A chromosome-level genome reveals genome evolution and molecular basis of anthraquinone biosynthesis in Rheum palmatum.

BACKGROUND: Rhubarb is one of common traditional Chinese medicine with a diverse array of therapeutic efficacies. Despite its widespread use, molecular research into rhubarb remains limited, constraining our comprehension of the geoherbalism. RESULTS: We assembled the genome of Rheum palmatum L., one of the source plants of rhubarb, to elucidate its genome evolution and unpack the biosynthetic pathways of its bioactive compounds using a combination of PacBio HiFi, Oxford Nanopore, Illumina, and Hi-C scaffolding approaches. Around 2.8 Gb genome was obtained after assembly with more than 99.9% sequences anchored to 11 pseudochromosomes (scaffold N50 = 259.19 Mb). Transposable elements (TE) with a continuous expansion of long terminal repeat retrotransposons (LTRs) is predominant in genome size, contributing to the genome expansion of R. palmatum. Totally 30,480 genes were predicted to be protein-coding genes with 473 significantly expanded gene families enriched in diverse pathways associated with high-altitude adaptation for this species. Two successive rounds of whole genome duplication event (WGD) shared by Fagopyrum tataricum and R. palmatum were confirmed. We also identified 54 genes involved in anthraquinone biosynthesis and other 97 genes entangled in flavonoid biosynthesis. Notably, RpALS emerged as a compelling candidate gene for the octaketide biosynthesis after the key residual screening. CONCLUSION: Overall, our findings offer not only an enhanced understanding of this remarkable medicinal plant but also pave the way for future innovations in its genetic breeding, molecular design, and functional genomic studies.

Transcriptomic divergence of the Rheum palmatum complex derived from top-geoherb and non-geoherb areas provides the insights into geoherbalism properties of rhubarb.

Geoherb usually represents high-quality medicinal herbs with better clinical therapeutic effects, and elucidating the geoherbalism is essential for the quality improvement of traditional Chinese Medicine. However, few researches were conducted to clarify the geoherbalism based on a large scale of transcriptomics. In the present study, we compared the transcriptomes of Rheum palmatum complex derived from top-geoherb and non-geoherb areas to show the geoherbalism properties of rhubarb. A total of 412.32 Gb clean reads were obtained with unigene numbers of 100,615 after assembly. Based on the obtained transcriptome datasets, key enzyme-encoding genes involved in the anthraquinones biosynthesis were also obtained. We also found that 21 anthraquinone-related unigenes were differentially expressed between two different groups, and some of these DEGs were correlated to the content accumulation of five free anthraquinones, indicating that the gene expression profiles may promote the geoherbalism formation of rhubarb. In addition, the selective pressure analyses indicated that most paired orthologous genes between these two groups were subject to negative selection, and only a low proportion of orthologs under positive selection were detected. Functional annotation analyses indicated that these positive-selected genes related to the functions such as gene expression, substance transport, stress response and metabolism, indicating that discrepant environment also enhanced the formation of geoherbalism. Our study not only provided insights for the genetic mechanism of geoherbalism of rhubarb, but also laid more genetic cues for the future rhubarb germplasms improvement and utilization.

Application of two-dimensional reversed phase countercurrent chromatography × high-performance liquid chromatography to bioactivity-guided screening and isolation of α-glucosidase inhibitors from Rheum palmatum L.

In the present work, comprehensive two-dimensional reversed-phase countercurrent chromatography × reversed-phase liquid chromatography combined (2D RPCCC × RPLC) with 2D microfraction bioactive evaluation was employed to screen and isolate α-glucosidase inhibitors from Rheum palmatum L. Countercurrent chromatography was employed to improve 2D analysis and preparative separation. A selected biphasic solvent system composed of petroleum ether/ethyl acetate/methanol/water with gradient elution mode was used for the first dimension RPCCC separation (1D RPCCC). Solid-phase extraction was applied to eliminate interfering polar compounds before the second dimension analysis (2D RPLC). 76 components were shown in 2D contour plot in UV 280 nm. 11 Candidates were separated by a scaled-up CCC and identified by 1H NMR and 13C NMR, including anthraquinones, flavonoids, stilbenes, phenols, and glucoside derivatives. In addition, it was found that two components, resveratrol-4'-O-(6″-galloyl)glucoside (36) and lyciumaside (43) were identified as natural α-glucosidase inhibitors in Rheum palmatum L. for the first time.

Rheum palmatum L. and Salvia miltiorrhiza Bge. Alleviates Acute Pancreatitis by Regulating Th17 Cell Differentiation: An Integrated Network Pharmacology Analysis, Molecular Dynamics Simulation and Experimental Validation.

OBJECTIVE: To identify the core targets of Rheum palmatum L. and Salvia miltiorrhiza Bge., (Dahuang-Danshen, DH-DS) and the mechanism underlying its therapeutic efficacy in acute pancreatitis (AP) using a network pharmacology approach and validate the findings in animal experiments. METHODS: Network pharmacology analysis was used to elucidate the mechanisms underlying the therapeutic effects of DH-DS in AP. The reliability of the results was verified by molecular docking simulation and molecular dynamics simulation. Finally, the results of network pharmacology enrichment analysis were verified by immunohistochemistry, Western blot analysis and real-time quantitative PCR, respectively. RESULTS: Sixty-seven common targets of DH-DS in AP were identified and mitogen-activated protein kinase 3 (MAPK3), Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), protein c-Fos (FOS) were identified as core targets in the protein interaction (PPI) network analysis. Gene ontology analysis showed that cellular response to organic substance was the main functions of DH-DS in AP, and Kyoto Encyclopedia of Genes and Genomes analysis showed that the main pathway included Th17 cell differentiation. Molecular docking simulation confirmed that DH-DS binds with strong affinity to MAPK3, STAT3 and FOS. Molecular dynamics simulation revealed that FOS-isotanshinone II and STAT3-dan-shexinkum d had good binding capacity. Animal experiments indicated that compared with the AP model group, DH-DS treatment effectively alleviated AP by inhibiting the expression of interleukin-1ß, interleukin-6 and tumor necrosis factor-α, and blocking the activation of Th17 cell differentiation (P<0.01). CONCLUSION: DH-DS could inhibit the expression of inflammatory factors and protect pancreatic tissues, which would be functioned by regulating Th17 cell differentiation-related mRNA and protein expressions.

Inhibitory effect of Bofutsushosan (Fangfengtongshengsan) extract on the absorption of fructose in rats and mice.

Bofutsushosan (BTS; fangfengtongshengsan in Chinese) is a formula in traditional Japanese Kampo and Chinese medicine comprising 18 crude drugs and used to treat obesity and metabolic syndrome. In our previous study, BTS boiling water extract inhibited the uptake of fructose absorbed via glucose transporter 5 into cultured cells. In this study, the inhibitory effect of BTS extract on the absorption of fructose from the intestine was investigated in vivo. The extract of BTS was orally administered to rats at doses equivalent to 25-fold of the daily dose for humans. One minute after sample administration, fructose was orally administered and blood samples were collected from the jugular vein 0.5, 1, 1.5, 2, and 4 h after the administration of fructose. The absorption of fructose from the intestine was significantly reduced by treatment with BTS extract, and this in vivo study reproduced previous in vitro results. Subsequently, the blood samples were collected from the portal vein 30 min after the oral administration of fructose in mice. BTS extract significantly reduced fructose absorption in mice, and compared the effect of modified BTS samples by removing one to several crude drugs from BTS. We found that the dried rhizome of Rheum palmatum (RR) significantly contributed to the inhibitory effect of BTS on fructose absorption. We found sennoside A to be the active ingredient of RR for the inhibition of fructose absorption, and that its effect almost saturated at a dose of 3 mg/kg. These results support the action mechanisms of BTS when used for the treatment of obesity in clinics and drug stores.

Synergistic Inhibiting Effect of Phytochemicals in Rheum palmatum on Tyrosinase Based on Metabolomics and Isobologram Analyses.

Tyrosinase (TYR) plays a key role in the enzymatic reaction that is responsible for a range of unwanted discoloration effects, such as food browning and skin hyperpigmentation. TYR inhibitors could, therefore, be candidates for skin care products that aim to repair pigmentation problems. In this study, we used a metabolomics approach combined with the isobologram analysis to identify anti-TYR compounds within natural resources, and evaluate their possible synergism with each other. Rheum palmatum was determined to be a model plant for observing the effect, of which seven extracts with diverse phytochemicals were prepared by way of pressurized solvent extraction. Each Rheum palmatum extract (RPE) was profiled using nuclear magnetic resonance spectroscopy and its activity of tyrosinase inhibition was evaluated. According to the orthogonal partial least square analysis used to correlate phytochemicals in RPE with the corresponding activity, the goodness of fit of the model (R2 = 0.838) and its predictive ability (Q2 = 0.711) were high. Gallic acid and catechin were identified as the active compounds most relevant to the anti-TYR effect of RPE. Subsequently, the activity of gallic acid and catechin were evaluated individually, and when combined in various ratios by using isobologram analysis. The results showed that gallic acid and catechin in the molar ratios of 9:5 and 9:1 exhibited a synergistic inhibition on TYR, with a combination index lower than 0.77, suggesting that certain combinations of these compounds may prove effective for use in cosmetic, pharmaceutical, and food industries.

Phylogenomics, phylogeography and germplasms authentication of the Rheum palmatum complex based on complete chloroplast genomes.

As a traditional Chinese medicine, rhubarb is used to treat several diseases such as severe acute pancreatitis, sepsis and chronic renal failure. However, few studies focused on the authentication of germplasm for the Rheum palmatum complex, and no studies have been conducted to elucidate the evolutionary history of the R. palmatum complex using plastome datasets. Hence, we aim to develop the potential molecular markers to identify the elite germplasms of rhubarb and explore the divergence and biogeographic history of the R. palmatum complex based on the newly sequenced chloroplast genome datasets. Chloroplast genomes of thirty-five the R. palmatum complex germplasms were sequenced, and the length ranged from 160,858 to 161,204 bp. The structure, gene content and gene order were highly conserved across all genomes. Eight InDels and sixty-one SNPs loci could be used to authenticate the high-quality germplasms of rhubarb in specific areas. Phylogenetic analysis revealed that all rhubarb germplasms were clustered in the same clade with high bootstrap support values and Bayesian posterior probabilities. According to the molecular dating result, the intraspecific divergence of the complex occurred in the Quaternary, which might be affected by climatic fluctuation. The biogeography reconstruction indicated that the ancestor of the R. palmatum complex might originate from the Himalaya-Hengduan Mountains or/and Bashan-Qinling Mountains, and then spread to surrounding areas. Several useful molecular markers were developed to identify rhubarb germplasms, and our study will provide further understanding on speciation, divergence and biogeography of the R. palmatum complex.

Integrated network pharmacology and DSS-induced colitis model to determine the anti-colitis effect of Rheum palmatum L. and Coptis chinensis Franch in granules.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheum palmatum L. (RP) and Coptis chinensis Franch. (CC), frequently used as herbal pair (HP) in clinical practicing of traditional Chinese medicine, exerted predominate efficacies in colitis treatment. However, the mechanism of their synergism lacks scientific explanation. AIM OF THE STUDY: By integrating network pharmacology and DSS-induced colitis model, the anti-colitis effects and synergistic molecular mechanisms of RP-CC combination was determined. MATERIALS AND METHODS: In vivo study, mice were divided into control, model, RP, CC and RP-CC (low, middle, high) groups, 2.5% DSS was administrated to induce colitis for consecutive 7 days, subsequently, the therapeutic effects were evaluated from body weight changes, disease activity index (DAI), and pathological conditions. After determining the shared and exclusive targets of RP and CC, respectively by network pharmacology, CETSA, WB, and qPCR were utilized to verify the action modes of RP and CC on specific targets. RESULTS: Compared to RP or CC used alone, RP-CC combination can significantly protect colon tissues from inflammatory damage in a dose-dependent manner via remarkably alleviating DAI and colon shortening. Network pharmacological analysis suggested that AKT1 would be the core target for RP-CC synergism since these two herbs could simultaneously but non-competitively bind to AKT1 at different sits. Furthermore, RP and CC could also influencing HIF and MAPK pathways, respectively, these additional actions attribute to more optimizing effectiveness towards colitis. CONCLUSION: In contrast to the mild therapeutic effects of RP or CC individually, RP-CC herb pair could exert strong and synergistic effects in treatment of colitis via non-competitive binding to AKT1 simultaneously, as well as exclusively influencing MAPK and HIF pathways. Our study not only provides the evidence for understanding the combined effect of RP and CC, but also brings up a new strategy and suggestive thoughts for the rationality of HP-based TCM formula.

Rheum officinale and Salvia miltiorrhiza inhibit renal fibrosis via miR-21/PTEN/Akt signaling pathway in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: As one of the main components of many famous Chinese herbal formulas, Rheum palmatum L. and Salvia miltiorhiza Bunge (RS) are extensively used to treat chronic kidney disease (CKD). RS has been proved to improve renal function and relieve renal fibrosis (RF), but the potential mechanism remains a mystery. AIM OF THE STUDY: The purpose of this study is to determine whether microRNA-21 (miR-21) is associated with RF progression, as well as whether RS protects against RF through miR-21/PTEN/AKT signaling. MATERIALS AND METHODS: (1) The rat model of RF was established using unilateral ureteral obstruction (UUO). After UUO surgery, miR-21 levels in plasma were detected by RT-PCR and RF scores were assessed by Masson's trichrome stain at days 3, 7, 14 and 21. The correlation analysis of the above two indexes was carried out by Spearman correlation analysis. (2) Human proximal tubular epithelial cells (HK-2) was transfected with miR-21 mimic and inhibitor, and then the levels of phosphatase and tensin homolog (PTEN) protein and mRNA were measured with Western blotting and RT-PCR, respectively. (3) TGF-ß (10 ng/mL) was added into HK-2 cells to induce fibrosis, followed by the intervention of RS-containing rat serum. PTEN and protein kinase-B (Akt) phosphorylation, as well as the expression of PTEN protein in HK-2 cells, were assessed by RT-PCR, Western blotting and immunofluorescence. (4) The rat models of RF were prepared by UUO and treated with RS. Serum creatinine and urea nitrogen levels were measured. RF score was determined by Masson's trichrome stain. RT-PCR was used to determine the expression of miR-21, PTEN, and Akt mRNA. Western blotting was used to determine the expression of PTEN and Akt proteins. RESULTS: A positive correlation was found between plasma miR-21 levels and RF scores of rats after UUO surgery at Days 3, 7, 14 and 21. It was confirmed that miR-21 targeted PTEN. RS drug-containing serum could rise the expression of PTEN and reduce Akt phosphorylation of HK-2 cells induced by TGF-ß. Moreover, RS drug-containing serum could increase PTEN expression and reduce Akt phosphorylation induced by miR-21 mimic in HK-2 cells. The rats treated with RS had significantly decreased serum creatinine and urea nitrogen levels and a lower RF score. RS also decreased miR-21 and Akt expressions, increased PTEN expression of UUO rats. CONCLUSION: There was a positive correlation between plasma miR-21 levels and RF scores. The inhibitory effect of RS on RF might be mediated by miR-21/PTEN/AKT signaling.

Anti-Psoriatic Effect of Rheum palmatum L. and Its Underlying Molecular Mechanisms.

Psoriasis is a chronic, immune-mediated inflammatory skin disorder. Rheum palmatum L. is a common traditional medicinal herb with anti-inflammatory and immunomodulatory activities. This study aimed to investigate the anti-psoriatic effects of the ethanolic extract from R. palmatum L. (RPE) and its chemical constituents, as well as the mechanisms underlying their therapeutic significance. An imiquimod (IMQ)-induced psoriasis-like mouse model was used to examine the anti-psoriatic effect of RPE in vivo. Network pharmacological analysis was performed to investigate the potential targets and related pathways of the RPE components, including rhein, emodin, chrysophanol, aloe-emodin, and physcion. The anti-inflammatory effects and underlying mechanisms of these components were examined using in vitro models. Topical application of RPE alleviated psoriasis-like symptoms and reduced levels of inflammatory cytokines and proliferation markers in the skin. Network pharmacological analysis revealed that RPE components target 20 genes that are linked to psoriasis-related pathways, such as IL-17, MAPK, and TNF signaling pathways. Among the five components of RPE, rhein and emodin showed inhibitory effects on TNF-α and IL-17 production in EL-4 cells, attenuated the production of CXCL8, CXCL10, CCL20, and MMP9, and reduced proliferation in HaCaT cells. Chrysophanol, aloe-emodin, and physcion were less effective than rhein and emodin in suppressing inflammatory responses and keratinocyte proliferation. The effects of these compounds might occur through the inhibition of the ERK, STAT3, and NF-κB signaling pathways. This study suggested the anti-psoriatic effect of RPE, with rhein and emodin as the main contributors that regulate multiple signaling pathways.

Efficacy of a Persian herbal medicine compound on coronavirus disease 2019 (COVID-19): A randomized clinical trial.

Background: The global attention to the capacities of traditional medicine for alleviating the clinical manifestations of COVID-19 has been growing. The present trial aimed to evaluate the efficacy and safety of a Persian herbal medicine formula among patients with COVID-19. Methods: The present trial was conducted in Afzalipour hospital, Kerman, Iran, from June to September 2020. Hospitalized COVID-19 patients were randomly divided into intervention (Persian herbal medicine formula + routine treatment) or control (only routine treatment) groups. The intervention group received both capsule number 1 and 2 every 8 hours for 7 days. Capsule number 1 contained extract of the Glycyrrhiza glabra, Punica granatum, and Rheum palmatum, and the second capsule was filled by Nigella sativa powder. Participants were followed up to 7 days. The primary outcome was the number of hospitalization days, while cough, fever, and respiratory rate, days on oxygen (O2) therapy, and mortality rate were considered as the secondary outcomes. Results: Eighty-two patients were enrolled to the study, while 79 cases completed the trial and their data were analyzed (mean age: 59.1 ± 17.1 years). Based on the results, the Persian medicine formula decreased the mean hospitalization days, so that the mean difference of length of hospitalization as primary outcome was 2.95 ± 0.43 days. A significant clinical improvement was observed regarding dyspnea, need for O2) therapy, and respiratory rate in the intervention group. No adverse effects were reported. Conclusion: The present study supported the use of the Persian medicine formula as an adjuvant therapy for hospitalized COVID-19 patients. Study registration: Iranian Registry of Clinical Trials (www.irct.ir): IRCT20200330046899N1. Study registration: Iranian Registry of Clinical Trials (www.irct.ir): IRCT20200330046899N1.

Antimicrobial Activity of Eucalyptus globulus, Azadirachta indica, Glycyrrhiza glabra, Rheum palmatum Extracts and Rhein against Porphyromonas gingivalis.

Novel plant-derived antimicrobials are of interest in dentistry, especially in the treatment of periodontitis, since the use of established substances is associated with side effects and concerns of antimicrobial resistance have been raised. Thus, the present study was performed to quantify the antimicrobial efficacy of crude plant extracts against Porphyromonas gingivalis, a pathogen associated with periodontitis. The minimal inhibitory concentrations (MICs) of Eucalyptus globulus leaf, Azadirachta indica leaf, Glycyrrhiza glabra root and Rheum palmatum root extracts were determined by broth microdilution for P. gingivalis ATCC 33277 according to CLSI (Clinical and Laboratory Standards Institute). The MICs for the E. globulus, A. indica and G. glabra extracts ranged from 64 mg/L to 1024 mg/L. The lowest MIC was determined for an ethanolic R. palmatum extract with 4 mg/L. The MIC for the anthraquinone rhein was also measured, as the antimicrobial activity of P. palmatum root extracts can be partially traced back to rhein. Rhein showed a remarkably low MIC of 0.125 mg/L. However, the major compounds of the R. palmatum root extract were not further separated and purified. In conclusion, R. palmatum root extracts should be further studied for the treatment of periodontitis.

Analysis of synonymous codon usage of transcriptome database in Rheum palmatum.

BACKGROUND: Rheum palmatum is an endangered and important medicinal plant in Asian countries, especially in China. However, there is little knowledge about the codon usage bias for R. palmatum CDSs. In this project, codon usage bias was determined based on the R. palmatum 2,626 predicted CDSs from R. palmatum transcriptome. METHODS: In this study, all codon usage bias parameters and nucleotide compositions were calculated by Python script, Codon W, DNA Star, CUSP of EMBOSS. RESULTS: The average GC and GC3 content are 46.57% and 46.6%, respectively, the results suggested that there exists a little more AT than GC in the R. palmatum genes, and the codon bias of R. palmatum genes preferred to end with A/T. We concluded that the codon bias in R. palmatum was affect by nucleotide composition, mutation pressure, natural selection, gene expression levels, and the mutation pressure is the prominent factor. In addition, we figured out 28 optimal codons and most of them ended with A or U. The project here can offer important information for further studies on enhancing the gene expression using codon optimization in heterogeneous expression system, predicting the genetic and evolutionary mechanisms in R. palmatum.

Effects of rhein and Rheum palmatum L. extract on the pharmacokinetics and tissue distribution of aristolochic acid I and its demethylated metabolite in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochic acid nephropathy (AAN) is a kidney disease caused by the administration of plants containing aristolochic acids (AAs). Aristolochic acid I (AAI) is the main toxic component in AAs. Organic anion transporters (OATs) 1 and 3 mediate the renal uptake of AAI, which is related to AAN. In our previous study, we found that anthraquinones derived from the herbal medicine Rheum palmatum L. (RP) inhibited both OAT1 and OAT3, with rhein exhibiting the greatest potency among the components. AIM OF THE STUDY: This study aimed to investigate the effects of rhein and RP extract on the pharmacokinetics and tissue distribution of AAI and its demethylated metabolite (8-hydroxy-aristolochic acid I [AAIa]) in rats. MATERIALS AND METHODS: Rhein and RP extract were used as OAT inhibitors, and AAI was used as the toxic substrate. The pharmacokinetics and tissue distribution of AAI and AAIa in rats following the intravenous injection of AAI (10 mg/kg) in the presence and absence of rhein (100 mg/kg) or RP extract (5 g crude drug/kg) were investigated. RESULTS: Co-administration with rhein increased AUC0-∞ of AAI and AAIa by 39 and 44%, respectively. However, the renal level of AAI was decreased to 50, 42, and 58% of those in rats treated with AAI alone at 5, 10, and 20 min after treatment, respectively, and the renal level of AAIa was decreased to 58, 57, and 61% of the level in rats treated with AAI alone, respectively, at these time points. In the RP extract co-administration group, AAI and AAIa plasma exposure was not significantly increased, but renal accumulation of AAI was decreased to 63, 58, and 68% of that in rats treated with AAI alone at 5, 10, and 20 min after treatment, respectively. In addition, renal accumulation of AAIa was decreased to 74, 70, and 70% of that in rats treated with AAI alone at 5, 10, and 20 min after treatment, respectively. CONCLUSIONS: This study indicated that co-administration with rhein significantly increased the plasma exposure of AAI and AAIa while decreased their renal accumulation in rats. RP extract reduced the renal accumulation of AAI and AAIa, but have no significant effect on their plasma exposure levels in rats.

Exploration of the Potential Mechanisms of Compounds from Rheum palmatum L. against Chronic Obstructive Pulmonary Disease: A Network Pharmacology Study.

BACKGROUND: Rheum palmatum L. (RpL) is a traditional Chinese medicine commonly used clinically. However, there was no systematic research to elucidate the mechanisms of RpL acting on COPD. OBJECTIVE: To explore the potential mechanisms against COPD based on network pharmacology. METHODS: The active compounds of RpL were retrieved from TCMSP database, and their corresponding targets were obtained through TCMSP and STITCH databases. COPD-related targets were identified from the TTD, GeneCards and MalaCards database. Drug-disease genes were obtained through intersection analysis, and the correlation between these genes and COPD was analyzed. After that, a protein-protein interaction network was constructed and enrichment analysis was performed. Then, key targets were obtained according to the network topology attributes analysis. Finally, the Auto dock vina 1.1.2 was used for molecular docking to verify the binding ability between the active compounds and key targets. RESULTS: There were 8 active compounds and 90 corresponding targets were identified in RpL. A total of 4502 COPD-related targets were obtained from databases. After cross-analysis, 81 drug-disease targets were obtained. Drug-disease targets mainly regulated apoptosis and inflammatory responses and participated in related signal pathways. Besides, 28 key genes were obtained from the network topology analysis. TP53, TNF, NFKB1, VEGFA, MMP9, and MMP1 were selected to dock with the compounds. The results of molecular docking showed that the above targets have different affinities with the 8 active compounds of RpL. CONCLUSION: The mechanisms of RpL acting on COPD were mainly related to the regulation of apoptosis, inflammatory response, and airway remodeling.

Hepatoprotective Potency of Chrysophanol 8-O-Glucoside from Rheum palmatum L. against Hepatic Fibrosis via Regulation of the STAT3 Signaling Pathway.

Rhubarb is a well-known herb worldwide and includes approximately 60 species of the Rheum genus. One of the representative plants is Rheum palmatum, which is prescribed as official rhubarb due to its pharmacological potential in the Korean and Chinese pharmacopoeia. In our bioactive screening, we found out that the EtOH extract of R. palmatum inhibited hepatic stellate cell (HSC) activation by transforming growth factor ß1 (TGF-ß1). Chemical investigation of the EtOH extract led to the isolation of chrysophanol 8-O-glucoside, which was determined by structural analysis using NMR spectroscopic techniques and electrospray ionization mass spectrometry (ESIMS). To elucidate the effects of chrysophanol 8-O-glucoside on HSC activation, activated LX-2 cells were treated for 48 h with chrysophanol 8-O-glucoside, and α-SMA and collagen, HSC activation markers, were measured by comparative quantitative real-time PCR (qPCR) and western blotting analysis. Chrysophanol 8-O-glucoside significantly inhibited the protein and mRNA expression of α-SMA and collagen compared with that in TGF-ß1-treated LX-2 cells. Next, the expression of phosphorylated SMAD2 (p-SMAD2) and p-STAT3 was measured and the translocation of p-STAT3 to the nucleus was analyzed by western blotting analysis. The expression of p-SMAD2 and p-STAT3 showed that chrysophanol 8-O-glucoside strongly downregulated STAT3 phosphorylation by inhibiting the nuclear translocation of p-STAT3, which is an important mechanism in HSC activation. Moreover, chrysophanol 8-O-glucoside suppressed the expression of p-p38, not that of p-JNK or p-Erk, which can activate STAT3 phosphorylation and inhibit MMP2 expression, the downstream target of STAT3 signaling. These findings provided experimental evidence concerning the hepatoprotective effects of chrysophanol 8-O-glucoside against liver damage and revealed the molecular basis underlying its anti-fibrotic effects through the blocking of HSC activation.

A Network Pharmacology Approach to Investigate the Anticancer Mechanism and Potential Active Ingredients of Rheum palmatum L. Against Lung Cancer via Induction of Apoptosis.

Rheum palmatum L. (RPL) is a known traditional herbal medicine with the functions of "heat-clearing and damp-drying" in traditional Chinese medicine. Its anti-cancer effect against lung cancer has been confirmed previously, but the related mechanisms and active substances for its action has been little studied. This study adopted the network pharmacology, built the network map of drug ingredients and disease targets (DDN), and discussed the effective components of RPL and its possible mechanisms. All constituents of RPL were collected through database search and literature mining, and the potential active constituents were screened. The inverse pharmacophore matching model was used to predict the targets of active ingredients, and the method was supplemented by database retrieval and literature mining. Compounds-target data were inputted into Cytoscape software to build the DDN of RPL, and functional annotation analysis and pathway enrichment analysis were carried out. Finally, 20 active compounds were screened, which acted on 817 targets. A total of 22,418 lung cancer-related targets were collected, and 761 overlapped with drug targets. By bioinformatics annotation of these overlapping genes, a total of 235 gene ontology (GO) functional annotation analyses and 46 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were obtained. It was found that the enrichment of GO and KEGG was associated with apoptosis, suggesting RPL plays an anti-lung cancer role via inducing cell apoptosis. Subsequent cell experiment results showed RPL and its active constituents inhibited the proliferation of A549 cells and reduced clone formation rate of A549 cells via induction of apoptosis. In this study, the pharmacodynamic basis and mechanism of RPL against lung cancer were studied from the perspective of systematic pharmacology, which would be beneficial for further elucidating the anticancer effect of RPL on lung cancer.

Solid phase adsorption of anthraquinones from plant extracts by lamellar solids.

Solid phase extraction is nowadays a well validated and powerful technique applicable to complex matrices like plant extracts and phytocomplexes. This process provides concentration and/or purification of selected secondary metabolites from these matrices for subsequent analysis and isolation. In this research article sixteen lamellar solids, comprising layered structures (hydrotalcites, zirconium phosphates, magnesium hydroxide), magnesium oxide, and the phyllosilicates talc and bentonite were investigated for their capacity and performance to selectively adsorb five naturally occurring and widespread anthraquinones (aloe, aloe-emodin, rhein, chrysophanol, and physcion) contained in three ethanolic extracts of well known plants with purgative effects (frangula, senna, and rhubarb). Ethanolic solutions of extracts from these species were vigorously magnetically stirred with fixed quantities of each solid support at room temperature for 1 h. Subsequent HPLC analysis, coupled to photodiode array detection, revealed that, among the solids tested, the hydrotalcite zinc aluminum oleate and magnesium aluminum azelate and magnesium oxide were largely the most effective to this concern allowing to recover anthraquinones (all or some) in good to excellent percentages. Another interesting result was the selective and total removal of rhein by some sorbents from senna and rhubarb extracts. Sorbents were also recyclable and could be re-used to accomplish additional steps without appreciable loss of adsorption capacity. The application of the title solid inorganic and mixed inorganic/organic supports for the selective adsorption and concentration in the solid phase of anthraquinones from commonly used laxative plant species is reported herein for the first time.

Protic Ionic Liquids as Efficient Solvents in Microwave-Assisted Extraction of Rhein and Emodin from Rheum palmatum L.

Rheum palmatum L. (R. palmatum L.) is a traditional Chinese herb and food, in which rhein and emodin are the main bioactive components. The extraction of the two compounds from R. palmatum L. is, thus, of great importance. In this work, protic ionic liquids (PILs) were applied in the microwave-assisted extraction (MAE) of rhein and emodin from R. palmatum L., which avoids the toxicity of organic solvents. The results of the present study indicate that PILs possessing higher polarity exhibit higher extraction ability due to their stronger absorption ability for microwave irradiation. Compared with conventional solvents, such as methanol, trichloromethane, and deep eutectic solvents (DESs), the PIL, 1-butyl-3-himidazolium methanesulfonate ([BHim]MeSO3) reported herein is more efficient. The selected extraction conditions of liquid-solid ratio, microwave irradiation time, microwave irradiation power, and PIL concentration were 40 g·g-1, 50 s, 280 W, and 80%, respectively. Under the selected conditions, the extraction yields of rhein and emodin were 7.8 and 4.0 mg·g-1, respectively. These results suggest that PILs are efficient extraction solvents for the separation of active components from natural products.

The polyherbal composition Gyeongshingangjeehwan 18 attenuates glucose intolerance and pancreatic steatosis in C57BL/6J mice on a high-fat diet.

Ethnopharmacologic relevance: Gyeongshingangjeehwan 18 (GGEx18) is a polyherbal composition derived from Ephedra sinica Stapf (Ephedraceae), Laminaria japonica Aresch (Laminariaceae), and Rheum palmatum L. (Polygonaceae) that is used as an antiobesity drug in Korean clinics. Its constituents are traditionally known to combat obesity, dyslipidemia, and insulin resistance. OBJECTIVE: This study was undertaken to investigate the effects of GGEx18 on glucose metabolism and pancreatic steatosis in obese C57BL/6 J mice fed a high-fat diet (HFD) and to examine the related cellular and molecular mechanisms. MATERIALS AND METHODS: The mice were grouped and fed for 13 weeks as follows: 1) low-fat diet, 2) HFD, or 3) HFD supplemented with GGEx18 (500 mg/kg/day). Various factors affecting insulin sensitivity and pancreatic function were then assessed via blood analysis, histology, immunohistochemistry, and real-time polymerase chain reaction. RESULTS: GGEx18 treatment of obese mice reduced body weight, total fat, and visceral fat mass. GGEx18 inhibited hyperglycemia and hyperinsulinemia and improved glucose and insulin tolerance. GGEx18 also decreased serum leptin levels and concomitantly increased adiponectin levels. Furthermore, GGEx18-treated mice exhibited reduced pancreatic fat accumulation and normalized insulin-secreting ß-cell area. GGEx18 increased pancreatic expression of genes promoting fatty acid ß-oxidation (i.e., MCAD and VLCAD), whereas expression levels of lipogenesis-related genes (i.e., PPARγ, SREBP-1c, and FAS) declined. DISCUSSION AND CONCLUSION: GGEx18 curtailed impaired glucose metabolism and pancreatic steatosis in our mouse model by regulating pancreatic genes that govern lipid metabolism and improving insulin sensitivity. This composition may benefit patients with impaired glucose tolerance, insulin resistance, and pancreatic dysfunction.