Profile of Bioactive Compounds in the Morphological Parts of Wild Fallopia japonica (Houtt) and Fallopia sachalinensis (F. Schmidt) and Their Antioxidative Activity

The aim of this study was to determine the content of triterpenoids and polyphenols, and antioxidative activity in leaves, stalks, and roots of plants from the species Fallopia as well as to present the main relationship between them. Polyphenolic compounds and triterpenoids were identified with liquid chromatography-photodiode detector-mass spectrometry/quadrupole time of flight (LC-MS-Q/TOF; qualitatively) and quantified with an ultra-performance liquid chromatography-photodiode detector (UPLC-PDA (quantitatively), and their antioxidative activity was determined with radical scavenging capacity (ABTS) and oxygen radical absorbance capacity (ORAC) assays. Generally, the wild Fallopia japonica Houtt. species had 1.2 times higher content of bioactive compounds and antioxidative activity than Fallopia sachalinensis. Contents of polyphenolic compounds determined in leaves, stalks, and roots were on average 17.81, 10.60, and 9.02 g/100 g of dry weight (DW), whereas the average contents of triterpenoids reached 0.78, 0.70, and 0.50 g/100 g DW, respectively. The leaves were a better source of polymeric procyanidins, phenolic acids, flavones, and flavonols, as well as oleanolic and ursolic acids than the other morphological parts of the tested plants. However, the roots were an excellent source of flavan-3-ols (monomeric and oligomer) and stilbenes, such as resveratrol, and their derivatives. The results obtained showed significant differences between plants of the wild Fallopia species and their morphological parts, and enabled selecting the most valuable morphological part of the tested plants to be used for food enrichment and nutraceuticals production. Therefore, the leaves seem to be the best as potential food additives for health, due to the above-average content of polyphenolic compounds and triterpenoids. In turn, roots, with their high contents of stilbenes and polyphenolic compounds, represent a good material for the medical, pharmaceutical, and cosmetic industries. The principal component analysis of the plants of wild Fallopia species and their morphological parts confirmed significant differences in their chemical composition.


Introduction
A growing interest has recently been observed in natural medicine, with phytotherapy being its main branch. According to the World Health Organization (WHO), currently, nearly 80% of the world's population relies on this form of medicine as part of health care. Herbal medicine is also more
The major group identified in plants of the wild Fallopia species and their morphological parts was flavan-3-ols (monomeric, oligomeric and polymeric procyanidins), which on average accounted for 88% of total phenolic compounds. The content of polymeric procyanidins was confirmed using the phloroglucinol method (UPLC-FL). This method proves better in providing more information on the polymeric procyanidins in the plants, because UPLC-PDA-based analyses allow partial detection of the proanthocyanidin fraction. In addition, the profile of flavan-3-ols (monomers and oligomers) was similar to that reported by the other authors [15]. Polymeric procyanidins predominated in leaves and stalks and accounted for 72% and 85%, whereas monomers and oligomers accounted for only 7%. However, higher contents of monomers and oligomers-around 32%-and of polymeric procyanidins-around 60%-were observed in roots. The average content of flavan-3-ols in F. japonica (Houtt.) was 11.64 g/100 g DW and was 1.2 times statistically (p < 0.05) higher than in F. sachalinensis (F. Schmidt) ( Table 2). Around 2.3 and 3.8 times higher content of monomers and oligomers was noted in roots than in leaves and stalks. Additionally, around 1.4 and 1.7 times higher content of polymeric procyanidins was determined in leaves than in stalks and roots. The flavan-3-ols, mainly polymeric procyanidins, are very important plant constituents because they affect the flavor of the finished products and exhibit biological activities [26].
The next group identified in plants of wild Fallopia species and their morphological parts was flavones and flavonols, represented by fifteen identified compounds. Of these, five flavonols were identified for the first time in the species Fallopia compared to the studies of other authors [10][11][12][13][14][15]. Three types of flavone and flavonol derivatives with an MS/MS fragment at m/z 301, 285, typical of quercetin, luteolin, and kaempferol derivatives, were found in Fallopia plants and their parts. Luteolin derivatives were identified only in leaves of Fallopia. Luteolin was identified as -3-O-rhamnoside (m/z 447 due to the loss of 162 Da and m/z 431 due to the loss of 146 Da) [12,13] ( Table 1). Two quercetin derivatives exhibiting a fragment ion at m/z 301 characteristic for this compound (quercetin) were identified as -3-O-rhamno-glucoside (m/z 609), but only in leaves and stalks of Fallopia. Two kaempferol derivatives compared with UV-VIS absorption and the fragment ion at m/z 285 characteristic for kaempferol were identified as -3-O-galactoside, and -3-O-glucoside (m/z 447 due to the loss of 162 Da and m/z 431 due to the loss of 146 Da) [15] (Table 1). These compounds were mainly located in leaves and accounted for 12% of total phenolics, but in stalks they represented 5% and in roots 0.2% of total phenolic compounds. A higher content of flavones and flavonols was determined in F. japonica (Houtt.); it was on average 0.99 g/100 g DW and was around 1.5 times significantly (p < 0.05) higher than in F. sachalinensis (F. Schmidt) ( Table 2). The average content of flavones and flavonols of Fallopia species was similar to Tanacetum vulgare and higher than in other medicinal plants grown in Poland such as Salvia officinalis (around 4.0 times), Rosmarinus officinalis (around 1.4 times), and Archangelica officinalis (around 1.2 times) [24]. The content of flavones and flavonols in plants of Fallopia species was also higher than in Algerian medicinal plants such as Anthemis arvensis (around 1.1 times), Artemisia campestris (around 1.3 times), and Globularia alypum (around 2.1 times) [24]. The highest content of flavones and flavonols was identified in leaves and it was around 3.6 and 16.0 times higher than in stalks and roots, respectively. Similar results were obtained by analyzing their contents in the morphological parts of Allium ursinum [17]. Their content in leaves, stalks, and roots of F. japonica (Houtt.) was around 1.6, 1.2, and 17.7 times higher than in the same morphological parts of F. sachalinensis (F. Schmidt), respectively. In the analyzed plants, quercetins were the major subclass of flavones and flavonols and represented 97% of their total content, including quercetin 3-O-rhamnoside, and quercetin 3-O-pentoside that accounted for 73% and 11%, respectively. Quercetin derivatives are important for bodily health, because they have a strong antioxidative activity [16].
The second group identified in plants of Fallopia species and their morphological parts were phenolic acids which in their leaves, stalks, and roots accounted for 9%, 2%, and 0.5% of total polyphenolic compounds, respectively. In addition, the profile of phenolic acids was similar to that reported by the other authors [15]. A higher content of phenolic acids was found in F. japonica (Houtt.); it reached around 0.66 g/100 g DW and was 1.1 times significantly (p < 0.05) higher than in F. sachalinensis (F. Schmidt) ( Table 2). The average content of flavones and flavonols of Fallopia species was higher than in other medicinal plants grown in Poland such as Salvia officinalis (around 1.7 times), Rosmarinus officinalis (around 1.4 times), and Archangelica officinalis (around 1.2 times) [19]. The highest content of phenolic acids was determined in leaves and was around 7.0 and 41.0 times higher than in stalks and roots of the analyzed plants. Similar results were obtained by analyzing the content of these compounds in the morphological parts of Allium ursinum [17]. In plants of the analyzed Fallopia species, the cis-3-O-caffeoylquinic and caftaric acids were major compounds in leaves, and accounted for 29% and 26% of total phenolic compounds, whereas cis-3-O-caffeoylquinic and 5-O-caffeoylquinic acids were predominant compounds in the stalk (accounting for 32% and 28%), while caftaric and 4,5-Di-O-caffeoylquinic acids were the major compounds found in roots (accounting for 21% and 42%). These results corroborated findings reported by Park et al. [27], who stated that an important aspect of the plants was the presence of caffeoylquinic acid, which was the prevailing compound known to affect their flavor. The last group identified in plants of Fallopia species and their morphological parts was represented by stilbenes, which, in their leaves, stalks, and roots, accounted for 0.5%, 1%, and 7% of total polyphenolic compounds, respectively. Among the eight compounds identified, one stilbene was identified for the first time in the species Fallopia compared to the studies of other authors [10][11][12][13][14][15]. The compound with Rt = 5.90 and λ = 303 nm having a molecular ion at m/z 389 and an MS/MS fragment ion at m/z 227 [M-162-H] − was identified as resveratroloside (Table 1). These compounds were identified based on their standards and available data [10,12,14], and were found only in roots. The reported research indicates that F. japonica (Houtt.) and F. sachalinensis (F. Schmidt), especially their roots, are an excellent source of stilbenes, mainly resveratrol, which are rarely found in other plants. A higher content of stilbenes was found in F. japonica (Houtt.) and was around 1.7 times significantly (p < 0.05) higher than in F. sachalinensis (F. Schmidt). The average content of piceid and resveratrol in plants of Fallopia species was around 1.8 and 1.4 times higher than in Japanese knotweed (the medicinal plant) [12]. Additionally, the content of piceid in grape cv. Casteao from Portugal was around 15 times lower than that in plants of Fallopia species and six times lower than in leaves of this plant [28]. The highest content of stilbenes was determined in roots of Fallopia species plants and was around 7.4 and 11.1 times higher than in their leaves and stalks. In the analyzed Fallopia species, the trans-piceid compounds were major compounds and accounted for 55% of total phenolic compounds. The content of resveratrol and its derivatives, besides flavan-3-ols in roots, can be used as an important indicator of the medicinal potential of plants with respect to their bioactive compounds, nutraceutical value, and also potential use. Additionally, resveratrol is the most important compound of the stilbenes, which are representatives of polyphenolic phytoalexins. They are produced by plants as protective substances against abiotic or biotic stress. Resveratrol and its derivatives offer some health benefits, such as anticarcinogenic, antioxidative, antimicrobial, anti-inflammatory, and antiaging properties [29].

Determination of Tritepenoids
The outcomes of triterpenoids determination in plants of F. japonica (Houtt.) and F. sachalinensis (F. Schmidt) and their morphological parts are shown in Figure 1. The analyzed plants of Fallopia species, especially their leaves and rhizomes, had a similar profile of triterpenoids to that reported in earlier works [15], whereas contents of these compounds differed between wild and cultivation species [15]. Besides polyphenols, triterpenoids are an important group of bioactive compounds exhibiting biological activities including anticarcinogenic, anti-inflammatory, antifungal and antioxidative ones [16,30,31]. These compounds were identified in stalks and roots of the test plants for the first time ever. The average content of triterpenoids was 0.72 g/100 g DW in F. japonica (Houtt.) and was around 1.3 times significantly (p < 0.05) higher than in F. sachalinensis (F. Schmidt). The highest content of triterpenoids was found in leaves and reached 0.78 g/100 g DW, which was around 1.1 and 1.5 times higher than in stalks and roots, respectively. According to Lachowicz et al. [17], the content of triterpenoids in leaves, stalks, and roots of Allium ursinum was around 4, 3, and 1.4 times higher than in the morphological parts of plants of wild Fallopia species. In turn, Lachowicz et al. [17] showed a similar content of triterpenoids in the analyzed leaves and their 1.3 times lower content in rhizomes compared to the values determined in leaves in our results. The differences in the content of triterpenoids in the analyzed morphological parts are due to the fact that these compounds are mainly accumulated in the waxy layer of the plants [21,30]. Moreover, their content in plants depends on many factors, including cultivar, degree of maturity, morphological parts, climate, and environmental conditions [31]. The major compound in the analyzed Fallopia species was found to be ursolic acid (constituting from 54% to 58% of total triterpenoids), followed by oleanolic acid (from 14% to 29%) and betulinic acid (from 13% to 33%). The ursolic and oleanolic acids prevailed in the leaves; in leaves of F. japonica their contents were around 1.4 times significantly (p < 0.05) higher than in these of F. sachalinensis. Betulinic acid predominated in the stalks. Similar results were obtained by Lachowicz et al. [17] (in A. ursinum), Szakiel et al. [30] (in Prunus avium, Malus domestica), and Loza-Mejía and Salazar [16] (in Olea europaea leaves).

Antioxidant Activity
The antioxidative activity of foodstuffs is influenced by various mechanisms, and can be determined using different tests pertaining to various mechanisms. Therefore, in vitro assays: radical scavenging capacity (ABTS) and oxygen radical absorbance capacity (ORAC), were used to evaluate the antioxidative activity of F. japonica (Houtt.) and F. sachalinensis (F.Schmidt) plants and their morphological parts-leaves, stalks, and roots ( Figure 2). A significant variation (p < 0.05) was found in the antioxidative activity of the analyzed materials. Its average values in F. japonica (Houtt.) were 58.91 (ABTS assay) and 24.11 (ORAC assay) mmol Trolox/100 g DW and were around 1.1 times higher than in F. sachalinensis (F.Schmidt). The highest antioxidative activity was analyzed in the leaves of F. japonica and in the roots of F. sachalinensis, i.e., 81.12 and 71.22 (ABTS assay) and 30.42 and 30.85 (ORAC assay) mmol Trolox/100 g DW, respectively. In contrast, the lowest antioxidative activity was measured in the stalks of both Fallopia species and reached 31.79 and 14.11 mmol Trolox/100 g DW (ABTS and ORAC assay, respectively) on average. These differences in the antioxidative activity of plants of the analyzed Fallopia species and their morphological parts could be attributed to various contents of polyphenolic compounds (Tables 2-5) and triterpenoids (Figure 1). It is generally acknowledged that bioactive compounds, including polyphenolic compounds and triterpenoids, may affect medicinal plants' antioxidant activity. A strong and positive correlation was found in the analyzed material between the antioxidative activity and contents of total phenolic compounds, phenolic acids, polymeric procyanidins, as well as oleanolic and ursolic acids (p < 0.05). In turn, negative correlations were found between contents of betulinic acid and antioxidants (p < 0.05). Furthermore, Fallopia species presented levels of antioxidants comparable with those of other plants, such as Rosmarinus officinalis [19], having high contents of bioactive compounds with proven health benefits. The Fallopia species plants presented a higher antioxidative activity than other medicinal plants such as Melissae folium (around 2.0 times), Spiraea herba (around 3.4 times), Uvea ursi folium (around 3.9 times), Rubi fructose folium (around 4.3 times) [21], Salvia officinalis (around 3.0 times), and Archangelica officinalis (around 3.7 times) [19]. Moreover, their leaves and roots exhibited a higher antioxidative activity than other medicinal plants such as Melissae folium (around 1.2 times), Spiraea

Antioxidant Activity
The antioxidative activity of foodstuffs is influenced by various mechanisms, and can be determined using different tests pertaining to various mechanisms. Therefore, in vitro assays: radical scavenging capacity (ABTS) and oxygen radical absorbance capacity (ORAC), were used to evaluate the antioxidative activity of F. japonica (Houtt.) and F. sachalinensis (F. Schmidt) plants and their morphological parts-leaves, stalks, and roots ( Figure 2). A significant variation (p < 0.05) was found in the antioxidative activity of the analyzed materials. Its average values in F. japonica (Houtt.) were 58.91 (ABTS assay) and 24.11 (ORAC assay) mmol Trolox/100 g DW and were around 1.1 times higher than in F. sachalinensis (F. Schmidt). The highest antioxidative activity was analyzed in the leaves of F. japonica and in the roots of F. sachalinensis, i.e., 81.12 and 71.22 (ABTS assay) and 30.42 and 30.85 (ORAC assay) mmol Trolox/100 g DW, respectively. In contrast, the lowest antioxidative activity was measured in the stalks of both Fallopia species and reached 31.79 and 14.11 mmol Trolox/100 g DW (ABTS and ORAC assay, respectively) on average. These differences in the antioxidative activity of plants of the analyzed Fallopia species and their morphological parts could be attributed to various contents of polyphenolic compounds (Table 2) and triterpenoids (Figure 1). It is generally acknowledged that bioactive compounds, including polyphenolic compounds and triterpenoids, may affect medicinal plants' antioxidant activity. A strong and positive correlation was found in the analyzed material between the antioxidative activity and contents of total phenolic compounds, phenolic acids, polymeric procyanidins, as well as oleanolic and ursolic acids (p < 0.05). In turn, negative correlations were found between contents of betulinic acid and antioxidants (p < 0.05). Furthermore, Fallopia species presented levels of antioxidants comparable with those of other plants, such as Rosmarinus officinalis [19], having high contents of bioactive compounds with proven health benefits. The Fallopia species plants presented a higher antioxidative activity than other medicinal plants such as Melissae folium (around 2.0 times), Spiraea herba (around 3.4 times), Uvea ursi folium (around 3.9 times), Rubi fructose folium (around 4.3 times) [21], Salvia officinalis (around 3.0 times), and Archangelica officinalis (around 3.7 times) [19]. Moreover, their leaves and roots exhibited a higher antioxidative activity than other medicinal plants such as Melissae folium (around 1.2 times), Spiraea herba (around 2.1 times), Uvea ursi folium (around 2.4 times), and Rubi fructose folium (around 2.6 times) [20]. herba (around 2.1 times), Uvea ursi folium (around 2.4 times), and Rubi fructose folium (around 2.6 times) [20].

Principal Component Analysis (PCA)
The PCA showed differences between Fallopia species and between leaves, stalks, and roots in their triterpenoids content, polyphenols profiles, and antioxidant activity. Two primary PCs for the study of Fallopia species and their parts amounted to 93.80%: i.e., 64.94% for PC1, and 28.88% for PC2 ( Figure 3). PC1 illustrated the differences between the content of triterpenoids, polyphenols, and antioxidant activity (ABTS, ORAC), whereas PC2 illustrated the comparison of procyanidins, stilbenes with betulinic acid. The PCA indicated also some differences between the leaves, stalks, and roots of F. japonica and F. sachalinensis. For example, leaves of both wild Fallopia species had the highest antioxidative activity (ABTS and ORAC). Also, leaves had a higher content of oleanolic acid, flavonols, quercetin, lutein derivatives, flavan-3-ols (monomers and oligomers), phenolic acids, feruloylquini, caffeoylquinic, coumaroylquinic, and caftaric acids. Stalks of wild Fallopia japonica were characterized by a high amount of kaempferol derivatives, triterpenoids, ursolic acid, and polymeric procyanidins. Stalks of wild Fallopia sachalinensis were characterized by a high content of galloyl glucose and betulinic acid. The roots of both wild Fallopia species were a good source of stilbenes, piceid and resveratrol derivatives as well as of a procyanidin dimer B, (−)-epicatechin, and a procyanidin tetramer B, (+)-catechin.
Principal component analysis (PCA) has been used earlier to depict correlations between the analytical compounds and cultivars tested. Lachowicz et al. [15] employed PCA to evaluate a correlation between the phenolic, tetraterpenoid, and triterpenoid fractions and the analyzed plants from cultivation Fallopia species and their morphological parts. Lachowicz et al. [18] presented the PCA to distinguish bulbs, leaves, flowers, and stems of A. ursinum L., based on the phytochemical composition and antioxidative properties. Finally, Sproull et al. [31] used PCA to determine longterm changes in the composition of four herbaceous plants.

Principal Component Analysis (PCA)
The PCA showed differences between Fallopia species and between leaves, stalks, and roots in their triterpenoids content, polyphenols profiles, and antioxidant activity. Two primary PCs for the study of Fallopia species and their parts amounted to 93.80%: i.e., 64.94% for PC1, and 28.88% for PC2 ( Figure 3). PC1 illustrated the differences between the content of triterpenoids, polyphenols, and antioxidant activity (ABTS, ORAC), whereas PC2 illustrated the comparison of procyanidins, stilbenes with betulinic acid. The PCA indicated also some differences between the leaves, stalks, and roots of F. japonica and F. sachalinensis. For example, leaves of both wild Fallopia species had the highest antioxidative activity (ABTS and ORAC). Also, leaves had a higher content of oleanolic acid, flavonols, quercetin, lutein derivatives, flavan-3-ols (monomers and oligomers), phenolic acids, feruloylquini, caffeoylquinic, coumaroylquinic, and caftaric acids. Stalks of wild Fallopia japonica were characterized by a high amount of kaempferol derivatives, triterpenoids, ursolic acid, and polymeric procyanidins. Stalks of wild Fallopia sachalinensis were characterized by a high content of galloyl glucose and betulinic acid. The roots of both wild Fallopia species were a good source of stilbenes, piceid and resveratrol derivatives as well as of a procyanidin dimer B, (−)-epicatechin, and a procyanidin tetramer B, (+)-catechin.
Principal component analysis (PCA) has been used earlier to depict correlations between the analytical compounds and cultivars tested. Lachowicz et al. [15] employed PCA to evaluate a correlation between the phenolic, tetraterpenoid, and triterpenoid fractions and the analyzed plants from cultivation Fallopia species and their morphological parts. Lachowicz et al. [18] presented the PCA to distinguish bulbs, leaves, flowers, and stems of A. ursinum L., based on the phytochemical composition and antioxidative properties. Finally, Sproull et al. [31] used PCA to determine long-term changes in the composition of four herbaceous plants.

Plant Materials
Leaves, stalks, and roots of wild Fallopia japonica (Houtt) and Fallopia sachalinensis (F.Schmidt) species were used in the study. The material was divided into morphological parts to check the distribution of the phytochemicals tested. Samples of the growing wild material (~1.0 kg each) were collected at the beginning of September 2018 near the Odra River in Wrocław, Poland (N°51.125988 E°7/08111) (riverside area, highly hydrated).

Determination of Polyphenols
All analyses of polyphenols in the tested samples were carried out using an ACQUITY Ultra Performance LC system (UPLC) equipped with a binary solvent manager (Waters Corp., Milford,

Plant Materials
Leaves, stalks, and roots of wild Fallopia japonica (Houtt) and Fallopia sachalinensis (F. Schmidt) species were used in the study. The material was divided into morphological parts to check the distribution of the phytochemicals tested. Samples of the growing wild material (~1.0 kg each) were collected at the beginning of September 2018 near the Odra River in Wrocław, Poland (N • 51.125988 E • 7/08111) (riverside area, highly hydrated).

Determination of Polyphenols
All analyses of polyphenols in the tested samples were carried out using an ACQUITY Ultra Performance LC system (UPLC) equipped with a binary solvent manager (Waters Corp., Milford, MA, USA), a UPLC BEH C18 column (1.7 µm, 2.1 mm × 50 mm, Waters Corp., Milford, MA, USA), and a Q-Tof Micro mass spectrometer (Waters, Manchester, UK) with an ESI source operating in negative and positive modes. The analysis was carried out using full-scan, data-dependent MS scanning from m/z 100 to 1500. Leucine enkephalin was used as the reference compound at a concentration of 500 pg/µL, and a flow rate of 2 µL/min, and the [M − H] − ion at 554.2615 Da was detected. The [M − H] − ion was detected during 15-min analysis performed within ESI−MS accurate mass experiments, which were permanently introduced via the LockSpray channel using a Hamilton pump. The lock mass correction was ±1.000 for the mass window. The mass spectrometer was operated in the negative-ion mode, set to the base peak intensity (BPI) chromatograms, and scaled to 12,400 counts per second (cps) (100%). The optimized MS conditions were as follows: capillary voltage of 2500 V, cone voltage of 30 V, source temperature of 100 • C, dissolution temperature of 300 • C, and dissolution gas (nitrogen) flow rate of 300 L/h. Collision-induced fragmentation experiments were performed using argon as the collision gas, with voltage ramping cycles from 0.3 to 2 V. The data obtained from UPLC−MS were subsequently entered into the MassLynx 4.0 ChromaLynx Application Manager software.
A protocol described earlier by Lachowicz et al. [15] was followed during the extraction and determination of phenolic compounds. The mobile phase consisted of solvent A (4.5% formic acid, v/v) and solvent B (100% acetonitrile). The runs were monitored at the following wavelengths: phenolic acids at 320 nm, flavonols at 340 nm, anthocyanins at 520 nm, flavan-3-ols at 280 nm. The PDA spectra were measured over the wavelength range of 200-600 nm in steps of 2 nm. The results were expressed as g/100 g DW.

Determination of Proanthocyanidins
Phloroglucinolysis of samples was performed according to the protocol described by Lachowicz et al. [15]. Phloroglucinolysis products were separated on a Cadenza CD C18 (75 mm × 4.6 mm, 3 µm) column (Imtakt, Japan). Analysis was carried out using a Waters (Milford, MA) system equipped with Waters 474 diode array and scanning fluorescence detectors and Waters 717 plus autosampler. The mobile solvents were 0.25% aqueous acetic acid (A) and acetonitrile (B). Fluorescence detection was monitored at 278 nm and 360 nm. The calibration curves were plotted using (+)-catechin and (−)-epicatechin-phloroglucinol adduct standards. All data were obtained in triplicate. The results were expressed as g/100 g DW

Determination of Triterpenoids
Sample extraction was performed as described by Farneti et al. [32]. Ursolic, oleanolic, and betulinic acids were identified and quantified using the ACQUITY Ultra Performance LC system with a binary solvent manager (Waters Corp., Milford, MA, USA), a UPLC BEH C18 column (1.7 µm, 2.1 mm × 150 mm, Waters Corp., Milford, MA, USA), and a Q-TOF mass spectrometer (Waters, Manchester, UK) equipped with an electrospray ionization (ESI) source, operating in the negative mode. The elution solvent was methanol-acetonitrile (15:85, v/v), at a flow rate of 0.1 mL min −1 . The m/z for betulinic acid was 455.3452, for oleanolic acid 455.3496, and for ursolic acid 455.3365, and the retention times were 6.80, 7.50, and 8.85 min, respectively. The compounds were monitored at 210 nm. All data were obtained in triplicate. The results were expressed as mg/100 g DW.

Determination of Antioxidative Activity
The samples were prepared for analysis as previously described by Lachowicz et al. [15]. The radical scavenging capacity (ABTS) and oxygen radical absorbance capacity (ORAC) methods were used as described by Re et al. [33] and Kapusta et al. [34], respectively. The antioxidative activity was expressed as mmol of Trolox/100 g of DW.

Statistical Analysis
Statistical analysis, one-way ANOVA, and principal component analysis (PCA) were conducted using Statistica version 12.5 (StatSoft, Kraków, Poland). Significant differences (p ≤ 0.05) between mean values were evaluated by one-way ANOVA and Duncan's multiple range test.

Conclusions
In conclusion, the study results provided complete and important information about the bioactive compounds of plants of wild Fallopia japonica Houtt. and Fallopia sachalinensis species that were associated with their antioxidative properties. In addition, the analyzed wild Fallopia species had a similar profile of polyphenols and triterpenoids, but contents of these compounds in leaves, stalks, and roots were different. Generally, the wild Fallopia japonica Houtt. species had a 1.2 times statistically significant higher content of bioactive compounds and antioxidative activity than Fallopia sachalinensis. The leaves were a better source of polymeric procyanidins, phenolic acids, flavones, and flavonols, as well as oleanolic and ursolic acids than the other morphological parts of the tested plants. However, the roots were an excellent source of flavan-3-ols (monomeric and oligomer) and stilbenes, such as resveratrol, and their derivatives. Additionally, plants of wild Fallopia species and their individual parts may be deemed an attractive plant material and, a good source of many substances with a high health-promoting potential. However, further in vivo and in vitro investigations are necessary to confirm interactions between bioactive compounds. The results obtained showed significant differences between wild Fallopia species and their morphological parts, and enabled selecting the most valuable morphological part of the tested plants to be used for food enrichment and nutraceuticals production. Therefore, the leaves seem to the best from the point of view of the food additives to be used as super food and functional food beneficial for health, due to the above-average content of polyphenolic compounds and triterpenoids. In turn, roots, with their high contents of stilbenes and polyphenolic compounds, represent a good material for the medical, pharmaceutical, and cosmetic industries. The principal component analysis of the plants of wild Fallopia species and their morphological parts confirmed significant differences in their chemical composition.