A Bioactivity-Based Method for Screening, Identification of Lipase Inhibitors, and Clarifying the Effects of Processing Time on Lipase Inhibitory Activity of Polygonum Multiflorum

Identification and localization of morphological feature-specific metabolites in Reynoutria multiflora roots

Reynoutria multiflora roots are a classical herbal medicine with unique nourishing therapeutic effects. Anomalous vascular bundle (AVB) forming "cloudy brocade patterns" is a typical morphological feature of R. multiflora roots and has been empirically linked to its quality classification. However, scientific evidence, especially for AVB-specific specialised metabolites, has not been comprehensively revealed thus far. Herein, desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) analysis was applied to carry out an in situ analysis of specialised metabolites distributed specifically at the AVB and cork of R. multiflora roots. To enlarge the scope of compounds by DESI detection, various solvent systems including acetone, acetonitrile, methanol, and water were used to assist in the discoveries of 40 specialised metabolites with determined localization. A series of bioactive constituents including stilbenes, flavonoids, anthraquinones, alkaloids, and naphthalenes were found specifically around the brocade patterns. Notably, phospholipids were detected from R. multiflora roots by in situ analysis for the first time and were found mainly in the phloem of AVB (PAB). This is the first study to use gradient solvent systems in DESI-MSI analysis to locate the specialised metabolites distribution. The discovery of feature-specific compounds will bridge the empirical identification to precision quality control of R. multiflora roots.

Recent advances on discovery of enzyme inhibitors from natural products using bioactivity screening

The essence of enzymes is to keep the homeostasis and balance of human by catalyzing metabolic responses and modulating cell. Suppression of enzyme slows the progress of some diseases, making it a therapeutic target. Therefore, it is important to develop enzyme inhibitors by proper bioactivity screening strategies for the future treatment of some major diseases. In this review, we summarized the recent (2015-2020) applications of several screening strategies (electrophoretically mediated microanalysis, enzyme immobilization, affinity chromatography, and affinity ultrafiltration) in finding enzyme inhibitors from certain species of bioactive natural compounds of plant origin (flavonoids, alkaloids, phenolic acids, saponins, anthraquinones, coumarins). At the same time, the advantages and disadvantages of each strategy were also discussed, and the future possible development direction in enzyme inhibitor screening has prospected. To sum up, it is expected to help readers select suitable screening strategies for enzyme inhibitors and provide useful information for the study of the biological of specific kinds of natural products. This article is protected by copyright. All rights reserved.

Pharmacokinetics, Tissue Distribution, and Excretion Characteristics of a Radix Polygoni Multiflori Extract in Rats

Although progress has been achieved in the pharmacological activity and toxicity of Radix Polygoni Multiflori (RPM), the chemical basis of its toxicity is still unclear. Here, we performed a multicompound pharmacokinetic analysis and investigated the tissue distribution and excretion characteristics of RPM components after oral administration in rats. The findings demonstrated that the active ingredients of the RPM extract were quickly absorbed after oral administration, with high exposure levels of emodin, 2,3,5,4′-teterahydroxystilbene-2-O-β-D-glucoside (TSG), citreorosein, torachrysone-8-O-glucoside (TG), emodin-8-O-β-D-glucoside (EG), and physcion-8-O-β-D-glucoside (PG). The tissue distributions of emodin, TSG, TG, EG, and PG were high in the liver and kidney. These components were the key contributors to the effectiveness and toxicity of RPM on the liver and kidney. Most of the active ingredients were mainly excreted through feces and bile, while a few were converted into other products in the body and excreted through urine and feces.

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.

Influence Factors on the Hepatotoxicity of Polygoni Multiflori Radix

Background

Chinese herbal medicine (CHM) with reported hepatotoxicity is identified, in which Polygoni Multiflori Radix (HSW) attracts most attention. According to the Traditional Chinese Medicine (TCM) theory, processing is believed to be able to reduce the toxicity of HSW, but in publications, both processed and unprocessed HSW are reported to cause liver injury.

Methods

This article reviews the case reports and experimental researches involving liver damage associated with HSW from the following aspects: clinical features, hepatic toxicity components, hepatotoxicity mechanism, and so on.

Results

HSW has hepatotoxicity in different degrees and even leads to death, and the reason is multioriginal.

Conclusions

People should be educated to have a broad understanding on ensuring drug use safety and lower drug-induced risks when taking HSW preparations.

Rapid Discovery of the Potential Toxic Compounds in Polygonum multiflorum by UHPLC/Q-Orbitrap-MS-Based Metabolomics and Correlation Analysis

The dry roots of Polygonum multiflorum (PM), involving both the raw and processed materials, are widely used as the traditional Chinese medicine for treating various diseases in China. Hepatotoxicity has been occasionally reported in patients who consume PM. Unfortunately, no definite criteria are currently available regarding the processing technology of PM for reduction the toxicity. In this work, we aimed to investigate the variations of PM metabolite profiles induced by different processing technologies by UHPLC/Q-Orbitrap-MS and multivariate statistical analysis, and to discover the potential toxic compounds by correlating the cytotoxicity of L02 cell with the contents of metabolites in raw and processed PM samples. We could identify two potential toxic compounds, emodin-8-O-glucoside and torachrysone-O-hexose, which could be selected as the toxic markers to evaluate different processing methods. The results indicated all processed PM samples could decrease the cytotoxicity on L02 cell. The best processing technology for PM process was to steam PM in black soybean decoction (BD-PM) for 24 h.

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.

Chemical Constituents of Smilax china L. Stems and Their Inhibitory Activities against Glycation, Aldose Reductase, α-Glucosidase, and Lipase

The search for natural inhibitors with anti-diabetes properties has gained increasing attention. Among four selected Smilacaceae family plants, Smilax china L. stems (SCS) showed significant in vitro anti-glycation and rat lens aldose reductase inhibitory activities. Bioactivity-guided isolation was performed with SCS and four solvent fractions were obtained, which in turn yielded 10 compounds, including one phenolic acid, three chlorogenic acids, four flavonoids, one stilbene, and one phenylpropanoid glycoside; their structures were elucidated using nuclear magnetic resonance and mass spectrometry. All solvent fractions, isolated compounds, and stem extracts from plants sourced from six different provinces of South Korea were next tested for their inhibitory effects against advanced glycation end products, as well as aldose reductase. α-Glucosidase, and lipase assays were also performed on the fractions and compounds. Since compounds 3, 4, 6, and 8 appeared to be the superior inhibitors among the tested compounds, a comparative study was performed via high-performance liquid chromatography with photodiode array detection using a self-developed analysis method to confirm the relationship between the quantity and bioactivity of the compounds in each extract. The findings of this study demonstrate the potent therapeutic efficacy of SCS and its potential use as a cost-effective natural alternative medicine against type 2 diabetes and its complications.