Integrated chemometric fingerprints of antioxidant activities and HPLC-DAD-CL for assessing the quality of the processed roots of Polygonum multiflorum Thunb. (Heshouwu)

Processing of Reynoutria multiflora: transformation of catechin and gallic acid derivatives and their identification

Introduction: The root of Reynoutria multiflora (Thunb.) Moldenke (RM) has been used widely in formulations of herbal medicines in China for centuries. Raw R. multiflora (RRM) should be processed before use to reduce toxicity and increase efficacy. However, detailed regulation of the processing endpoint is lacking, and the duration of processing can vary considerably. We conducted in-depth research on stilbene glycosides in RM at different processing times. Previously, we discovered that 219 stilbene glycosides changed markedly in quantity and content. Therefore, we proposed that processing causes changes in various chemical groups. Methods: To better explain the mechanism of RM processing for toxicity reduction and efficacy enhancement, we used a method of tandem mass spectrometry described previously to research gallic acid based and catechin based metabolites. Results: A total of 259 metabolites based on gallic acid and 112 metabolites based on catechins were identified. Among these, the peak areas of 157 gallic acid and 81 catechins gradually decreased, those of another 71 gallic acid and 30 catechins first increased and then decreased, those of 14 gallic acid and 1 catechin gradually increased. However, 17 of the gallic acids showed no significant changes. We speculate that many gallic acid metabolites hydrolyze to produce gallic acid; moreover, the dimers/trimers of catechins, after being cleaved into catechins, epicatechin, gallic acid catechins, and epicatechin monomers, are cleaved into gallic acid and protocatechualdehyde under high temperature and high humidity, subsequently participating in the Maillard reaction and browning reactions. Discussion: We showed that processing led to changes in chemical groups, clarification of the groups of secondary metabolites could provide a basis for research on the pharmacological and toxic mechanisms of RM, as well as the screening of related markers.

Reliability evaluation of traditional Chinese medicine fingerprints combined with qualitative and quantitative analysis and antioxidant activity to comprehensively evaluate the quality of Citri Reticulatae Pericarpium

Comprehensive evaluation of Citri Reticulatae Pericapium quality by HPLC, UV and antioxidant activity.

Metabolomics Approach for Discrimination and Quality Control of Natural and Commercial Fallopia multiflora Products in Vietnam

A precise HPLC-DAD-based quantification together with the metabolomics statistical method was developed to distinguish and control the quality of Fallopia multiflora, a popular medicinal material in Vietnam. Multivariate statistical methods such as hierarchical clustering analysis and principal component analysis were utilized to compare and discriminate six natural and twelve commercial samples. 2,3,4′,5-Tetrahydroxystilbene 2-O-β-D-glucopyranoside (THSG) (1), emodin (4), and the new compound 6-hydroxymusizin 8-O-α-D-apiofuranosyl-(1⟶6)-β-D-glucopyranoside (5) could be considered as important markers for classification of F. multiflora. Furthermore, seven phenolics were quantified that the variation in the contents of selected metabolites revealed the differences in the quality of natural and commercial samples. Recovery of the compounds from the analytes was more than 98%, while the limits of detection (LOD) and the limits of quantitation (LOQ) ranged from 0.5 to 6.6 μg/ml and 1.5 to 19.8 μg/ml, respectively. The linearity, LOD, LOQ, precision, and accuracy satisfied the criteria FDA guidance on bioanalytical methods. Overall, this method is a promising tool for discrimination and quality assurance of F. multiflora products.

New progress in the pharmacology of protocatechuic acid: A compound ingested in daily foods and herbs frequently and heavily

Protocatechuic acid is a natural phenolic acid, which widely exists in our daily diet and herbs. It is also one of the main metabolites of complex polyphenols, such as anthocyanins and proanthocyanins. In recent years, a large number of studies on the pharmacological activities of protocatechuic acid have emerged. Protocatechuic acid has a wide range of pharmacological activities including antioxidant, anti-inflammatory, neuroprotective, antibacterial, antiviral, anticancer, antiosteoporotic, analgesia, antiaging activties; protection from metabolic syndrome; and preservation of liver, kidneys, and reproductive functions. Pharmacokinetic studies showed that the absorption and elimination rate of protocatechuic acid are faster, with glucuronidation and sulfation being the major metabolic pathways. However, protocatechuic acid displays a dual-directional regulatory effect on some pharmacological activities. When the concentration is very high, it can inhibit cell proliferation and reduce survival rate. This review aims to comprehensively summarize the pharmacology, pharmacokinetics, and toxicity of protocatechuic acid with emphasis on its pharmacological activities discovered in recent 5 years, so as to provide more up-to-date and thorough information for the preclinical and clinical research of protocatechuic acid in the future. Moreover, it is hoped that the clinical application of protocatechuic acid can be broadened, giving full play to its characteristics of rich sources, low toxicity and wide pharmacological activites.

A Candidate Drug for Nonalcoholic Fatty Liver Disease: A Review of Pharmacological Activities of Polygoni Multiflori Radix

Nonalcoholic fatty liver disease, a type of metabolic syndrome, continues to rise globally. Currently, there is no approved drug for its treatment. Improving lifestyle and exercise can alleviate symptoms, but patients' compliance is poor. More and more studies have shown the potential of Polygoni Multiflori Radix (PMR) in the treatment of NAFLD and metabolic syndrome. Therefore, this paper reviews the pharmacological effects of PMR and its main chemical components (tetrahydroxystilbene glucoside, emodin, and resveratrol) on NAFLD. PMR can inhibit the production of fatty acids and promote the decomposition of triglycerides, reduce inflammation, and inhibit the occurrence of liver fibrosis. At the same time, it maintains an oxidation equilibrium status in the body, to achieve the therapeutic purpose of NAFLD and metabolic syndrome. Although more standardized studies and clinical trials are needed to confirm its efficacy, PMR may be a potential drug for the treatment of NAFLD and its complications. However, the occurrence of adverse reactions of PMR has affected its extensive clinical application. Therefore, it is necessary to further study its toxicity mechanism, enhance efficacy and control toxicity, and even reduce toxicity, which will contribute to the safe clinical use of PMR.

Metabolomics profiling of Polygoni Multiflori Radix and Polygoni Multiflori Radix Preparata extracts using UPLC-Q/TOF-MS

Background

The side effects caused by Polygoni Multiflori Radix (PMR) and Polygoni Multiflori Radix Praeparata (PMRP) have often appeared globally. There is no research on the changes of endogenous metabolites among PMR- and PMRP-treated rats. The aim of this study was to evaluate the varying metabolomic effects between PMR- and PMRP-treated rats. We tried to discover relevant differences in biomarkers and endogenous metabolic pathways.

Methods

Hematoxylin and eosin staining and immunohistochemistry staining were performed to find pathological changes. Biochemical indicators were also measured, one-way analysis of variance with Dunnett’s multiple comparison test was used for biochemical indicators comparison among various groups. Metabolomics analysis based on ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q/TOF-MS) was performed to find the changes in metabolic biomarkers. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to reveal group clustering trend, evaluate and maximize the discrimination between the two groups. MetaboAnalyst 4.0 was performed to find and confirm the pathways.

Results

PMR extracts exhibited slight hepatotoxic effects on the liver by increasing aspartate and alanine aminotransferase levels. Twenty-nine metabolites were identified as biomarkers, belonging to five pathways, including alpha-linolenic acid metabolism, taurine and hypotaurine metabolism, glycerophospholipid metabolism, arginine and proline metabolism, and primary bile acid biosynthesis.

Conclusion

This study provided a comprehensive description of metabolomic changes between PMR- and PMRP-treated rats. The underlying mechanisms require further research.

Profile of Bioactive Compounds in the Morphological Parts of Wild Fallopia japonica (Houtt) and Fallopia sachalinensis (F. Schmidt) and Their Antioxidative Activity

The aim of this study was to determine the content of triterpenoids and polyphenols, and antioxidative activity in leaves, stalks, and roots of plants from the species Fallopia as well as to present the main relationship between them. Polyphenolic compounds and triterpenoids were identified with liquid chromatography-photodiode detector-mass spectrometry/quadrupole time of flight (LC-MS-Q/TOF; qualitatively) and quantified with an ultra-performance liquid chromatography-photodiode detector (UPLC-PDA (quantitatively), and their antioxidative activity was determined with radical scavenging capacity (ABTS) and oxygen radical absorbance capacity (ORAC) assays. Generally, the wild Fallopia japonica Houtt. species had 1.2 times higher content of bioactive compounds and antioxidative activity than Fallopia sachalinensis. Contents of polyphenolic compounds determined in leaves, stalks, and roots were on average 17.81, 10.60, and 9.02 g/100 g of dry weight (DW), whereas the average contents of triterpenoids reached 0.78, 0.70, and 0.50 g/100 g DW, respectively. The leaves were a better source of polymeric procyanidins, phenolic acids, flavones, and flavonols, as well as oleanolic and ursolic acids than the other morphological parts of the tested plants. However, the roots were an excellent source of flavan-3-ols (monomeric and oligomer) and stilbenes, such as resveratrol, and their derivatives. The results obtained showed significant differences between plants of the wild Fallopia species and their morphological parts, and enabled selecting the most valuable morphological part of the tested plants to be used for food enrichment and nutraceuticals production. Therefore, the leaves seem to be the best as potential food additives for health, due to the above-average content of polyphenolic compounds and triterpenoids. In turn, roots, with their high contents of stilbenes and polyphenolic compounds, represent a good material for the medical, pharmaceutical, and cosmetic industries. The principal component analysis of the plants of wild Fallopia species and their morphological parts confirmed significant differences in their chemical composition.

Tetrahydroxystilbene glycoside antagonizes β-amyloid-induced inflammatory injury in microglia cells by regulating PU.1 expression

Inhibiting β-amyloid (Aβ)-induced microglial activation is proposed as an effective strategy for the treatment of Alzheimer’s disease. Tetrahydroxystilbene glycoside (TSG) is the main active ingredient of Polygonum multiflorum and has a wide range of biological properties, including antiinflammation. Here, we focused on the function and regulatory mechanism of TSG in Aβ-induced N9 and BV2 cells. The results showed that Aβ treatment induced the activation of microglia cells and the production of inflammatory molecules, including inducible nitric oxide synthase, nitric oxide, cyclooxygenase 2, and prostaglandin E2, which were significantly inhibited by TSG pretreatment. Furthermore, we found Aβ exposure increased the levels of microglial M1 markers, interleukin (IL)-1β, IL-6, and tumor necrosis factor α, and the pretreatment of TSG suppressed the increase of M1 markers and enhanced the levels of M2 markers, including IL-10, brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, and arginase-1. PU.1 overexpression was found to eradicate the anti-inflammatory effects of TSG in Aβ-induced microglial cells. Taken together, these findings indicate that TSG attenuates Aβ-induced microglial activation and polarizes microglia towards M2 phenotype, which may be closely associated with the regulation of PU.1.

Integrating Targeted and Untargeted Metabolomics to Investigate the Processing Chemistry of Polygoni Multiflori Radix

Polygoni Multiflori Radix (PMR, Heshouwu in Chinese), derived from the tuberous roots of Polygonum multiflorum Thunb., is a widely-used Chinese medicinal material. For traditional clinical use, raw PMR (RPMR) is processed by nine cycles of steaming and drying to generate processed PMR (PPMR); RPMR and PPMR have distinct medicinal purposes based on the theory of traditional Chinese medicine. While PMR has been processed for hundreds of years, including the present, the chemistry of that processing has not been well studied. In this study, targeted and untargeted metabolomics analyses using ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) and ultra-performance liquid chromatography-quadrupole/triple quadrupole mass spectrometry (UPLC-QqQ-MS/MS) were integrated to investigate the processing chemistry of PMR. The results demonstrate that processing by nine cycles of steaming and drying qualitatively and quantitatively alters the chemical profile of PMR. Several mechanisms, namely hydrolysis, dehydration, isomerization, and Maillard reaction appear to be involved in the chemical transformation that occurs. The qualitative and quantitative data further suggest that nine cycles might be necessary for the preparation of PPMR, as PPMR that has been processed nine times shows significant differences in its chemical profile.

Polygonum multiflorum Thunb.: A Review on Chemical Analysis, Processing Mechanism, Quality Evaluation, and Hepatotoxicity

Polygonum multiflorum Thunb. and its processed products have been used in China for centuries due to their multiple beneficial effects to human body. Currently, liver injuries caused by taking P. multiflorum have been reported worldwide, but the potential toxic components and possible mechanism that caused hepatotoxicity remain unclear. It is worth noting that the processing procedure could significantly decrease the toxicity of raw P. multiflorum and the processed products of P. multiflorum are considered to be relatively safe. However, the processing mechanism is still ambiguous, and there is the lack of a scientific approach to control the quality of P. multiflorum praeparata. This study is the first review that summarizes the recently advances (from 2007 to 2017) in the chemical analysis of P. multiflorum, and provides comprehensive information on the quantitative and qualitative analysis of P. multiflorum as well as its related species. In addition, the processing mechanism and quality evaluation of processed P. multiflorum are discussed. Moreover, the toxicity of P. multiflorum is analyzed from the perspectives of exploration of the proposed toxic ingredients, metabolite identification, metabolomics studies, and exogenous contaminant determination. Furthermore, trends and perspectives for future research of this medicine are discussed.

Effect of a stilbene glycoside-rich extract from Polygoni Multiflori Radix on experimental non-alcoholic fatty liver disease based on principal component and orthogonal partial least squares discriminant analysis

Polygoni Multiflori Radix is a traditional Chinese medicine used clinically to support the functions of the liver and kidneys and to treatment hyperlipidemia. In previous studies, an effective fraction, rich in 2,3,5,4′-tetrahydroxy stilbene-2-O-β-D-glucoside (TSG), was separated from Polygoni Multiflori Radix and demonstrated hypolipidemic activity. The present study aimed to systematically assess the effect of this fraction on non-alcoholic fatty liver disease (NAFLD). A NAFLD model was established by feeding Sprague-Dawley rats a high-fat diet with 10% fructose solution for 18 weeks. Hematoxylin and eosin staining was applied for hepatic histopathological analysis. In addition, enzyme activities, lipid metabolism, inflammatory factors and insulin resistance indices were measured using a fully automatic blood biochemistry analyser and ELISA. Furthermore, cytochrome P450 2E1 (CYP2E1) and peroxisome proliferator-activated receptor α (PPARα) mRNA and protein expression were evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analysis. Principal component analysis and orthogonal partial least squares discriminant analysis were used to analyse the data. The results revealed that the TSG-rich fraction (TSGP) significantly lowered the serum total cholesterol and triglyceride levels, and the liver free fatty acid, CYP2E1 mRNA and malondialdehyde levels, in addition to mitigating hepatic enlargement and alleviating liver steatosis. Furthermore, it upregulated PPARα mRNA expression in the liver tissue. The results indicated that TSGP exhibited a protective effect against NAFLD and the underlying mechanism may involve augmentation of anti-lipid peroxidation capacity via regulation of PPARα and CYP2E1-mediated pathways.

Mechanisms of Heshouwuyin in regulating apoptosis of testicular cells in aging rats through mitochondrial pathway

BACKGROUND

Polygonum multiflorum has important effects on anti-aging and immunity enhancement. Many traditional Chinese medicine preparations based on Polygonum multiflorum are widely used for the clinical prevention and treatment of aging. However the mechanisms of these herb mixtures are often unknown. This study investigates the effect of Heshouwuyin, a Chinese herbal compound for invigorating the kidney, on the regulation of testicular cells apoptosis in aging rats.

METHODS

In this study, 18-month-old Wistar rats served as a model of natural aging and 12-month-old rats served as a young control group. Heshouwuyin group 1 and group 2 were comprised 18-month-old rats given Heshouwuyin intragastrically for 60 days and 30 days respectively. Then testes of the young control group were isolated in the age of 12 months, the other three groups were in the age of 18 months.

RESULTS

TUNEL assay showed that the rate of testicular cell apoptosis was obviously higher and Flow cytometry analysis showed that the rate of cell proliferation was significantly lower in the natural aging group than in the young control group and that intervention with Heshouwuyin could reverse this phenomenon. Therefore, we further applied microarray analysis to screen out differentially expressed genes regulated by Heshouwuyin and related to cell apoptosis. The expression of these genes was observed by quantitative fluorescence PCR, immunofluorescence staining, and western blot. The results showed that the expression of 14-3-3σ was significantly lower and that the expression of DR6, BAX, caspase-3 and Cytc were significantly higher in the natural aging group than in the young control group, but intervention with Heshouwuyin significantly reversed this phenomenon. Moreover, the curative efficacy of Heshouwuyin after 60 days was better than that of Heshouwuyin after 30 days.

CONCLUSION

Our study suggests that Heshouwuyin has anti-aging effects on the testis by means of inhibiting the occurrence of apoptosis in spermatogenic cells, thus improving the spermatogenic function of the testis. This is mainly achieved by regulating the expression of key genes in the mitochondrial apoptosis pathway.