Structural Characterization and Antidepressant-like Effects of Polygonum sibiricum Polysaccharides on Regulating Microglial Polarization in Chronic Unpredictable Mild Stress-Induced Zebrafish.

Polysaccharides are one of the main active ingredients of Polygonum sibiricum (PS), which is a food and medicine homolog used throughout Chinese history. The antidepressant-like effects of PSP and its underlying mechanisms remain elusive, especially the regulation of microglial polarization. The current study determined the chemical composition and structural characteristics of PSP. Then, the chronic unpredictable mild stress (CUMS) procedure was carried out on the zebrafish for 5 weeks, and PSP was immersed for 9 days (1 h/d). The body weight of zebrafish was monitored, and behavioral tests, including the novel tank test and light and dark tank test, were performed to evaluate the antidepressant-like effects of PSP. Then, the function of the hypothalamic-pituitary-interrenal (HPI) axis, the levels of peripheral inflammation, neuronal and blood-brain barrier damage in the mesencephalon and telencephalon, and the mRNA expression of M1/M2 phenotype genes in the brain were examined. PSP samples had the typical structural characteristics of polysaccharides, consisting of glucose, mannose, and galactose, with an average Mw of 20.48 kDa, which presented porous and agglomerated morphologies. Compared with untreated zebrafish, the depression-like behaviors of CUMS-induced zebrafish were significantly attenuated. PSP significantly decreased the levels of cortisol and pro-inflammatory cytokines and increased the levels of the anti-inflammatory cytokines in the body of CUMS-induced depressive zebrafish. Furthermore, PSP remarkably reversed the neuronal and blood-brain barrier damage in the mesencephalon and telencephalon and the mRNA expression of M1/M2 phenotype genes in the brain. These findings indicated that the antidepressant-like effects of PSP were related to altering the HPI axis hyperactivation, suppressing peripheral inflammation, inhibiting neuroinflammation induced by microglia hyperactivation, and modulating microglial M1/M2 polarization. The current study provides the foundations for future examinations of PSP in the functional foods of emotional regulation.

Investigating the Antidepressant Mechanisms of Polygonum sibiricum Polysaccharides via Microglial Polarization.

Polygonum sibiricum, with its medicinal and edibility dual properties, has been widely recognized and utilized throughout Chinese history. As a kind of its effective component, Polygonum sibiricum polysaccharides (PSP) have been reported to be a promising novel antidepressant agent. Meanwhile, the precise mechanisms underlying its action remain elusive. The polarization state transition of microglia is intricately linked to neuroinflammation, indicating its crucial involvement in the pathophysiology of depression. Researchers are vigorously pursuing the exploration of this potential treatment strategy, aiming to comprehend its underlying mechanisms. Hence, the current study was designed to investigate the antidepressant mechanisms of PSP via Microglial M1/M2 Polarization, based on the lipopolysaccharide (LPS)-induced BV2 cell activation model. The results indicate that PSP significantly inhibited NO and LDH release and reduced ROS levels in LPS-induced BV2 cells. PSP could significantly reduce the protein expression level of Iba-1, decreased the mRNA levels of TNF-α, IL-1ß, and IL-6, and increased the mRNA level of IL-10. PSP also significantly reduced the protein expression level of CD16/32 and increased that of CD206, reduced the mRNA level and fluorescence intensity of iNOS, and increased those of Arg-1. However, PSP pretreatment reversed the alterations of the BDNF/TrkB/CREB and Notch/Hes1 pathways in LPS-induced BV2 cells. These results suggested that PSP exerted the anti-inflammatory effects by inhibiting M1 phenotype polarization and promoting microglia polarization toward the M2 phenotype, and its regulation of microglia M1/M2 polarization may be associated with modulating the BDNF/TrkB/CREB and Notch/Hes1 pathways.

Unveiling the immunomodulatory mechanism of polysaccharides from Polygonum cyrtonema based on RNA-seq.

This work aimed to illuminate the mechanism of Polygonatum cyrtonema polysaccharide (PCP-80%) triggered immune activation. Results showed that PCP-80% enhanced the protein expression of COX-2 and iNOS, along with increasing the release of NO, ROS, cytokines (TNF-α, IL-6) in RAW264.7 cells. RNA-seq analysis revealed 2160 differentially expressed genes (DEGs) following PCP-80% treatment, comprising 1142 up-regulated and 1018 down-regulated genes. In addition, for investigating possible regulatory mechanisms, the NF-κB, MAPKs, and JAK-STAT signaling pathways were also chosen based on bioinformatics analysis. Furthermore, these findings were further corroborated through Western blot experiments, validating the activation of JAK-STAT (reduction of JAK1 in cells and elevation of p-STAT3 in the nucleus), MAPK (elevation of p-p38, p-ERK1/2, and p-JNK), and NF-κB (elevation of p-IκBα in cells, reduction of cytoplasmic p65, and increase of nuclear content of p-p65) in macrophage activation induced by PCP-80%. Besides, the production of NO and TNF-α was decreased by the inhibitor of the three pathways. In conclusion, these findings provide strong evidence that PCP-80% effectively modulates the immune response of macrophages, with significant involvement of the JAK-STAT, MAPKs, and NF-κB signaling pathways.

Molecular cloning and in silico analysis of chalcone isomerase from Polygonum minus.

BACKGROUND: Chalcone isomerase (CHI; EC 5.5.1.6) is one of the key enzymes in the flavonoid biosynthetic pathway that is responsible for the intramolecular cyclization of chalcones into specific 2S-flavanones. METHODS AND RESULTS: In this study, the open reading frame (ORF) of CHI was successfully isolated from the cDNA of Polygonum minus at 711-bp long, encoding for 236 amino acid residues, with a predicted molecular weight of 25.4 kDa. Multiple sequence alignment and phylogenetic analysis revealed that the conserved residues (Thr50, Tyr108, Asn115, and Ser192) in the cleft of CHI enzyme group active site are present in PmCHI protein sequence and classified as type I. PmCHI comprises more hydrophobic residues without a signal peptide and transmembrane helices. The three-dimensional (3D) structure of PmCHI predicted through homology modeling was validated by Ramachandran plot and Verify3D, with values within the acceptable range of a good model. PmCHI was cloned into pET-28b(+) plasmid, expressed in Escherichia coli BL21(DE3) at 16 °C and partially purified. CONCLUSION: These findings contribute to a deeper understanding of the PmCHI protein and its potential for further characterization of its functional properties in the flavonoid biosynthetic pathway.

Polygonum orientale L. Alleviates Myocardial Ischemia-Induced Injury via Activation of MAPK/ERK Signaling Pathway.

Although Polygonum orientale L. (PO) has a beneficial effect on treatment of myocardial ischemia (MI), its mechanism remains unclear. This study aimed to explore the pharmacological mechanism of PO against MI through MAPK signaling pathways. Firstly, the therapeutic effect of PO was evaluated for treatment of MI mice. Using Western blot and immunohistochemistry, the influence of PO on MAPK signaling pathways and cell apoptosis was investigated. Subsequently, one key pathway (ERK) of MAPK signaling pathways was screened out, on which PO posed the most obvious impact. Finally, an inhibitor of ERK1/2 was utilized to further verify the regulatory effect of PO on the MAPK/ERK signaling pathway. It was found that PO could reduce the elevation of the ST segment; injury of heart tissue; the activity of LDH, CK, NOS, cNOS and iNOS and the levels of NO, BNP, TNF-α and IL-6. It is notable that PO could significantly modulate the protein content of p-ERK/ERK in mice suffering from MI but hardly had an effect on p-JNK/JNK and p-p38/p38. Additionally, the expressions of bax, caspase3 and caspase9 were inhibited in heart tissue in the PO-treated group. To evaluate whether ERK1/2 inhibitor (PD98059) could block the effect of PO on treatment of MI, both PO and PD98059 were given to mice with MI. It was discovered that the inhibitor indeed could significantly reverse the regulatory effects of PO on the above indicators, indicating that PO could regulate p-ERK/ERK. This study provides experimental evidence that PO extenuates MI injury, cardiomyocyte apoptosis and inflammation by activating the MAPK/ERK signaling pathway.

Polygonum sibiricum polysaccharides exert the antidepressant-like effects in chronic unpredictable mild stress-induced depressive mice by modulating microbiota-gut-brain axis.

Polygonum sibiricum polysaccharides (PSP) are one of the main active components of Polygonatum sibiricum, which is a traditional Chinese medicine with food and drug homologies. Recent studies have revealed the antidepressant-like effects of PSP. However, the precise mechanisms have not been clarified. Therefore, the present study was conducted to explore that whether PSP could exert the antidepressant-like effects via microbiota-gut-brain (MGB) axis in chronic unpredictable mild stress (CUMS)-induced depressive mice by transplantation of fecal microbiota (FMT) from PSP administration mice. FMT markedly reversed the depressive-like behaviors of CUMS-induced mice in the open field, the sucrose preference, the tail suspension, the forced swimming, and the novelty-suppressed feeding tests. FMT significantly increased the levels of 5-hydroxytryptamine and norepinephrine, decreased the levels of the pro-inflammatory cytokines in the hippocampus and reduced the levels of corticosterone, an adrenocorticotropic-hormone, in the serum of CUMS-induced mice. In addition, administration of PSP and FMT significantly increased the expressions of ZO-1 and occludin in the colon and decreased the levels of lipopolysaccharide and interferon-γ in the serum of CUMS-induced mice. Moreover, administration of PSP and FMT regulated the signaling pathways of PI3K/AKT/TLR4/NF-κB and ERK/CREB/BDNF. Taken together, these findings indicated that PSP exerted antidepressant-like effects via the MGB axis.

Photosynthesis-related physiology and metabolomics responses of Polygonum lapathifolium in contrasting manganese environments.

Manganese (Mn) plays an essential role in plant growth; however, excessive Mn is toxic to plants. Polygonum lapathifolium Linn. was tested as a novel Mn-hyperaccumulating species in our previous study, but the underlying mechanisms of this hyperaccumulation are poorly understood. A hydroponic experiment with (8mmolL-1 ) and without additional Mn (CK) was established to explore the possible mechanisms through the effects on photosynthesis-related physiological characteristics and metabolomics. The results showed that additional Mn increased plant biomass, photosynthesis, and stomatal conductance related to increases in the effective photochemical quantum yield of photosystem II and relative electron transport rate (P <0.05). The results from liquid chromatography-mass spectrometry revealed 56 metabolites differentially accumulated between the plants composing these two groups. Metabolites were enriched in 20 metabolic pathways at three levels (environmental information processing, genetic information processing, and metabolism), of which five metabolic pathways were associated with significant or extremely significant changes (P <0.05). These five enriched pathways were ABC transporters (environmental information processing), aminoacyl-tRNA biosynthesis (genetic information processing), biosynthesis of amino acids , d -arginine and d -ornithine metabolism , and arginine biosynthesis (metabolism). Flavonoids may play a key role in Mn tolerance, as they accumulated more than 490-fold, and the relationship between flavonoids and Mn tolerance needs to be studied in the future.

Sesquiterpene from Polygonum barbatum disrupts mitochondrial membrane potential to induce apoptosis and inhibits metastasis by downregulating matrix metalloproteinase and osteopontin in NCI-H460 cells.

Globally, lung cancer accounts for 18% of cancer-associated mortalities. Among the subtypes, non-small cell lung cancer (NSCLC) is the most prevalent. The increased resistance and poor survival rates signify disease aggressiveness and thus require a search for an alternative anticancer molecule. Earlier, the sesquiterpene, i.e., compound 3 ((E)-methyl 6-acetoxy-7-methoxy-1-(2-methylpropylidene)-1H-indene-3-carboxylate) from Polygonum barbatum, was isolated, characterized by us, and reported for preliminary anticancer activity. Therefore, based on these results, this study was designed to explore the underlying molecular mechanism of apoptosis and metastasis against NCI-H460 cells. The molecular mechanism of compound 3 inducing apoptosis and inhibiting metastasis was elucidated by analyzing mitochondrial membrane potential, DNA fragmentation, clonogenic assay, invasion assay, and expression of apoptotic (caspases 3, 6, 8, 9, and BAK) and metastatic markers (MMP 2, MMP 9, and osteopontin). Compound 3 significantly inhibited cell proliferation and induced apoptosis via the intrinsic route, i.e., the mitochondrial pathway, by disrupting mitochondrial membrane potential. The enhanced expression of caspases 6, 9, BAK, and HRK with downregulation of Bcl-2L1 and Ki67 further confirmed the involvement of the intrinsic apoptotic pathway. Moreover, compound 3 restricted the invasive nature of NCI-H460 cells evinced by reduced cell invasion in Boyden chamber invasion assay and downregulating the expression of metastatic markers, i.e., matrix metalloproteinase 2/9 and VEGF. It was also found to block osteopontin by negatively regulating its expression, a marker protein in cancer management. Conclusively, this sesquiterpene exhibited potent anticancer and antimetastatic activity and can be explored further as possible pharmacophores.

In-silico evaluations of the isolated phytosterols from polygonum hydropiper L against BACE1 and MAO drug targets.

Our previous anti-Alzheimer's studies on crude extracts, essential oils and isolated compounds including ß-sitostrol from Polygonum hydropiper L, motivated us for further studies against beta amyloid cleaving enzyme 1 (BACE1) and monoamine oxidases (MAO-A), (MAO-B) enzymes. Before performing detailed studies on the compounds using animal models and immunohistochemistry, molecular docking study was performed against three vital enzymes implicated in several neurological disorders including Alzheimer's disease (AD), Parkinson's disease (PD), depression and anxiety to predict their inhibitory potential against important enzymes. Beta amyloid cleaving enzyme 1 (BACE1) is important enzyme that catalyze pathological amyloidogenic pathway of processing amyloid precursor proteins to form neurotoxic amyloid plaques. Subsequently, BACE1 inhibitors are considered an important tool in the management of AD. MAOs have been categorized in two well-known groups MAO-A and MAO-B, based on their differential affinity for various monoamines substrates. MAO-A has more affinity for norepinephrine and 5-HT, whereas, MAO-B mainly catalyze the breakdown of dopamine and 2-phenylathylamine (PEA) and other monoamines. Subsequently, they have divergent behavioral outcomes and play a significant role in pathophysiology of several neurodegenerative disorders like AD, depression, drug abuse, migraines, schizophrenia, Attention Deficit Disorder (ADD) and Parkinson's disease (PD). Molecular docking was carried out to predict the binding modes of ß-sitosterol and stigmasterol in the binding pockets of BACE1 (beta-sectretase 1) and MAO (monoamine oxidase A, B) enzymes. The 3 D structure of BACE1 (PDB ID: 2QP8), MAO A (PDB ID: 2ZPX) and MAO B (PDB ID: 2XFN) were downloaded from protein databank. The 3 D structures were then subjected to protonation and energy minimization using default parameters of MOE. Three dimensional structures of ß-sitosterol and stigmasterol were built by using Molecular Builder Module program implemented in MOE and saved as a (.mdb) file for molecular docking. Subsequently, the energy of both the compounds were minimized up to 0.05 Gradient using MMFF 94 s force field implemented in MOE. Both the compounds were docked into the active site of proteins using the Triangular Matching docking method (default) and 10 different conformations for each compound were generated. To obtain minimum energy structures the ligands were allowed to be flexible during docking. At the end of docking, the predicted ligand-protein complexes were analyzed for molecular interactions. Overall the docking results showed that these compounds showed good interaction with active site residues of BACE1 as compare to MAO-A and MAO-B. Furthermore, ß-sitosterol showed good interaction with BACE1 as compare to stigmasterol.Communicated by Ramaswamy H. Sarma.

An indigo-producing plant, Polygonum tinctorium, possesses a flavin-containing monooxygenase capable of oxidizing indole.

Polygonum tinctorium (P. tinctorium) is an indigo plant that is cultivated for a specific metabolite that it produces i.e., indoxyl ß-D-glucoside (indican). In this study, flavin-containing monooxygenase (PtFMO) from P. tinctorium was cloned. When recombinant PtFMO was expressed in E. coli in the presence of tryptophan, indigo production was observed. Furthermore, we measured the activity of PtFMO using the membrane fraction from E. coli and found that it could produce indigo using indole as a substrate. The co-expression of PtFMO with indoxyl ß-D-glucoside synthase (PtIGS), which catalyzes the glucosylation of indoxyl, brought about the formation of indican in E. coli. The results showed that indican was synthesized by sequential reactions of PtFMO and PtIGS. In three-week-old P. tinctorium specimens, the first leaves demonstrated higher levels of PtFMO expression than the subsequent leaves. This result coincided with that of our prior study on PtIGS expression level. Our study provides evidence that PtFMO might contribute to indican biosynthesis.

Phenolic Compounds from Polygonum chinense Induce Growth Inhibition and Apoptosis of Cervical Cancer SiHa Cells.

Cervical cancer is considered to be one of the most serious malignant tumors in women. Natural compounds have been considered as important sources in the search for new anticancer agents. Polygonum chinense (PC) has been used as herbal medicine and Chinese cool tea. By activity-guided of the extracts from PC, PCwater shows good growth inhibition on SiHa cell, then by chromatographic analysis (HPLC and HPLC-MS/MS), we found twelve components, seven were phenolic compounds (PHE), two PHE named ellagic acid and corilagin were found to show strong growth inhibition effects in SiHa cell dose-dependently, while the seven phenolic compounds showed low inhibition on the common human HcerEpic cell. Further research found ellagic acid and corilagin induced G2 phase cell cycle arrest by upregulating levels of P53, Bcl-2, caspase 3, and caspase 9, while the Bax was reduced. These results suggested that PHE from PC might have potential anticancer effects against SiHa cells by acting through the apoptosis pathway, PHE from PC might have the potential to be used as a nutraceutical for the prevention and treatment of ovarian cancer.

Production of Antioxidant Molecules in Polygonum aviculare (L.) and Senecio vulgaris (L.) under Metal Stress: A Possible Tool in the Evaluation of Plant Metal Tolerance.

Plants growing on heavy metal (HM)-polluted soils show toxicity symptoms, such as chlorosis and growth reduction, and undergo oxidative stress due to the formation of reactive oxygen species (ROS). Plants overcome oxidative stress by producing a wide range of antioxidant molecules, such as polyphenols and flavonoids. The aim of the present work was to study the accumulation of these molecules in response to increasing concentrations of Cd, Cr, Cu, Ni, Pb and Zn and to assess whether they can be used as a tool in assessing metal-related stress in Polygonum aviculare and Senecio vulgaris. On average, P. aviculare shoots accumulated lower amounts of metals than S. vulgaris shoots. The uptake of all six elements was correlated and proportional to their concentration in the nutrient solution (ρ > 0.9), with the bioaccumulation factor (BAF) being >1 for most of them. The present research demonstrated that 82% of the samples showed a good correlation (|ρ| > 0.5) between the level of polyphenols, flavonoids and antioxidant activity and the metal concentration in plant shoots, confirming that the metal stress level and production of phenolic compounds having antioxidant activity were strictly connected. Nonetheless, the mere quantification of these molecules cannot identify the type of metal that caused the oxidative stress, neither determine the concentration of the stressors. The five tested populations of each species did not show any specific adaptation to the environment of origin.

Ethyl acetate fraction of flavonoids from Polygonum hydropiper L. modulates pseudorabies virus-induced inflammation in RAW264.7 cells via the nuclear factor-kappa B and mitogen-activated protein kinase pathways.

Pseudorabies virus (PRV) infection leads to severe inflammatory responses and tissue damage, and many natural herbs exhibit protective effects against viral infection by modulating the inflammatory response. An ethyl acetate fraction of flavonoids from Polygonum hydropiper L. (FEA) was prepared through ethanol extraction and ethyl acetate fractional extraction. An inflammatory model was established in RAW264.7 cells with PRV infection to evaluate the anti-inflammatory activity of FEA by measuring cell viability, nitric oxide (NO) production, reactive oxygen species (ROS) release, and mRNA expression of inflammatory factors, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Its functional mechanism was investigated by analyzing the phosphorylation and nuclear translocation of key proteins in the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Our findings indicate that PRV induced inflammatory responses in RAW264.7 cells, and the responses were similar to that in lipopolysaccharide (LPS)-stimulated cells. FEA significantly suppressed NO synthesis and down-regulated both expression and secretion of COX-2, iNOS, and inflammatory cytokines (P<0.05 or P<0.01). FEA also reduced NF-κB p65 translocation into the nucleus and decreased MAPK phosphorylation, indicating that the NF-κB/MAPK signaling pathway may be closely related to the inflammatory response during viral infection. The findings suggested the potential pharmaceutical application of FEA as a natural product that can treat viral infections due to its ability to mitigate inflammatory responses.

Characterization and antioxidant activity of the oligo-maltose fraction from Polygonum Cillinerve.

In this study, Polygonum Cillinerve polysaccharide (PCP) was extracted, and characterized by high performance gel permeation chromatography, high performance liquid chromatography, fourier transform infrared spectroscopy, nuclear magnetic resonance and mass spectroscopy. The results showed that PCP was composed of glucose, it was α-D-glucan and the backbone of PCP was consisted of repeating units of (1→4)-α-D-Glucose. In addition, the antioxidant potential of PCP was assessed in vitro. The results showed that PCP had strong hydroxyl radical scavenging ability, some DPPH scavenging ability and good reducing power. Moreover, the results of the enzyme-linked immunosorbent assays showed that PCP at 15.625-0.975 µg/mL could significantly improve the level of superoxide dismutase and glutathione peroxidase, and could significantly decrease the level of myeloperoxidase, malondialdehyde and xanthine oxidase in macrophages. These results indicated that PCP could potentially be developed as a natural antioxidant.

A Study on Tissue-Specific Metabolite Variations in Polygonum cuspidatum by High-Resolution Mass Spectrometry-Based Metabolic Profiling.

Polygonum cuspidatum Sieb. et Zucc. is a traditional Chinese herbal medicine widely used to treat tussis, hepatitis and arthralgia. This study identified and quantitatively described the bioactive compounds in different P. cuspidatum tissues. Metabolic profiles of root, stem, leaf, flower, rhizome and seed were determined using high-resolution mass spectrometry in combination with multivariate analyses. In total, 53 metabolites, 8 reported for the first time in this species, were putatively identified and classified mainly as stilbenes, anthraquinones and flavonoids. A principal component analysis, cluster analysis and heatmap were used to depict the correlations between specimens and the relative abundance levels of these compounds in different plant tissues. An orthogonal partial least square discriminant analysis found that 13 metabolites showed distinct differences among the six plant tissues, making them potential discriminative tissue-identification markers. This study will provide guidance in comparing, selecting and exploiting the medicinal uses of different P. cuspidatum tissues.

The effects of EDTA on plant growth and manganese (Mn) accumulation in Polygonum pubescens Blume cultured in unexplored soil, mining soil and tailing soil from the Pingle Mn mine, China.

The effects of water-extractable Mn concentration, bioaccumulation factor (BAF), translocation factor (TF), and Mn uptake by Polygonum pubescens Blume cultured in the unexplored soil, mining soil and tailing soil from the Pingle Mn mine in China were quantified in a pot experiment to determine the effects of EDTA exposure on the success of phytoremediation. The results showed that EDTA significantly (P < 0.05) increased the water-extractable Mn concentration, and soils with different amounts of artificial disturbances had different responses to EDTA exposure. Low and medium EDTA concentrations might have positive effect on plant growth of P. pubescens cultured in the unexplored soil, as indicated by comparable increases in biomass, plant height and photosynthetic pigment content, but opposite results were found with high EDTA concentrations exposure. EDTA exposure had a negative effect on the growth of P. pubescens cultured in the mining soil and tailing soil. In general, the concentration of Mn in different tissues significantly (P < 0.05) increased as the EDTA concentration increased in each soil. The efficacy of Mn remediation by P. pubescens was enhanced in all three soils, with all EDTA treatments.

Phytoremediation of Mn-contaminated paddy soil by two hyperaccumulators (Phytolacca americana and Polygonum hydropiper) aided with citric acid.

The purpose of this study was to investigate the phytoremediation potential of two hyperaccumulator plants, Phytolacca americana L. and Polygonum hydropiper L., on manganese-contaminated paddy soils. The biomass growth, Mn concentrations in plant tissues, and potential Mn removal efficiency from soils of these two plants were studied with citric acid, and the mechanisms of citric acid on these two plants were analyzed by examining the root activity, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in leaves, as well as the concentrations of O2·- and H2O2 in leaves. The results showed that the biomass of these two plants were both promoted under low level of citric acid (3 mmol kg-1). The concentration of Mn in the plants and the amount of Mn removed from the soil by the plants through harvesting were enhanced at low and intermediate (10 mmol kg-1) citric acid application levels. The results also showed that root activity was enhanced at the low citric acid level and significantly inhibited under the intermediate and high levels (15 mmol kg-1), which indicates the facilitative function of the low level of citric acid and the inhibitive function of the high level of citric acid application on plant biomass growth. Under the low and intermediate levels of citric acid application, O2·- in the plant leaves increased sharply, and the SOD, POD, and CAT activities also increased sharply, which made the level of H2O2 very similar to that of the control, ensuring the health of the plants. At the high level of citric acid application, however, the O2·- continued to rise sharply, while the activity of the three antioxidant enzymes declined sharply, causing the concentration of hydrogen peroxide to be much higher than that in the control, thus endangering the plants. The present study shows the potential of P. hydropiper for use in the phytoremediation of soil contaminated with a relatively low level of manganese.

Subcellular distribution and chemical form of phosphorus involved in alleviating phosphorus toxicity of the phosphorus-accumulator Polygonum hydropiper.

Polygonum hydropiper is a dominant plant species in Shifang phosphorus (P) mine area and is a promising P-accumulator used for P-phytoextraction. To date, little information is available on the physiological response involved in alleviating P toxicity of P. hydropiper under high P. A pot experiment was carried out to investigate growth, P subcellular distribution, chemical forms in two ecotypes of P. hydropiper under high levels (1, 4, and 8 mmol P L-1) of inorganic P (Pi) and organic P (Po), supplied as KH2PO4 and myo-inositol hexaphosphoric acid dodecasodium salt, respectively. The mining ecotype (ME) showed a greater ability to tolerate high P than the non-mining ecotype (NME), as shown by its superior growth with undamaged leaf anatomical structure. The ME showed 1.3-2.2 times greater shoot P accumulation than the NME. More than 93% of P accumulated in tissue cell wall and soluble fraction. The increasing P treatments increased all tissue P forms, especially Pi form. The ME showed significantly higher ester P, nucleic P and insoluble P in tissues than the NME at 8 mmol L-1; however, it demonstrated lower Pi, expect for roots at 5 weeks. The percentages of Pi and nucleic P in roots of the ME were higher than other P forms, and the percentages of nucleic P dominated in the leaves. Probably, the combination of preferential distribution of P in cell wall and soluble fraction in tissues and storage of P in low activity as nucleic P in leaves allows the ME to adapt high P.

The natural compound 2,3,5,4'-tetrahydroxystilbene-2-O-ß-d glucoside protects against adriamycin-induced nephropathy through activating the Nrf2-Keap1 antioxidant pathway.

2,3,5,4'-Tetrahydroxystilbene-2-O-ß-d-glucoside (THSG) is an active compound extracted from Polygonum multiflorum Thunb. This herb and radix Polygoni Multiflori preparata have been used to treat arteriosclerosis, hyperlipidemia, hypercholesterolemia, and diabetes for thousands of years. This study aimed to investigate the protective effects of THSG in an Adriamycin (AD)-induced focal segmental glomerulosclerosis (FSGS) mouse model and the underlying mechanisms in an in vitro system. Mice were treated with THSG (2.5 and 10 mg/kg, oral gavage) for 24 consecutive days. On the third day, mice were intravenously given a single dose of AD (10 mg/kg). At the end of the experiment, plasma and kidney samples were harvested to evaluate the therapeutic effects of THSG. The potential mechanisms of THSG in protecting against AD-induced cytotoxicity were examined using a real-time polymerase chain reaction, immunoblots, lactate dehydrogenase assay, and a cellular oxidized-thiol detection system in a mouse mesangial cell line. In this study, THSG showed concentration-dependent protective effects in ameliorating the progression of AD-induced FSGS. THSG suppressed albuminuria and hypercholesterolemia and reduced the status of lipid peroxidation in urine, plasma, and kidney tissue samples. Furthermore, THSG protected against podocyte damage, reduced renal fibrotic gene expressions, and alleviated the severity of glomerulosclerosis. Treatment of mouse mesangial cells with THSG induced nuclear factor erythroid-derived 2-like 2 (Nrf2) nuclear translocation, increased heme oxygenase-1 and NAD(P)H:quinone oxidoreductase (NQO)-1 gene expressions, and reduced cellular thiol oxidation and resistance to AD-induced cytotoxicity. Silencing Nrf2 and its repressor protein, Kelch-like ECH-associated protein 1 (Keap1), abolished these protective effects of THSG. In conclusion, THSG can play a protective role in ameliorating the progression of FSGS in a mouse model through activation of the Nrf2-Keap1 antioxidant pathway. Although a well-designed therapeutic study is needed, THSG may be applied to manage chronic kidney disease.

Feed additive production by fermentation of herb Polygonum hydropiper L. and cassava pulp with simultaneous flavonoid dissolution.

Fermentation of herb Polygonum hydropiper L. (PHL) and cassava pulp (CP) for feed additive production with simultaneous flavonoid dissolution was investigated, and a two-stage response surface methodology (RSM) based on Plackett-Burman factorial design (PB design) was used to optimize the flavonoid dissolution and protein content. Using the screening function of PB design, four different significant factors for the two response variables were acquired: factors A (CP) and B (PHL) for the flavonoid dissolution versus factors G (inoculum size) and H (fermentation time) for protein content. Then, two RSMs were used sequentially to improve the values of the two response variables separately. The mutual corroboration of the experimental results in the present study confirmed the validity of the associated experimental design. The validation experiment showed a flavonoid dissolution rate of 94.00%, and a protein content of 18.20%, gaining an increase in 21.20% and 199.10% over the control, respectively. The present study confirms the feasibility of feed additive production by Saccharomyces cerevisiae with CP and PHL and simultaneous optimization of flavonoid dissolution and protein content using a two-stage RSM.