Rhein, which is one of the main active components of Rheum palmatum, has a range of pharmacological activities such as the regulation of the metabolism of glucose and lipids, anti-inflammatory, anti-tumor, anti-fibrosis, etc. Epigenetics refers to the heritable variation of gene expression without altering the DNA sequence. It is involved in the emergence and development of inflammation, renal fibrosis, diabetes, cancer, atherosclerosis, and other diseases, thus becoming a new strategy for the treatment of many di-seases. A series of studies have shown that epigenetic modification may be a common molecular mechanism of various pharmacological effects of rhein. This paper summarized the effects of rhein on the regulation of epigenetic modification and its underlying mechanisms, which involve the regulation of DNA methylation, protein acetylation, and RNA methylation, so as to provide a basis for the development and application of rhein.
Humans ; Anthraquinones/pharmacology* ; DNA Methylation ; Epigenesis, Genetic ; Neoplasms/drug therapy* ; Fibrosis

OBJECTIVE: To investigate the effect of emodin on high glucose (HG)-induced podocyte apoptosis and whether the potential anti-apoptotic mechanism of emodin is related to induction of adenosine-monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)-mediated autophagy in podocytes (MPC5 cells) in vitro. METHODS: MPC5 cells were treated with different concentrations of HG (2.5, 5, 10, 20, 40, 80 and 160 mmol/L), emodin (2, 4, 8 µ mol/L), or HG (40 mmol/L) and emodin (4 µ mol/L) with or without rapamycin (Rap, 100 nmol/L) and compound C (10 µ mol/L). The viability and apoptosis of MPC5 cells were detected using cell counting kit-8 (CCK-8) assay and flow cytometry analysis, respectively. The expression levels of cleaved caspase-3, autophagy marker light chain 3 (LC3) I/II, and AMPK/mTOR signaling pathway-related proteins were determined by Western blot. The changes of morphology and RFP-LC3 fluorescence were observed under microscopy. RESULTS: HG at 20, 40, 80 and 160 mmol/L dose-dependently induced cell apoptosis in MPC5 cells, whereas emodin (4 µ mol/L) significantly ameliorated HG-induced cell apoptosis and caspase-3 cleavage (P<0.01). Emodin (4 µ mol/L) significantly increased LC3-II protein expression levels and induced RFP-LC3-containing punctate structures in MPC5 cells (P<0.01). Furthermore, the protective effects of emodin were mimicked by rapamycin (100 nmol/L). Moreover, emodin increased the phosphorylation of AMPK and suppressed the phosphorylation of mTOR. The AMPK inhibitor compound C (10 µ mol/L) reversed emodin-induced autophagy activation. CONCLUSION Emodin ameliorated HG-induced apoptosis of MPC5 cells in vitro that involved induction of autophagy through the AMPK/mTOR signaling pathway, which might provide a potential therapeutic option for diabetic nephropathy.
Emodin/pharmacology* ; AMP-Activated Protein Kinases/metabolism* ; Podocytes ; Caspase 3/metabolism* ; TOR Serine-Threonine Kinases/metabolism* ; Signal Transduction ; Apoptosis ; Sirolimus/pharmacology* ; Glucose/metabolism* ; Autophagy

Diabetic kidney disease (DKD) is the primary cause of mortality among diabetic patients. With the increasing prevalence of diabetes, it has become a major concern around the world. The therapeutic effect of clinical use of drugs is far from expected, and therapy choices to slow the progression of DKD remain restricted. Therefore, research on new drugs and treatments for DKD has been a hot topic in the medical field. It has been found that rhein has the potential to target the pathogenesis of DKD and has a wide range of pharmacological effects on DKD, such as anti-nephritis, decreasing blood glucose, controlling blood lipids and renal protection. In recent years, the medical value of rhein in the treatment of diabetes, DKD and renal disease has gradually attracted worldwide attention, especially its potential in the treatment of DKD. Currently, DKD can only be treated with medications from a single symptom and are accompanied by adverse effects, while rhein improves DKD with a multi-pathway and multi-target approach. Therefore, this paper reviews the therapeutic effects of rhein on DKD, and proposes solutions to the limitations of rhein itself, in order to provide valuable references for the clinical application of rhein in DKD and the development of new drugs.
Humans ; Diabetic Nephropathies/drug therapy* ; Kidney/pathology* ; Anthraquinones/therapeutic use* ; Diabetes Mellitus

To explore the changes and the reaction mechanisms between soil microecological environment and the content of secon-dary metabolites of plants under water deficit, this study carried out a pot experiment on the 3-leaf stage seedlings of Rheum officinale to analyze their response mechanism under different drought gradients(normal water supply, mild, moderate, and severe drought). The results indicated that the content of flavonoids, phenols, terpenoids, and alkaloids in the root of R. officinale varied greatly under drought stresses. Under mild drought stress, the content of substances mentioned above was comparatively high, and the content of rutin, emodin, gallic acid, and(+)-catechin hydrate in the root significantly increased. The content of rutin, emodin, and gallic acid under severe drought stress was significantly lower than that under normal water supply. The number of species, Shannon diversity index, richness index, and Simpson index of bacteria in the rhizosphere soil were significantly higher than those in blank soil, and the number of microbial species and richness index decreased significantly with the aggravation of drought stresses. In the context of water deficit, Cyanophyta, Firmicutes, Actinobacteria, Chloroflexi, Gemmatimonadetes, Streptomyces, and Actinomyces were the dominant bacteria in the rhizosphere of R. officinale. The relative content of rutin and emodin in the root of R. officinale was positively correlated with the relative abundance of Cyanophyta and Firmicutes, and the relative content of(+)-catechin hydrate and(-)-epicatechin gallate was positively correlated with the relative abundance of Bacteroidetes and Firmicutes. In conclusion, appropriate drought stress can increase the content of secondary metabolites of R. officinale from physiological induction and the increase in the association with beneficial microbe.
Rhizosphere ; Rheum ; Droughts ; Soil ; Catechin ; Emodin ; Bacteria/metabolism* ; Water/metabolism* ; Firmicutes ; Soil Microbiology

OBJECTIVE: To investigate the spectrum-effect relationship between the total anthraquinone extract of Cassia seeds and fluorouracil (5-Fu)-induced liver injury in mice and identify the effective components in the extract. METHODS: A mouse model of liver injury was established by intraperitoneal injection of 5-Fu, with bifendate as the positive control. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and myeloperoxidase (MPO), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in the liver tissue were detected to investigate the effect of the total anthraquinone extract of Cassia seeds (0.4, 0.8 and 1.6 g/kg) on liver injury induced by 5-Fu. HPLC fingerprints of 10 batches of the total anthraquinone extracts were established to analyze the spectrum- effectiveness of the extract against 5- Fu- induced liver injury in mice and screen the effective components using the grey correlation method. RESULTS: The 5- Fu- treated mice showed significant differences in liver function parameters from the normal control mice (P < 0.05), suggesting successful modelling. Compared with those in the model group, serum ALT and AST activities were decreased, SOD and T- AOC activities significantly increased, and MPO level was significantly lowered in the mice treated with the total anthraquinone extract (all P < 0.05). HPLC fingerprints of the 31 components in the total anthraquinone extract of Cassia seeds showed good correlations with the potency index of 5-Fu-induced liver injury but with varying correlation strengths. The top 15 components with known correlations included aurantio-obtusina (peak 6), rhein (peak 11), emodin (peak 22), chrysophanol (peak 29) and physcion (peak 30). CONCLUSION The effective components in the total anthraquinone extract of Cassia seeds, including aurantio-obtusina, rhein, emodin, chrysophanol, and physcion, are coordinated to produce protective effects against 5-Fu-induced liver injury in mice.
Animals ; Mice ; Emodin ; Cassia ; Chemical and Drug Induced Liver Injury, Chronic ; Anthraquinones ; Antioxidants ; Fluorouracil/adverse effects* ; Plant Extracts/pharmacology*

Emodin nanostructured lipid carriers(ED-NLC) were prepared and their quality was evaluated in vitro. Based on the results of single-factor experiments, the ED-NLC formulation was optimized by Box-Behnken response surface method with the dosages of emodin, isopropyl myristate and poloxamer 188 as factors and the nanoparticle size, encapsulation efficiency and drug loading as evaluation indexes. Then the evaluation was performed on the morphology, size and in vitro release of the nanoparticles prepared by emulsification-ultrasonic dispersion method in line with the optimal formulation, i.e., 3.27 mg emodin, 148.68 mg isopropyl myristate and 173.48 mg poloxamer 188. Under a transmission electron microscope(TEM), ED-NLC were spherical and their particle size distribution was uniform. The particle size of ED-NLC was(97.02±1.55) nm, the polymer dispersion index 0.21±0.01, the zeta potential(-38.96±0.65) mV, the encapsulation efficiency 90.41%±0.56% and the drug loading 1.55%±0.01%. The results of differential scanning calorimeter(DSC) indicated that emodin may be encapsulated into the nanostructured lipid carriers in molecular or amorphous form. In vitro drug release had obvious characteristics of slow release, which accorded with the first-order drug release equation. The fitting model of Box-Behnken response surface methodology was proved accurate and reliable. The optimal formulation-based ED-NLC featured concentrated particle size distribution and high encapsulation efficiency, which laid a foundation for the follow-up study of ED-NLC in vivo.
Drug Carriers ; Emodin ; Follow-Up Studies ; Lipids ; Nanostructures

The present study investigated the effect of emodin on the serum metabolite profiles in the chronic constriction injury(CCI) model by non-target metabolomics and explored its analgesic mechanism. Twenty-four Sprague Dawley(SD) rats were randomly divided into a sham group(S), a CCI group(C), and an emodin group(E). The rats in the emodin group were taken emodin via gavage once a day for fifteen days(50 mg·kg~(-1)) on the first day after the CCI surgery. Mechanical withdrawal threshold(MWT) and thermal withdrawal threshold(TWL) in each group were performed before the CCI surgery and 3,7, 11, and 15 days after surgery. After 15 days, blood samples were collected from the abdominal aorta. The differential metabolites were screened out by non-target metabolomics and analyzed with Kyoto Encyclopedia of Genes and Genomes(KEGG) and ingenuity pathway analysis(IPA). From the third day after CCI surgery, the MWT and TWL values were reduced significantly in both CCI group and emodin group, compared with the sham group(P<0.01). At 15 days post-surgery, the MWT and TWL values in emodin group increased significantly compared with the CCI group(P<0.05). As revealed by non-target metabolomics, 72 differential serum metabolites were screened out from the C-S comparison, including 41 up-regulated and 31 down-regulated ones, while 26 differential serum metabolites from E-C comparison, including 10 up-regulated and 16 down-regulated ones. KEGG analysis showed that the differential metabolites in E-C comparison were enriched in the signaling pathways, such as sphingolipid metabolism, arginine biosynthesis, glycerophospholipid metabolism, and tryptophan metabolism. IPA showed that the differential metabolites were mainly involved in the lipid metabolism-molecular transport-small molecule biochemistry network. In conclusion, emodin can exert an analgesic role via regulating sphingolipid metabolism and arginine biosynthesis.
Analgesics/pharmacology* ; Animals ; Arginine ; Emodin/pharmacology* ; Neuralgia/metabolism* ; Rats ; Rats, Sprague-Dawley ; Sphingolipids

This study aimed to explore the efficacy and mechanism of combined rhein and emodin in the treatment of ulcerative colitis(UC) from the aspects of network pharmacology, animal inflammation improvement and molecular mechanism. Network pharmacology predicted that combined rhein and emodin acted on 52 potential targets, mainly participating in signaling pathways such as cancer, PI3 K/AKT, microRNAs in cancer and apoptosis. PI3 K/AKT signaling pathway has been reported to be closely related to UC, and the optimal candidate pathway for combined therapy. The UC mice model was established by dextran sodium sulfate, and then the modeled mice were randomly divided into control group, model group, rhein group, emodin group, rhein+emodin group and sulfasalazine group. After administration, compared with the conditions in model group, body weight, disease activity index(DAI) score, colon length, TNF-α, IL-6, IL-1β and myeloperoxidase(MPO) of mice in rhein+emodin group were improved(P<0.01); colonic mucosal injury was significantly reduced; the expression of p-PI3 K/PI3 K and p-AKT/AKT proteins were down-regulated(P<0.01). All the above indices were better than those in the rhein/emodin group alone. The Jin's Q-values of the effect of combined rhein and emodin on colon length, TNF-α, IL-6, IL-1β, MPO, p-PI3 K/PI3 K and p-AKT/AKT were all greater than 1.15, which indicated that there was obvious synergistic effect between rhein and emodin. In all, rhein and emodin have synergistic effect in the treatment of UC, and the mechanism may be related to the inhibition of PI3 K/AKT signaling pathway and the down-regulation of proinflammatory factors. They are the new components in the treatment of UC, which is worthy of attention.
Animals ; Anthraquinones ; Colitis, Ulcerative/metabolism* ; Colon ; Disease Models, Animal ; Emodin/pharmacology* ; Interleukin-6/metabolism* ; Mice ; Proto-Oncogene Proteins c-akt/metabolism* ; Rheum ; Tumor Necrosis Factor-alpha/metabolism*

This study aims to establish an ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) method for the determination of emodin-8-O-β-D-glucoside(EG) and its metabolites in plasma, and to investigate the toxicokinetics(TK) behavior of them in rats. To be specific, the TK of EG and its metabolites from the first to the last administration in the repeated dose toxicity study was determined, and the kinetic parameters were calculated. The exposure of EG prototype and metabolites in rat plasma after oral administration of different doses of EG was evaluated. The result showed that the prototype of EG and its metabolites aloe-emodin-8-O-β-D-glucoside, emodin, aloe-emodin, and hydroxyemodin could be detected in rats after oral administration of high-, medium-, and low-dose EG. The area under the curve(AUC) of the prototype and metabolites after the first and last administration was in positive correlation with the dose. The time to the maximum concentration(T_(max)) of EG and metabolites in the three administration groups was <6 h, and the longest in vivo residence time was 12 h. The T_(max) and in vivo residence time of EG were prolonged with the increase in the dose. The metabolites emodin, aloe-emodin, and hydroxyemodin all had two peaks. Both hydroxyemodin and aloe-emodin exhibited increased plasma exposure, slow metabolism, and accumulation in vivo. In addition, aloe-emodin-8-O-β-D-glucoside and emodin disappeared with the increase in dose, suggesting the change of the metabolic pathway of EG in vivo in the case of high-dose administration. The mechanism of high-dose EG in vivo needs to be further explored. This study preliminarily elucidates the TK behavior of EG in rats, which is expected to support clinical drug use.
Animals ; Anthraquinones ; Chromatography, High Pressure Liquid/methods* ; Emodin/toxicity* ; Glucosides/toxicity* ; Mass Spectrometry ; Rats ; Toxicokinetics

The present study aimed to explore the material basis of Rhei Radix et Rhizoma-Coptidis Rhizoma combination in alleviating "bitter-cold" properties based on the supramolecular chemistry of Chinese medicine.Dynamic light scattering and scanning/transmission electron microscopy were used to characterize the morphological characteristics of supramolecules in the decoction of Rhei Radix et Rhizoma and Coptidis Rhizoma.The chemical composition of supramolecules, as well as the dissolution and release processes of supramolecules and the medicinal components of Coptidis Rhizoma decoction, was determined by the high-performance liquid chromatography-mass spectrometry.The differences in "bitter-cold" medicinal properties between Rhei Radix et Rhizoma decoction, Coptidis Rhizoma decoction, and co-decoction were analyzed by sensory evaluation, electronic tongue, mouse diarrhea model, and pathological indicators.The anthraquinones/tannins and alkaloids interacted to form supramolecules with a scale of about 400 nm when Rhei Radix et Rhizoma and Coptidis Rhizoma were decocted together, which delayed the dissolution and release of the active components represented by berberine. Compared with the consequence of single drug administration at 4 g·kg~(-1), the combination of the two drugs at 8 g·kg~(-1) significantly alleviated the "bitter-cold" properties.The effective components interacted to form supramolecules in the co-decoction of Rhei Radix et Rhizoma and Coptidis Rhizoma, which affected the dissolution and release of the effective components of Chinese medicinal decoction, thereby alleviating the "bitter-cold" properties.The findings of this study provide a new idea for revealing the scientific compatibility of Rhei Radix et Rhizoma and Coptidis Rhizoma.
Mice ; Animals ; Drugs, Chinese Herbal/chemistry* ; Medicine, Chinese Traditional ; Rhizome/chemistry* ; Anthraquinones/analysis* ; Chromatography, High Pressure Liquid/methods* ; Antineoplastic Agents