The Protective Effect of Radix Polygoni Multiflori on Diabetic Encephalopathy via Regulating Myosin Light Chain Kinase Expression

Prepared Radix Polygoni Multiflori and emodin alleviate lipid droplet accumulation in nonalcoholic fatty liver disease through MAPK signaling pathway inhibition

As one of the most common liver diseases, nonalcoholic fatty liver disease (NAFLD) affects almost one-quarter of the world's population. Although the prevalence of NAFLD is continuously rising, effective medical treatments are still inadequate. Radix Polygoni Multiflori (RPM) is a traditional Chinese herbal medicine. As a processed product of RPM, prepared Radix Polygoni Multiflori (PRPM) has been reported to have antioxidant and anti-inflammatory effects. This study investigated whether PRPM treatment could significantly improve NAFLD. We used recent literature, the Herb database and the SwissADME database to isolate the active compounds of PRPM. The OMIM, DisGeNET and GeneCards databases were used to isolate NAFLD-related target genes, and GO functional enrichment and KEGG pathway enrichment analyses were conducted. Moreover, PRPM treatment in NAFLD model mice was evaluated. The results indicate that the target genes are mainly enriched in the AMPK and de novo lipogenesis signaling pathways and that PRPM treatment improves NAFLD disease in model mice. Here, we found the potential benefits of PRPM against NAFLD and demonstrated in vivo and in vitro that PRPM and its ingredient emodin downregulate phosphorylated P38/P38, phosphorylated ERK1/2 and genes related to de novo adipogenesis signaling pathways and reduce lipid droplet accumulation. In conclusion, our findings revealed a novel therapeutic role for PRPM in the treatment of NAFLD and metabolic inflammation.

Pharmacokinetic characteristics of emodin in polygoni Multiflori Radix Praeparata

ETHNOPHARMACOLOGICAL RELEVANCE

Polygoni Multiflori Radix Praeparata (Zhiheshouwu) has been a Wudang Taoist medicine for tonifying the liver and kidney, resolving turbidity and reducing lipid. Emodin is one of the active anthraquinones in Zhiheshouwu. Our previous studies showed that emodin (EM) and the other anthraquinones in Zhiheshouwu extract (HSWE) exerted similar inhibitory effects on liver cancer cells in vitro. However, it is still unknown if the other anthraquinones enhance pharmacokinetics (PK) of EM in HSWE in vivo.

AIM OF THE STUDY

In this study, we compared the PK characteristics of EM alone with that in Zhiheshouwu aiming to explore which anthraquinones in HSWE contribute to the changed PK of EM in rats.

MATERIALS AND METHODS

Quality control of HSWE was determined using high performance liquid chromatography (HPLC). The ratios of emodin to other anthraquinones, physcion (PH), chrysophanol (CH), rhein (RH), aloe-emodin (AE), emodin-8-O-β-D-glycoside (EMG), physcion-1-O-β-D-glycoside (PHG) and chrysophanol-8-O-β-D-glycoside (CHG) in HSWE were determined and analyzed using UPLC combined with tandem mass spectrometry (UPLC/MS). The PK parameters and intestinal tissue concentration of EM alone, EM in HSWE, or with other anthraquinones in SD rats were analyzed using UPLC/MS.

RESULTS

The quality of the Zhiheshouwu samples met the quality standard of the Chinese Pharmacopoeia (Version 2020). The PK results showed that compared with EM alone, C_max (239.90 ± 146.71 vs. 898.46 ± 291.62, P < 0.001), T_max (0.26 ± 0.15 vs. 12.55 ± 1.33, P < 0.001), AUC_0-t (1575.09 ± 570.46 vs. 12154.96 ± 5394.25, P < 0.001), and AUC_0-∞ (4742.51 ± 1837.62 vs. 37131.34 ± 21647.39, P < 0.001) of EM in HSWE were decreased due to PH and EMG, while the values of V_d (380.75 ± 217.74 vs. 11.75 ± 7.35, P < 0.001), T_1/2 (10.81 ± 1.99 vs. 6.65 ± 2.76, P < 0.05) and CL (19.30 ± 7.82 vs. 2.78 ± 1.88, P < 0.001) of EM in HSWE were increased due to PH and AE. In addition, the intestinal tissue concentration of emodin in HSWE was decreased compared with that of EM alone in 20 and 780 min (25.37 ± 5.98 vs. 43.29 ± 4.16 and 26.72 ± 4.03 vs. 43.40 ± 14.19, respectively. P < 0.05) dominantly due to RH and PH.

CONCLUSION

In conclusion, compared with treatment of EM alone, the AUC_0-t value of EM in HSWE was decreased with different ways in rats. PH shortened T_max, and increased V_d and CL. While AE prolonged T_1/2 of EM. This indicated that the other anthraquinones in HSWE changed the PK of EM in rats and participated in the complex effects of EM on liver cancer. Besides the other anthraquinones, other components (e.g., 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside) in Zhiheshouwu may contribute in the pharmacokinetic and pharmacodynamic interactions with EM for anti-liver cancer.

Molecular identification and functional characterization of two glycosyltransferases genes from Fallopia multiflora

The traditional Chinese medicine plant Fallopia multiflora (Thunb.) Harald. contains various pharmacodynamically active glycosides, such as stilbene glycosides, anthraquinone (AQ) glycosides, and flavonoid glycosides. Glycosylation is an important reaction in plant metabolism that is generally completed by glycosyltransferase in the last step of the secondary metabolite biosynthesis pathway, and it can improve the beneficial properties of many natural products. In this study, based on the transcriptome data of F. multiflora, we cloned two Uridine-diphosphate-dependent glycosyltransferases (UGTs) from the cDNA of F. multiflora (FmUGT1 and FmUGT2). Their full-length sequences were 1602 and 1449 bp, encoding 533 and 482 amino acids, respectively. In vitro enzymatic reaction results showed that FmUGT1 and FmUGT2 were promiscuous and could catalyze the glycosylation of 12 compounds, including stilbenes, anthraquinones, flavonoids, phloretin, and curcumin, and we also obtained and structurally identified 13 glycosylated products from both of them. Further experiments on the in vivo function of FmUGT1 and FmUGT2 showed that 2, 3, 5, 4'- tetrahydroxy stilbene-2-O-β-d-glucoside (THSG) content in hairy roots was elevated significantly when FmUGT1 and FmUGT2 were overexpressed and decreased accordingly in the RNA interference (RNAi) groups. These results indicate that FmUGT1 and FmUGT2 were able to glycosylate a total of 12 structurally diverse types of acceptors and to generate O-glycosides. In addition, FmUGT1 and FmUGT2 efficiently catalyzed the biosynthesis of THSG, and promoted the production of AQs in transgenic hairy roots.

Green tea protects against hippocampal neuronal apoptosis in diabetic encephalopathy by inhibiting JNK/MLCK signaling

Although diabetic encephalopathy (DE) is a major late complication of diabetes, the pathophysiology of postural instability in DE remains poorly understood. Prior studies have suggested that neuronal apoptosis is closely associated with cognitive function, but the mechanism remains to be elucidated. Green tea, which is a non-fermented tea, contains a number of tea polyphenols, alkaloids, amino acids, polysaccharides and other components. Some studies have found that drinking green tea can reduce the incidence of neurodegenerative diseases and improve cognitive dysfunction. We previously found that myosin light chain kinase (MLCK) regulates apoptosis in high glucose-induced hippocampal neurons. In neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, activation of the JNK signaling pathway promotes neuronal apoptosis. However, the relationship between JNK and MLCK remains to be elucidated. Green tea serum was obtained using seropharmacological methods and applied to hippocampal neurons. In addition, a type 1 diabetes rat model was established and green tea extract was administered, and the Morris water maze test, Cell Counting Kit-8 assays, flow cytometry, western blotting and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling assays were used to examine the effects of green tea on hippocampal neuronal apoptosis in diabetic rats. The results demonstrated that green tea can protect against hippocampal neuronal apoptosis by inhibiting the JNK/MLCK pathway and ultimately improves cognitive function in diabetic rats. The present study provided novel insights into the neuroprotective effects of green tea.

2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside, a major bioactive component from Polygoni multiflori Radix (Heshouwu) suppresses DSS induced acute colitis in BALb/c mice by modulating gut microbiota

BACKGROUND

Inflammatory bowel disease (IBD) includes ulcerative colitis (UC) and Crohn's disease (CD), which is a common idiopathic digestive disease without a specific cure or treatment for improvement. Because Polygoni multiflori Radix has a traditional medicinal use to treat intestinal diseases, and the water extract of this herbal medicine had a positive influence on dextran sulfate sodium (DSS) induced UC model in our study. Meanwhile 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) as the major component of the water extract of Polygoni multiflori Radix with yield of more than 10% exhibited the remarkable anti-inflammatory activity in vivo and in vitro, we predicted that TSG may contribute to benefit intestinal tract presented by the water extract of Polygoni multiflori Radix. Therefore, the present study aims to explore the pharmacological effect of this compound on UC model and its possible mechanism to regulate intestinal function through gut microbiota.

METHODS

Ulcerative colitis model was established in BALb/c mice by continuously administrating 3% (w/v) DSS aqueous solution for one week. The disease activity index (DAI), colon length, histopathological examination by H&E and the levels of tight junction proteins (TJP) by immunofluorescence staining were performed in ulcerative colitis model following the protocol. Furthermore, the levels of main inflammatory factors like TNF-α, IL-β, IL-6, and IL-10 were analyzed by the ELIZA kits for the further confirmation of anti-inflammatory activity of TSG on ulcerative colitis model. Finally, 16S rDNA sequencing technology was conducted to explore the composition and relative abundance of gut microbiota of different treatment groups.

RESULTS

TSG treatments effectively increased body weight about 5% of those in DSS group (p < 0.001) as well remarkably reduced the DAI scores to the 50% of those in DSS group (p < 0.001) in the UC model. TSG treatments of either 25 mg/kg (TSG-25) or 100 mg/kg (TSG-100) dosage restored epithelial barrier structure and exhibited obviously intact colon histology with reduced signs of inflammatory cells infiltration, preserved epithelia barrier, restored crypt structure, and increased numbers of goblet cells. TSG treatments could markedly lessen the histopathologic score two or three times than those in DSS group (p < 0.001). Especially for TSG-100 treatment, the fluorescence intensity of ZO-1 and Occludin were nearly back to 80% of those in normal group, and were 1.5 times more than those in the DSS group (p < 0.001). Additionally, direct evidence pointed to TSG as a therapeutically active molecule in the prevention and treatment of UC by significantly reducing the production of these pro-inflammatory cytokines like TNF-α, IL-1β, and IL-6 (p < 0.05-0.001) and increasing the levels of anti-inflammatory cytokine IL-10 (p < 0.05-0.001). Finally, it was found TSG treatments significantly raised the relative abundances of Firmicutes and Bacteroidetes with a dose-dependently and improved the homeostasis of the gut microbiota composition which disrupted by DSS through increasing genus level Lachnospiraceae_NK4A136 and decreasing genus level of Helicobacter, Bacteroides, Parabacteroides.

CONCLUSION

The present results suggested that TSG treatments had a desirable pharmacological effect on acute colitis induced by DSS in the mice as well showed the possible mechanism relate to improve the intestinal function through balancing the gut microbiota of intestinal flora.

Protective Effect of Processed Polygoni multiflori Radix and Its Major Substance during Scopolamine-Induced Cognitive Dysfunction

Alzheimer’s disease (AD) is the most common cognitive disorder in the elderly population. However, effective pharmacological agents targeting AD have not been developed. The processed Polygoni multiflori Radix (PPM) and its main active substance, 2,3,5,4′-tetrahydroxystilbene-2-O-β-glucoside (TSG), has received considerable attention, majorly due to its neuroprotective activities against multiple biological activities within the human body. In this study, we provide new evidence on the therapeutic effect of PPM and TSG during cognitive impairment by evaluating the ameliorative potential of PPM and TSG in scopolamine-induced amnesia in ICR mice. PPM (100 or 200 mg/kg) was orally administered during the experimental period (days 1–15), and scopolamine was intraperitoneally injected to induce cognitive deficits during the behavioural test periods (days 8–15). The administration of PPM and TSG significantly improved memory loss and cognitive dysfunction in behavioural tests and regulated the cholinergic function, brain-derived neurotrophic factor, and neural apoptosis. The present study suggests that PPM and TSG improved scopolamine-induced cognitive dysfunction, but further study has to be supported for the clinical application of PPM and TSG for AD prevention and treatment.

Water extract from processed Polygonum multiflorum modulate gut microbiota and glucose metabolism on insulin resistant rats

Background

The incidence of insulin resistance (IR) has rapidly increased worldwide over the last 20 years, no perfect solution has yet been identified. Finding new therapeutic drugs will help improve this situation. As a traditional Chinese medicine, PPM (processed Polygonum multiflorum) has widely been used in the clinic. Recently, other clinical functions of PPM have been widely analyzed.

Results

Administration of the water extract from PPM decreased the level of FBG, TC, and TG, and increased the level of FGC, thereby reducing the IR index and improving IR. Furthermore, Western blot analysis revealed that PPM significantly increased GPR43 and AMPK expression when compared with the MOD group, and GPR43, AMPK were known as glucose metabolism-related proteins. In addition, treatment with PPM can restore the balance of gut microbiota by adjusting the relative abundance of bacteria both at the phylum and genus level, and these changes have been reported to be related to IR.

Methods

Sprague Dawley (SD) rats were fed a high-fat diet and were gavaged daily with either normal saline solution or PPM for 12 weeks. Major biochemical indexes, such as fasting blood glucose (FBG), fasting glucagon (FGC), total cholesterol (TC), and triglyceride (TG) were measured. Then the protein expression of adenosine 5′-monophosphate -activated protein kinase (AMPK) and G protein-coupled receptor 43 (GPR43) was evaluated by using Western blot analysis. Moreover, the composition of gut microbiota was assessed by analyzing 16S rRNA sequences.

Conclusions

Our findings showed that PPM reversed the increasing of FBG and the decreasing of IRI, PPM accelerated the expression of glucose metabolism-related proteins and regulated the intestinal microecological balance. Therefore, we hold the opinion that PPM may be an effective option for treating IR.

High glucose upregulates myosin light chain kinase to induce microfilament cytoskeleton rearrangement in hippocampal neurons

Chronic hyperglycemia leads to myosin light chain kinase (MLCK) upregulation and induces neuronal damage. However, the underlying molecular mechanism of neuronal damage in hyperglycemia has not yet been fully elucidated. In the present study, hippocampal neuronal cells were cultured and treated with a high glucose concentration (45 mmol/l). The results demonstrated that high glucose induced shrinking of the synapses, nuclear shape irregularity and microfilament damage. Filamentous actin (F‑actin) filaments were rearranged, cell apoptosis rate was increased and the protein expression of MLCK and phosphorylated (p)‑MLC was upregulated. The MLCK inhibitor ML‑7 largely reversed the alterations in the microfilament cytoskeleton, inhibited F‑actin depolymerization, reduced apoptosis and downregulated MLCK and p‑MLC protein expression. Overall, these results indicated that high glucose upregulated MLCK to promote F‑actin depolymerization, which induced microfilament cytoskeleton rearrangement in hippocampal neuronal cells.

Discrimination of Radix Polygoni Multiflori from different geographical areas by UPLC-QTOF/MS combined with chemometrics

Background

Nowadays, Radix Polygoni Multiflori (RPM, Heshouwu in Chinese) from different geographical origins were used in clinic. In order to characterize the chemical profiles of different geographical origins of RPM samples, ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF/MS) combined with chemometrics (partial least squared discriminant analysis, PLS‑DA) method was applied in the present study.

Methods

The chromatography, chemical composition and MS information of RPM samples from 18 geographical origins were acquired and profiled by UPLC-QTOF/MS. The chemical markers contributing the differentiation of RPM samples were observed and characterized by supervised PLS‑DA method of chemometrics.

Results

The chemical composition differences of RPM samples derived from 18 different geographical origins were observed. Nine chemical markers were tentatively identified which could be used as specific chemical markers for the differentiation of geographical RPM samples.

Conclusions

UPLC-QTOF/MS method coupled with chemometrics analysis has potential to be used for discriminating different geographical TCMs. Results will help to develop strategies for conservation and utilization of RPM samples.

Electronic supplementary material

The online version of this article (10.1186/s13020-017-0155-8) contains supplementary material, which is available to authorized users.

Discrimination of Polygoni Multiflori radix and Cynanchi Auriculati radix using ultra-high performance liquid chromatography fingerprints and chemical pattern recognition

In this work, a strategy was proposed to discriminate Polygoni Multiflori Radix (PMR) and its adulterant (Cynanchi Auriculati Radix, CAR). Ultra-high performance liquid chromatography (UHPLC) fingerprints were established to analyze samples containing PMR, CAR and mixtures simultaneously. Multivariate classification methods were applied to analyze the obtained UHPLC fingerprints, including principal component analysis (PCA), partial least square discriminant analysis (PLS-DA), soft independent modeling of class analogy (SIMCA), support vector machine discriminant analysis (SVMDA) and counter-propagation artificial neural network (CP-ANN). A plot of PCA score showed that PMR and CAR samples belonged to separate clusters (PMR class and CAR class), and samples of mixtures were located near PMR or CAR classes. Analysis by PLS-DA, SVMDA and CP-ANN performed well for recognition and prediction in terms of PMR and CAR samples. Moreover, the PLS-DA method performed best in the detection of adulterated samples, even if the adulterant was about 25%.