Stilbenes with Potent Protein Tyrosine Phosphatase-1B Inhibitory Activity from the Roots of Polygonum multiflorum

Evaluating the anticancer potential of Polygonum multiflorum root-derived stilbenes against H2452 malignant pleural mesothelioma cells

A naturally occurring stilbene, resveratrol, shows promising effects in the treatment of malignant pleural mesothelioma (MPM) both as a single agent and in combination with chemotherapeutic drugs. To discover new anticancer agents targeting MPM, stilbene-targeted isolation was performed on the roots of Polygonum multiflorum Thunb., an herbal medicine rich in stilbene compounds. In this study, seven stilbene glycosides (1-7) were isolated, along with four non-stilbenes (8-11), of which compounds 4 and 9-11 have not previously been isolated from this species. Stiquinoside A (1) is a previously undescribed stilbene glycoside, and its structure was elucidated as (E)-2,3,5,4'-tetrahydroxystilbene 2-O-β-d-quinovopyranoside based on 1D and 2D-NMR, HR-ESI-MS, and acid hydrolysis experiments. Compounds 1, 4, 6, and 8 significantly inhibit the growth of MPM cancer cells H2452. These results demonstrate the potential utility of stilbenes in new strategies for the treatment of MPM.

Phytochemistry, pharmacology, toxicology and detoxification of Polygonum multiflorum Thunb.: a comprehensive review

Background

Polygonum multiflorum Thunb. (PM), a kind of perennial plant, belongs to the genus Polygonum of the family polygonaceae.The dry root of PM (also called Heshouwu), is a traditional Chinese medicine, which has a series of functions and is widely used in clinic for hair lossing, aging, and insomnia. While, PM also has some toxicity, its clinical drug safety has been concerned. In this paper, the chemical components, toxic mechanisms and detoxification strategies of PM were reviewed in order to provide evidence for its clinical application.

Materials and methods

We conducted a systematic review of published literature of PM, including English and Chinese databases, such as PubMed, Web of Science, CNKI, and Wanfang.

Results

PM contains a variety of chemical compounds, including stilbenes, quinones, flavonoids, phospholipids, and has many pharmacological activities such as anti-aging, wound healing, antioxidant, and anti-inflammatory properties. The PE has certain therapeutic effect, and it has certain toxicity like hepatotoxicity, nephrotoxicity, and embryotoxicity at the same time, but.these toxic effects could be effectively reduced by processing and compatibility.

Conclusion

It is necessary to further explore the pharmacological and toxicological mechanisms of the main active compounds of PE.This article provides scientific basis for the safe clinical application of PM.

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.

On-line identification of the chemical constituents of Polygoni Multiflori Radix by UHPLC-Q-ToF MS/MS

Introduction: Polygoni Multiflori Radix (PMR) is a type of Chinese herbal medicine with rich chemical composition and pharmacological activity used widely in medicine and food. However, in recent years, there have been increasing numbers of negative reports about its hepatotoxicity. Identification of its chemical constituents for quality control and safe use is very important. Methods: Three solvents of different polarities (water, 70% ethanol, and 95% ethanol solution) were used to extract the compounds from PMR. Extracts were analyzed and characterized by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-ToF MS/MS) in the negative-ion mode. Results: 152 compounds were detected and identified: 50 anthraquinones, 33 stilbene derivatives, 21 flavonoids, seven naphthalene compounds, and 41 other compounds. Eight other compounds were reported for the first time in the PMR-related literature, and eight other compounds were potentially new compounds. Discussion: This study lays a solid foundation for the screening of toxicity and quality-control indicators of PMR.

In Vitro and in Silico Analysis of Phytochemicals From Fallopia dentatoalata as Dual Functional Cholinesterase Inhibitors for the Treatment of Alzheimer’s Disease

Current studies have found that butyrylcholinesterase (BuChE) replaces the biological function of acetylcholinesterase (AChE) in the late stage of Alzheimer’s disease. Species in the genus of Fallopia, rich in polyphenols with diverse chemical structures and significant biological activities, are considered as an important resource for screening natural products to against AD. In this study, thirty-four compounds (1–34) were isolated from Fallopia dentatoalata (Fr. Schm.) Holub, and their inhibitory effects against AChE and BuChE were assessed. Compounds of the phenylpropanoid sucrose ester class emerged as the most promising members of the group, with 31–33 displaying moderate AChE inhibition (IC50 values ranging from 30.6 ± 4.7 to 56.0 ± 2.4 µM) and 30–34 showing potential inhibitory effects against BuChE (IC50 values ranging from 2.7 ± 1.7 to 17.1 ± 3.4 µM). Tacrine was used as a positive control (IC50: 126.7 ± 1.1 in AChE and 5.5 ± 1.7 nM in BuChE). Kinetic analysis highlighted compounds 31 and 32 as non-competitive inhibitors of AChE with Ki values of ∼30.0 and ∼34.4 µM, whilst 30–34 were revealed to competitively inhibit BuChE with Ki values ranging from ∼1.8 to ∼17.5 µM. Molecular binding studies demonstrated that 30–34 bound to the catalytic sites of BuChE with negative binding energies. The strong agreement between both in vitro and in silico studies highlights the phenylpropanoid sucrose esters 30–34 as promising candidates for use in future anti-cholinesterase therapeutics against Alzheimer’s disease.

Anti-Inflammatory Lignans from the Roots of Asarum heterotropoides var. mandshuricum and Their Mechanism of Action

Bioassay-guided fractionation of Asarum heterotropoides var. mandshuricum F. Maekawa (Aristolochiaceae) root extract led to the isolation and characterization of one new ferulic acid glucose ester (1) and nine known lignans (2-10). Their structures were elucidated using extensive spectroscopic methods, including 1D and 2D NMR, and MS spectra. The anti-inflammatory effects of the isolated compounds were investigated via their inhibition against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 mouse macrophage cells. Among them, compound 7 ((1R,2S,5R,6R)-5'-O-methylpluviatilol) showed the most effective inhibitory activity against NO production and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein in an exceedingly dose-dependent manner. In addition, further study revealed that the mechanism of anti-inflammatory activity of the most active lignan (7) might be associated with the inhibition of extracellular-signal-regulated kinase (ERK) and nuclear factor kappa B (NF-κB) phosphorylation.

PTP1B and α-glucosidase inhibitory activities of the chemical constituents from Hedera rhombea fruits: Kinetic analysis and molecular docking simulation

In this study, we present the first investigation of Hedera rhombea Bean fruit, which led to the isolation of six undescribed compounds including two megastigmane glucosides, two rare 1,4-dioxane neolignanes, and two quinic acid derivatives, together with 26 known compounds. Their structures and absolute configurations were elucidated by extensive analysis of NMR spectroscopic data, HRMS, and ECD calculations. This is the first report on the isolation of methyl 3-O-caffeoyl-5-O-p-coumaroylquinate from a natural source. Among the isolated compounds, falcarindiol and caffeoyltryptophan showed significant PTP1B inhibition with IC₅₀ values of 7.32 and 16.99 μM, respectively, compared to those of the positive controls [sodium orthovanadate (IC₅₀ = 17.96 μM) and ursolic acid (IC₅₀ = 4.53 μM)]. These two compounds along with several other compounds displayed significant α-glucosidase inhibitions with IC₅₀ values ranging from 12.88 to 91.89 μM, stronger than that of the positive control (acarbose, IC₅₀ = 298.07 μM). Enzyme kinetic analysis indicated that caffeoyltryptophan and falcarindiol displayed competitive and mixed-type PTP1B inhibition, respectively, whereas the α-glucosidase inhibition type was mixed-type for caffeoyltryptophan and uncompetitive (rarely reported for a-glucosidase inhibitors) for falcarindiol. In addition, molecular docking results showed that these active compounds exhibited good binding affinities toward both PTP1B and α-glucosidase with negative binding energies. The results of the present study demonstrate that these active compounds might be beneficial in the treatment of type 2 diabetes.

PTP1B inhibition studies of biological active phloroglucinols from the rhizomes of Dryopteris crassirhizoma: Kinetic properties and molecular docking simulation

By various chromatographic methods, 30 phloroglucinols (1-30) were isolated from a methanol extract of Dryopteris crassirhizoma, including two new dimeric phloroglucinols (13 and 25). The structures of the isolates were confirmed by HR-MS, 1D, and 2D NMR as well as by comparison with the literature. The protein tyrosine phosphatase 1B (PTP1B) effects of the isolated compounds (1-30) were evaluated using sodium orthovanadate and ursolic acid as a positive control. Among them, trimeric phloroglucinols 26-28 significantly exhibited the PTP1B inhibitory effects with the IC₅₀ values of 1.19 ± 0.13, 1.00 ± 0.04, 1.23 ± 0.05 μM, respectively. In addition, the kinetic analysis revealed compounds 26-28 acted as competitive inhibitors against PTP1B enzyme with K_i values of 0.63, 0.61, 1.57 μM, respectively. Molecular docking simulations were performed to demonstrate that these active compounds can bind with the catalytic sites of PTP1B with negative binding energies and the results are in accordance with that of the kinetic studies. In vitro and in silico results suggest that D. crassirhizoma rhizomes together with compounds 26-28 are potential candidates for treating type 2 diabetes.

Anti-Wrinkle Effect of Isatis indigotica Leaf Extract: Evaluation of Antioxidant, Anti-Inflammation, and Clinical Activity

Isatis indigotica leaf is an oriental herbal medicine that has been known for various pharmacological effects. However, its anti-wrinkle activity has not been fully evaluated. Therefore, we evaluated the anti-wrinkle effect of I. indigotica leaf extract on human skin. The purified extract inhibited 85.4% of 2,2-diphenyl-1-1picrylhydrazyl and 72.2% of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals at a concentration of 1 mg/mL. Nitrite production was reduced by 30% after treatment with 50 μg/mL of extract. Three fractions from the extract downregulated the mRNA expression of matrix metalloproteinase-1 and -3 and upregulated the expression of interleukin 4. Among the three fractions, fraction 2 exhibited the highest activity. The major component of the extract was identified as 3,4,5-trimethoxycinnamic acid by liquid chromatography coupled with mass spectrometry. Molecular docking was conducted to predict the binding mechanism of 3,4,5-trimethoxycinnamic with matrix metalloproteinase-1 and -3, and their binding energies were -5.20 and -4.89 kcal/mol, respectively. In a clinical trial, five roughness values of visiometer and visual score were significantly reduced in treated groups compared with the placebo group after 8 weeks. I. indigotica leaf extract inhibits wrinkle formation, and could be a potential anti-wrinkle agent. This is the first clinical trial demonstrating its anti-wrinkle 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.

Advances in the Study of the Potential Hepatotoxic Components and Mechanism of Polygonum multiflorum

The roots of Polygonum multiflorum (PM) (He Shou Wu in Chinese) are one of the most commonly used tonic traditional Chinese medicines (TCMs) in China. PM is traditionally valued for its antiaging, liver- and kidney-tonifying, and hair-blackening effects. However, an increasing number of hepatotoxicity cases induced by PM attract the attention of scholars worldwide. Thus far, the potential liver injury compounds and the mechanism are still uncertain. The aim of this review is to provide comprehensive information on the potential hepatotoxic components and mechanism of PM based on the scientific literature. Moreover, perspectives for future investigations of hepatotoxic components are discussed. This study will build a new foundation for further study on the hepatotoxic components and mechanism of PM.

Inhibition of PTP1B by farnesylated 2-arylbenzofurans isolated from Morus alba root bark: unraveling the mechanism of inhibition based on in vitro and in silico studies

Among the 2-arylbenzofuran derivatives isolated from Morus alba, the farnesylated 2-arylbenzofuran is a rarer constituent. The derivative has been reported to exert anti-obesity effect; however, its inhibitory effect on protein tyrosine phosphatase 1B (PTP1B) has not been investigated. In the previous study, the presence of the farnesyl group in the structure of 2-arylbenzofurans was found to have positive influences on their pancreatic lipase inhibitory activity. In the present study, we have confirmed the authenticity of the notation based on the PTP1B inhibitory activity of farnesylated 2-arylbenzofurans. Specifically, two farnesylated 2-arylbenzofurans [morusalfurans B (2) and C (3)] showed strong inhibitory effects on PTP1B with IC₅₀ values of 8.92 and 7.26 µM, respectively, which was significantly higher than that of the positive controls [sodium orthovanadate (IC₅₀ = 15.10 µM) and ursolic acid (IC₅₀ = 11.34 µM)]. Besides, two 2-arylbenzofurans [morusalfurans A (1) and F (6)], one flavonoid [morusalnol B (9)], and one geranylated stilbene [morusibene A (11)] exhibited PTP1B inhibition with IC₅₀ values ranging from 11.02 to 26.56 µM. Kinetic studies revealed compounds 2, 3, 6, and 11 as mixed type PTP1B inhibitors, while 1 and 9 are known as noncompetitive. Molecular docking simulations demonstrated that these active compounds can bind with the respective catalytic or/and allosteric sites of PTP1B with negative binding energies and the results are in accordance with that of the kinetic studies. To the best of our knowledge, this is the first time, the PTP1B inhibitory activity of eleven compounds (1–11), as well as the mechanism of action underlying the effects on PTP1B enzyme of the active compounds, were investigated. In vitro and in silico results suggest that the farnesylated 2-arylbenzofurans from M. alba may potentially be utilized as an effective treatment therapy for type 2 diabetes mellitus and its associated complications.

Multiflorumisides HK, stilbene glucosides isolated from Polygonum multiflorum and their in vitro PTP1B inhibitory activities

A phytochemical study on a 70% EtOH extract of dried roots of Polygonum multiflorum resulted in the isolation of four undescribed stilbene glucosides, namely multiflorumisides HK (1-4). The structures of the natural products were elucidated by 1D and 2D nuclear magnetic resonance (NMR) as well as mass spectroscopy analyses. Among them, multiflorumiside J (3) and multiflorumiside K (4) belong to rare tetramer stilbene glucosides. Moreover, the in vitro inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) were evaluated and the putative biosynthetic pathway was proposed. Notably, compounds 1-4 showed the inhibitory activity against PTP1B with the IC₅₀ values of 1.2, 1.7, 1.5 and 4.6 μm, respectively. Based on the obtained results, stilbene glucosides could be the potential PTP1B inhibitors of P. multiflorum.

Antioxidant and Antidiabetic Activities of Flavonoid Derivatives from the Outer Skins of Allium cepa L

The onion, known as the bulb onion or common onion, is not only a key ingredient in many tasty and healthy vegetarian meals but also many traditional medicines. Nine new flavonoids [cepaflavas A, B (5, 6), cepadials A-D (7-9 and 14), and cepabiflas A-C (10-12)] and six known compounds (1-4, 13, 15) were obtained from the outer skins of Allium cepa L. Among them, compounds 5, 6, and 9 might be artificial products formed during extraction and isolation. New compounds were structurally elucidated using various spectroscopy/spectrometry techniques, including NMR and HRMS, and computational methods. Their absolute configurations were determined using time-dependent density functional theory calculations, combined with ECD spectroscopy, optical rotation calculation, and statistical procedures (CP3 and DP4 analysis). The free radical scavenging assays revealed that the new compounds 10-12 possessed considerable antioxidant activities with IC₅₀ values of 4.25-8.88 and 7.12-8.14 μM against DPPH and ABTS^•+, respectively. Compounds 13-15 showed substantial inhibitory activities against both α-glucosidase and protein tyrosine phosphatase 1B (PTP1B), with IC₅₀ values of 0.89-6.80 and 1.13-6.82 μM, respectively. On the basis of molecular docking studies, 13 and 15 were predicted to have high binding capacity and strong affinity toward the active site of PTP1B.