Two-dimensional thin-layer chromatography of selected Polygonum sp. extracts on polar-bonded stationary phases

Screening and Evaluation of Dermo-Cosmetic Activities of the Invasive Plant Species Polygonum cuspidatum

Polygonum cuspidatum (P. cuspidatum) is among the world's most problematic invasive plant species with negative ecological, socio-economic and security consequences. Management operations in areas invaded systematically generate a large quantity of plant waste, most often without outlets. Using this plant material could constitute a new alternative treatment for sustainable management. P. cuspidatum is well known to have numerous biological properties, containing notably stilbenes, quinones, flavonoids and phenolic acids. The present work proposes a reliable strategy using powerful techniques for the screening and the evaluation of the dermo-cosmetic potential of its aerial parts (AP) and root parts (RP). To the best of our knowledge, only antioxidant and anti-tyrosinase activities were previously evaluated on P. cuspidatum among the targets studied (superoxide dismutase, hyaluronidase, elastase, collagenase and tyrosinase). The results revealed strong antioxidant and anti-collagenase activities, moderate anti-hyaluronidase activity, while weak anti-elastase and anti-tyrosinase activities were observed for ethanolic extracts. Different standards selected and screened on the same targets made it possible to correlate the observed residual activities of produced extracts of P. cuspidatum from Savoie Mont Blanc and their chemical compositions. A structure-activity study was thus conducted on main molecular families, widely represented in the genus Polygonum.

(-)-Epicatechin-An Important Contributor to the Antioxidant Activity of Japanese Knotweed Rhizome Bark Extract as Determined by Antioxidant Activity-Guided Fractionation

The antioxidant activities of Japanese knotweed rhizome bark extracts, prepared with eight different solvents or solvent mixtures (water, methanol, 80% methanol_(aq), acetone, 70% acetone_(aq), ethanol, 70% ethanol_(aq), and 90% ethyl acetate_(aq)), were determined using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay. Low half maximal inhibitory concentration (IC₅₀) values (2.632–3.720 µg mL⁻¹) for all the extracts were in the range of the IC₅₀ value of the known antioxidant ascorbic acid at t₀ (3.115 µg mL⁻¹). Due to the highest extraction yield (~44%), 70% ethanol_(aq) was selected for the preparation of the extract for further investigations. The IC₅₀ value calculated for its antioxidant activity remained stable for at least 14 days, while the IC₅₀ of ascorbic acid increased over time. The stability study showed that the container material was of great importance for the light-protected storage of the ascorbic acid_(aq) solution in a refrigerator. Size exclusion–high-performance liquid chromatography (SEC-HPLC)–UV and reversed phase (RP)-HPLC-UV coupled with multistage mass spectrometry (MSⁿ) were developed for fractionation of the 70% ethanol_(aq) extract and for further compound identification, respectively. In the most potent antioxidant SEC fraction, determined using an on-line post-column SEC-HPLC-DPPH assay, epicatechin, resveratrol malonyl hexoside, and its in-source fragments (resveratrol and resveratrol acetyl hexoside) were tentatively identified by RP-HPLC-MSⁿ. Moreover, epicatechin was additionally confirmed by two orthogonal methods, SEC-HPLC-UV and high-performance thin-layer chromatography (HPTLC) coupled with densitometry. Finally, the latter technique enabled the identification of (−)-epicatechin. (−)-Epicatechin demonstrated potent and stable time-dependent antioxidant activity (IC₅₀ value ~1.5 µg mL⁻¹) for at least 14 days.

Off-line multidimensional high performance thin-layer chromatography for fractionation of Japanese knotweed rhizome bark extract and isolation of flavan-3-ols, proanthocyanidins and anthraquinones

A methodology based on off-line multidimensional thin-layer chromatography was developed for isolation of several secondary metabolites from bark of Japanese knotweed (Fallopia japonica Houtt.) rhizomes. Successive fractionation steps using PLC silica gel and HPTLC silica gel or HPTLC cellulose plates in combination with various developing solvents enabled isolation of (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, procyanidin B1, procyanidin B2, procyanidin B3, proanthocyanidin B dimer gallate, emodin, emodin-8-O-glucoside and emodin-8-O-malonyl-glucoside. Their identity was confirmed by HPTLC, HPTLC-MSⁿ and for most of them also by ¹H NMR and 2D NMR analyses. To the best of our knowledge emodin-8-O-malonyl-glucoside, procyanidins B1 and B2 were for the first time isolated from this plant material. HPTLC and HPTLC-MSⁿ analyses were also performed as support of fractionation/isolation process, leading to first detection of some compounds in bark of Japanese knotweed rhizomes and Japanese knotweed rhizomes in general: procyanidins B1 and B2, methyl derivatives of emodin bianthrone and emodin bianthrone-hexose, resveratrol-malonyl-hexoside and taxifolin derivatives. Characterization of flavan-3-ols and proanthocyanidins was facilitated by post-chromatographic derivatization of the corresponding chromatographic zones with 4-dimethylaminocinnamaldehyde (DMACA) detection reagent.

Ultraviolet-B acclimation is supported by functionally heterogeneous phenolic peroxidases

Tobacco plants were grown in plant chambers for four weeks, then exposed to one of the following treatments for 4 days: (1) daily supplementary UV-B radiation corresponding to 6.9 kJ m-2 d-1 biologically effective dose (UV-B), (2) daily irrigation with 0.1 mM hydrogen peroxide, or (3) a parallel application of the two treatments (UV-B + H2O2). Neither the H2O2 nor the UV-B treatments were found to be damaging to leaf photosynthesis. Both single factor treatments increased leaf H2O2 contents but had distinct effects on various H2O2 neutralising mechanisms. Non-enzymatic H2O2 antioxidant capacities were increased by direct H2O2 treatment only, but not by UV-B. In contrast, enzymatic H2O2 neutralisation was mostly increased by UV-B, the responses showing an interesting diversity. When class-III peroxidase (POD) activity was assayed using an artificial substrate (ABTS, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)), both treatments appeared to have a positive effect. However, only UV-B-treated leaves showed higher POD activities when phenolic compounds naturally occurring in tobacco leaves (chlorogenic acid or quercetin) were used as substrates. These results demonstrate a substrate-dependent, functional heterogeneity in POD and further suggest that the selective activation of specific isoforms in UV-B acclimated leaves is not triggered by excess H2O2 in these leaves.

Leaves of Invasive Plants-Japanese, Bohemian and Giant Knotweed-The Promising New Source of Flavan-3-ols and Proanthocyanidins

This is the first report on identification of all B-type proanthocyanidins from monomers to decamers (monomers—flavan-3-ols, dimers, trimers, tetramers, pentamers, hexamers, heptamers, octamers, nonamers, and decamers) and some of their gallates in leaves of Japanese knotweed (Fallopia japonica Houtt.), giant knotweed (Fallopia sachalinensis F. Schmidt) and Bohemian knotweed (Fallopia × bohemica (Chrtek & Chrtkova) J.P. Bailey). Flavan-3-ols and proanthocyanidins were investigated using high performance thin-layer chromatography (HPTLC) coupled to densitometry, image analysis, and mass spectrometry (HPTLC–MS/MS). All species contained (−)-epicatechin and procyanidin B2, while (+)-catechin was only detected in Bohemian and giant knotweed. (−)-Epicatechin gallate, procyanidin B1 and procyanidin C1 was only confirmed in giant knotweed. Leaves of all three knotweeds have the same chemical profiles of proanthocyanidins with respect to the degree of polymerization but differ with respect to gallates. Therefore, chromatographic fingerprint profiles of proanthocyanidins enabled differentiation among leaves of studied knotweeds, and between Japanese knotweed leaves and rhizomes. Leaves of all three species proved to be a rich source of proanthocyanidins (based on the total peak areas), with the highest content in giant and the lowest in Japanese knotweed. The contents of monomers in Japanese, Bohemian and giant knotweed were 0.84 kg/t of dry weight (DW), 1.39 kg/t DW, 2.36 kg/t, respectively, while the contents of dimers were 0.99 kg/t DW, 1.40 kg/t, 2.06 kg/t, respectively. Giant knotweed leaves showed the highest variety of gallates (dimer gallates, dimer digallates, trimer gallates, tetramer gallates, pentamer gallates, and hexamer gallates), while only monomer gallates and dimer gallates were confirmed in Japanese knotweed and monomer gallates, dimer gallates, and dimer digallates were detected in leaves of Bohemian knotweed. The profile of the Bohemian knotweed clearly showed the traits inherited from Japanese and giant knotweed from which it originated.

Depressor effect of the young leaves of Polygonum hydropiper Linn. in high-salt induced hypertensive mice

A novel chymase inhibitor has been reported to have depressor effect in salt-induced hypertension. Therefore, we examined the hypothesis that chymase inhibitory dried young leaves of Polygonum hydropiper (PPH) or young leaves extract of Polygonum hydropiper (PHE) could reduce salt-induced hypertension. In this study, 8-wk old wild-type mice were allocated into three experiments and experiment I included groups, I- normal water drinking, II- high salt (2% NaCl) water (HSW) drinking, and III- HSW plus PPH (500 mg kg^-1, orally) for 12-wk. Blood pressure (BP) and heart rate (HR) were measured at baseline and weekly up to wk-12. In experiment II, mice were given HSW for 12-wk followed by 8-wk treatment with PPH plus HSW (62.5, 125, 250 and 500 mg kg^-1 for groups I, II, III and IV, respectively). BP and HR were measured at baseline and monthly until wk-12, following weekly for 8-wk. Experiment III comprised of four groups of mice for 12-wk HSW and 8-wk treatment with PHE plus HSW (2.5, 5, 10 and 20 mg kg^-1 for groups I-IV, respectively). BP and HR were measured at baseline and monthly up to wk-12, following weekly for 8-wk. Significant reduction in BP and HR were observed in mice treated with PPH (500 mg kg^-1) compared to HSW control. PPH reduced BP and HR dose dependently in hypertensive mice and the higher dose showed maximum reduction. PHE at its maximum dose (20 mg kg^-1) significantly suppressed BP and HR. Over all, we found that the young leaves of Polygonum hydropiper suppressed salt-induced hypertension.

High performance thin-layer chromatography-mass spectrometry of Japanese knotweed flavan-3-ols and proanthocyanidins on silica gel plates

On-line elution based TLC-MS is now a well-established technique, but the quality of the data obtained can sometimes be hampered by a severe spectral background or by strong ion suppression, especially when silica gel plates are used in combination with an acidic modifier in the developing solvent. We solved this issue simply and efficiently using two pre-developments of the plates, firstly with methanol-formic acid (10:1, v/v) and secondly with acetonitrile-methanol (2:1, v/v). This solution resulted in significant improvement in the sensitivity of HPTLC-MS methods. The applicability of this approach was proven on analysis of flavan-3-ols and proanthocyanidins in crude extracts of Japanese knotweed (Fallopia japonica Houtt.) rhizomes. Separations on HPTLC silica gel and HPTLC silica gel MS grade plates using developing solvents toluene-acetone-formic acid (3:3:1, 6:6:1, 3:6:1, v/v) and dichloromethane-acetone-formic acid (1:1:0.1, v/v) were followed by post-chromatographic derivatization with 4-dimethylaminocinnamaldehyde (DMACA) detection reagent. Examination of the stability of the analytes on the start confirmed that the plates should be developed immediately after the application of standards and sample test solutions. In a five hours stability testing after development we discovered an unexpected phenomenon of enhanced absorption at 280nm. However, based on an experiment with post-chromatographic derivatization with DMACA detection reagent, the analytes were proven to be sufficiently stable in the time frame of an HPTLC-MS analysis. This was important for development of the first HPTLC-MS and HPTLC-MSⁿ methods for identification of flavan-3-ols and B-type proanthocyanidins from monomers up to decamers. For the first time, based on this research methodology, trimers, trimer gallates, tetramer gallates, pentamers, pentamer gallates, hexamers, hexamer gallates, heptamers, octamers, nonamers and decamers were tentatively identified in Japanese knotweed rhizomes. Additionally, all developed HPTLC-MS methods have enabled simultaneous identification of stilbenes (resveratrol, piceatannol hexoside, piceid) and anthraquinones (emodin, emodin-O-hexoside, emodin-O-(acetyl)-hexoside and emodin-O-(6'-O-malonyl)-hexoside).

Flavonoids of Polygonum hydropiper L. attenuates lipopolysaccharide-induced inflammatory injury via suppressing phosphorylation in MAPKs pathways

Background

Polygonum hydropiper L. is widely used as a traditional remedy for the treatment of dysentery, gastroenteritis. It has been used to relieve swelling and pain, dispel wind and remove dampness, eliminate abundant phlegm and inflammatory for a long time. Previous study showed that antioxidants especially flavonoids pretreatment alleviated sepsis-induced injury in vitro and in vivo. In the present study, the possible anti-inflammatory effect of flavonoids from normal butanol fraction of Polygonum hydropiper L. extract (FNP) against inflammation induced by lipopolysaccharide (LPS) was evaluated in vivo and in vitro.

Methods

The content of total flavonoid of FNP was determined by the aluminum colorimetric method. The content of rutin, quercetin and quercitrin was determined by HPLC method. Mice received FNP orally 3 days before an intra-peritoneal (i.p.) injection of lipopolysaccharide (LPS). Total superoxidase dismutase (T-SOD), total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), glutathione (GSH), myeloperoxidase (MPO) and malondialdehyde (MDA) levels were measured. Tumor necrosis factor-α levels in serum and tissue was measured. mRNA expressions of pro-inflammatory cytokines in lung were assessed by Real-Time PCR. Histopathological changes were evaluated in lung, ileum and colon. We also investigated FNP on reactive oxygen species (ROS), nitric oxide (NO) and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8) production, inducible nitric oxide synthase (iNOS), Cyclooxygenase-2 (COX-2) protein expression, phosphorylation of MAPKs and AMPK in LPS-stimulated RAW264.7 cells.

Results

FNP increased the levels of T-SOD, T-AOC, GSH-PX and GSH, decreased the levels of TNF-α, MPO and MDA, attenuate the histopathological lesion in LPS-stimulated mice. FNP inhibited production of inflammatory cytokines, ROS and NO, protein expressions of iNOS and COX-2, phosphorylation of ERK, JNK and c-JUN in MAPKs, promoted phosphorylation of AMPKα suppressed by LPS.

Conclusion

These results suggested in vivo anti-inflammatory activities of FNP might contributed to its enhancement in antioxidant capacity, its inhibitory effects may be mediated by inhibiting the phosphorylation of JNK, ERK and c-JUN in MAPKs signaling pathways.

Ethnobotanical, Phytochemical, Pharmacological, and Toxicological Aspects of Persicaria hydropiper (L.) Delarbre

Persicaria hydropiper (L.) Delarbre, belonging to Polygonaceae family, is a common weed found in most of the temperate countries including Bangladesh, China, Malaysia, and Japan. The plant is also referred to as “marsh pepper” or “smart weed.” It appears to be a useful herb with evidence-based medicinal properties. The present work addresses the botanical description, traditional uses, phytochemistry, pharmacology, and toxicology of P. hydropiper. All plant parts have been commonly used in the traditional systems of medicines. Flavonoids are the major group of phytochemical components followed by drimane-type sesquiterpenes and sesquiterpenoids, as well as phenylpropanoids. Different extracts and plant parts showed remarkable pharmacological activities including antioxidant, antibacterial, antifungal, antihelminth, antifeedant, cytotoxicity, anti-inflammatory, antinociceptive, oestrogenicity, antifertility, antiadipogenicity, and neuroprotection. Mutagenicity and acute and subchronic toxicities of the plant were also reported. P. hydropiper has tremendous medicinal properties that could further be investigated for the development of evidence-based herbal products.

Micro-TLC Approach for Fast Screening of Environmental Samples Derived from Surface and Sewage Waters

In this work we demonstrated analytical capability of micro-planar (micro-TLC) technique comprising one and two-dimensional (2D) separation modes to generate fingerprints of environmental samples originated from sewage and ecosystems waters. We showed that elaborated separation and detection protocols are complementary to previously invented HPLC method based on temperature-dependent inclusion chromatography and UV-DAD detection. Presented 1D and 2D micro-TLC chromatograms of SPE (solid-phase extraction) extracts were optimized for fast and low-cost screening of water samples collected from lakes and rivers located in the area of Middle Pomerania in northern part of Poland. Moreover, we studied highly organic compounds loaded in the treated and untreated sewage waters obtained from municipal wastewater treatment plant "Jamno" near Koszalin City (Poland). Analyzed environmental samples contained number of substances characterized by polarity range from estetrol to progesterone as well as chlorophyll-related dyes previously isolated and pre-purified by simple SPE protocol involving C18 cartridges. Optimization of micro-TLC separation and quantification protocols of such samples were discussed from the practical point of view using simple separation efficiency criteria including total peaks number, log(product ΔhR_F), signal intensity and peak asymmetry. Outcomes of the presented analytical approach, especially using detection involving direct fluorescence (UV366/Vis) and phosphomolybdic acid (PMA) visualization are compared with UV-DAD HPLC-generated data reported previously. Chemometric investigation based on principal components analysis revealed that SPE extracts separated by micro-TLC and detected under fluorescence and PMA visualization modes can be used for robust sample fingerprinting even after long-term storage of the extracts (up to 4 years) at subambient temperature (-20 °C). Such approach allows characterization of wide range of sample components that are present in given extract in high and middle concentration range. Due to protocol simplicity and low cost of analysis this method can be useful for preliminary sample screening.

Micro 2D-TLC of Selected Plant Extracts in Screening of Their Composition and Antioxidative Properties

Micro two-dimensional separations were performed on polar bonded stationary phases of the type cyanopropyl-silica using non-aqueous eluents (polar modifier dissolved in n-heptane) as the first direction eluents and aqueous eluents (organic modifier-MeOH dissolved in water) as the second direction eluents. The chromatographic process was performed in micro scale using 5 × 5 cm plates, small volumes of eluents and 10 μL of plant extracts to obtain satisfying separation. Plates developed in horizontal chambers were dried and observed in UV light (254 nm and 366 m) photographed by digital camera and derivatized by DPPH to detect antioxidants (free radical scavengers) or derivatized by Naturstoff reagent to detect phenolic compounds (characteristic luminescence of some phenolic compounds). The above experiments give the possibility to construct fingerprints for investigated Polygonum hydropiper, Betula verrucosa and Pulmonaria officinalis extracts. It can be used in quality control of the plant material and its antioxidative activity. Novelty of the paper is the micro-scale of the separation by two-dimensional thin layer chromatography mode. For the first time two-dimensional separation of plant extracts on 5 × 5 cm plates in two directions is performed.

Biological Fingerprinting of Herbal Samples by Means of Liquid Chromatography

Biological chromatographic fingerprinting is a relatively new concept in the quality control of herbal samples. Originally it has been developed with the application of HPLC, and recently herbal samples' biological profiles have been obtained by means of thin-layer chromatography (TLC). This paper summarizes the application of liquid chromatographic techniques for the purpose of biological fingerprint analysis (BFA) of complex herbal samples. In case of biological TLC fingerprint, which is a relatively novel solution, perspectives of its further development are outlined in more detail. Apart from already published data, some novel results are also shown and briefly discussed. The paper aims at drawing scientists' attention to the unique solutions offered by biological fingerprint construction.

Approach to develop a standardized TLC-DPPH• test for assessing free radical scavenging properties of selected phenolic compounds

TLC-DPPH(•) test belongs to a group of frequently performed assays aimed at detection of compounds with desired activity (effect directed analysis). Despite its popularity a standard procedure has not been elaborated so far causing difficulties in comparing results obtained in different laboratories. Thus the aim of the presented research was an approach to develop a standardized procedure for assessing free radical scavenging properties of plant polyphenols. It was observed that specifically positive adsorbent (silica gel) strengthened the observed result of radical-antioxidant reaction, while polar bonded stationary phase CN-silica weakened it. Based on the observed results it was concluded that the TLC-DPPH(•) assay should be preferably performed on the surface of non-specific adsorbents (e.g.: RP-18) with the use of n-hexane for DPPH(•) dissolution. It is also proposed to document the results every 5 min after staining, as they change in time.