its
beginning (Fig. 1). On the contrary, the concentration of catechins (245.3 mg/100g in P.
lactiflora, 60.3 mg/100g in P. anomala, and 45.8 mg/100g in P. hybrida) decreases toward
the end of the growth season (Fig. 2). The level of ascorbic acid in the rhizomes of P.
lactiflora (113.6 mg/100g) and P. anomala (158.7 mg/100g) is higher at the end of the
growth season, whereas in P. hybrida (85.9 mg/100g), it is higher at the beginning (Fig. 2).
The concentration of pectins in the rhizomes of P. anomala (0.9%) and P. hybrida (1.0%) is
higher at the end of the growth season, whereas in P. lactiflora (0.4 mg/100g), it is higher at
the beginning. Levels of saponins in rhizomes barely changed in P. lactiflora (18.9%) and
P. anomala (12.2%) during the growth season but doubled in P. hybrida (12.3%; Fig. 1).
The sugar level in rhizomes significantly decreased (to 7.6% in P. lactiflora, to 4.8% in P.
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BIO Web of Conferences 38, 00061 (2021)
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anomala, and to 5.0% in P. hybrida), while the starch level doubled (to 21.8% in P.
lactiflora, to 31.2% in P. anomala, and to 28.6% in P. hybrida) as compared to the
beginning of the growth season (Fig. 1).
Table 1. Concentrations of biologically active and reserve substances in Siberian peonies at the
beginning of the growth season
P. lactiflora
22.05.
20
17
P. anomala
22.05.
20
17
P. hybrida
25.05.
20
17
Substances leaves rhizomes
leaves rhizomes
leaves rhizomes
Moisture, %
85.70 78.60 82.06 77.61 79.56 84.39
Flavonols, %
1.47 no 1.95 no 1.96 no
Catechins,
mg/100g 103.50 1297.80 76.40 81.30 96.40 76.90
Tannins, %
15.87 5.47 15.72 6.48 12.57 6.13
Ascorbic acid,
mg/100g 845.45 90.65 1205.61 87.54 868.40 203.08
Pectins, %
0.41 0.74 0.68 0.74 0.63 0.53
Protopectins, %
4.13 10.10 5.96 6.91 4.45 5.68
Saponins, %
19.21 18.94 12.06 12.69 6.47 7.23
Carotenoids,
mg/100g 19.70 no 77.70 no 56.90 no
Sugar
, % 18.95 22.06 17.61 13.62 20.65 12.36
Starch
, % – 12.19 – 15.80 – 18.64
Note: no, not found; “–“, not tested.
Fig. 1. Levels of protopectins, saponins, sugars, and starch in the rhizomes of the Siberian peonies at
the beginning (1) and at the end (2) of the growth season.
Fig. 2. Levels of ascorbic acid and catechins in the rhizomes of the three peonies at the beginning (1)
and at the end (2) of the growth season.
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4 Conclusion
The leaves and rhizomes of the Siberian species of peonies grown on the territory of the
CSBG SB RAS (Novosibirsk) contain biologically active and reserve substances in
sufficient amounts for their further study as additional sources of medicinal raw materials
for the pharmaceutical industry and for rational use of Siberian phytoresources.
The work was supported by a publicly funded project of the CSBG SB RAS, No.
АААА-А21-121011290025-2.
Acknowledgements. The English language was corrected and certified by shevchuk-
editing.com
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