Three Anthraquinones Isolated from Aster tataricus L.f

The roots and rhizomes of Aster tataricus L. f (Zi-wan) is a traditionalChinese medicine, which has been used for relieving cough and resolving phlegm. Previousinvestigation of the species resulted in the isolation and identification of triterpenes,triterpenoid saponins, cyclic pentapeptides, and oligopeptides. We have also reported thepolyphenols and a dipeptide isolated from the species. In this paper, the isolation and structureelucidation of three anthraquinones, chrysophanol (1), physciori (2), and emodin (3), are described.Chrysophanol and physcion were isolated from family Composi-tae for the first time.

The Action of Aloe Anthraquinones in Protecting the Growth of Soybean from Ultraviolet Radiation Stress

In order to investigate the protective effect of aloe anthraquinones on growth and development of soybean against ultraviolet B radiation stress from the morphological structure and physio-chemical indices. The results showed that, stressed by the enhanced ultraviolet b radiation, the soybean gave a dwarfed plant, shrunken leaf area and decreased photosynthetic pigment, while an ascended MDA content. Spraying aloe anthraquinones effectively relieved the reductions of chloro- phyll content and biomass and decreased the production of MDA under the radia- tion of UV-B. Moreover, under the UV-B radiation, waxy substances on epidermal cells increased remarkably and the stomas showed obvious subsidence, while spraying aloe anthraquinones could maintain the structure and shape of cells similar to that under natural light, and the stomas subsidence as well.

Organ specific differences in alteration of aquaporin expression in rats treated with sennoside A,senna anthraquinones and rhubarb anthraquinones

OBJECTIVE Senna and rhubarb are classified as stimulative laxatives,and known to have similar effective constituents,the anthraquinones.Being protected by theβ-glucoside bond,the anthraquinones can reach the intestines where they are degraded into complex metabolites by enzymes secreted from the intestinal microbiome.It is these complex metabolites that produce the laxative effects.Then the similarities and differences of action between the anthraquinones require further elucidation.METHODS Here,we studied metabolites of senna anthraquinones(SAQ),rhubarb anthraquinones(RAQ)and their chemical marker,sennoside A(SA),in a rat diarrhea model.In the in vitro biotransformation experiments,SAQ,RAQ and SA were incubated with rat fecal flora solution and the metabolites produced were analyzed using HPLC.In the in vivo studies,the same compounds were investigated for purgation induction,with measurement of histopathology and multiple aquaporins(Aqps)gene expression in six organs.RESULTS SAQ and RAQ had similar principal constituents but could be degraded into different metabolites.A similar profile of Aqps down-regulation for all compounds was seen in the colon,suggesting a similar mechanism of action for purgation.However,in the kidneys and livers of the diarrhea-rats,down-regulation of Aqps was found in the RAQ-rats whereas up-regulation of Aqps was seen in the SAQ-rats.Furthermore,the RAQ-rats showed lower aquaporin 2(Aqp2)protein expression in the kidneys,whilst the SA-rats and SAQ-rats had higher Aqp2 protein expression in the kidneys.This may have implications for side effects of SAQ or RAQ in patients with chronic kidney or liver diseases.CONCLUSION SAQ and RAQ showed similar laxative actions with a similar mechanism,they could display different actions in rat kidneys and livers.We suggest that the clinical usage of senna or rhubarb products should be clarified for patients having chronic kidney or liver diseases.

Simultaneous determination of flavonoids and anthraquinones in chrysanthemum by capillary electrophoresis with amperometry detection

A high-performance capillary electrophoresis with amperometry detection method （CE-AD） has been developed for the analysis of flavonoids and anthraquinones （emodin, kaempferol, apigenin, luteolin and rhein） in chrysanthemum. Under optimum conditions, these five analytes were base-line separated within 17 min using a borate-phosphate running buffer （1.5 ×10^-2 mol/L borate-3× 10^-2 mol/L phosphate running buffer, pH 9.0） at a working potential of ＋0.90 V （vs. SCE） and a separation voltage of 19 kV. The linear relationship between concentration and current response was obtained with detection limits （S/N = 3） ranging from 1.0 × 10^-7 to 2.1 × 10^-7 g/mL for all analytes. This proposed method was successfully used in the analysis of four kinds of chrysanthemum with relatively simple extraction procedures, the assay results were satisfactory.

Processing of Rhubarb and Determination of Five Free Anthraquinones in Raw Rhubarb and Stewed Rhubarb

[Objectives]To determine the content of five kinds of free anthraquinones in raw rhubarb and stewed rhubarb by HPLC,and compare their content difference,so as to reveal the change rule of material basis before and after processing of traditional Chinese medicine.[Methods]The content was determined by HPLC with Thermo BDS HYPERSII C18 column(4.6 mm×250 mm,5μm)as chromatographic column and methanol-0.1%phosphoric acid(85∶15)aqueous solution as mobile phase;the detection wavelength was 256 nm,the flow rate was 1.0 mL/min,the column temperature was 30℃,and the injection volume was 10μL.[Results]Aloe-emodin,rhein,emodin,chrysophanol and emodin methyl ether showed a good linear relationship in the linear range of 0.0207-0.414(R2=0.9999),0.1721-3.442(R2=0.9996),0.0203-0.406(R2=0.9999),0.148-2.96(R2=0.9998)and 0.164-3.28(R2=0.9993),respectively;the content of aloe-emodin decreased by about 8.26%,and rhein decreased by about 9.21%;the content of emodin increased by about 16.44%,chrysophanol increased by about 16.12%,and emodin methyl ether increased by about 20.01%,indicating that the processing technology had different effects on the components of rhubarb.[Conclusions]The content of five free anthraquinones in rhubarb was affected to different degrees after processing,and this method could be used as a quality control method for rhubarb and its different processed products.

Study on the Intramolecular Hydrogen Bonds of Dibenzofurans, Xanthones and Anthraquinones with One or Two Positions Substituted by Hydroxyls

The thermodynamic properties of dibenzofurans （DFs）, xanthones （XTs） and an-thraquinones （AQs） with one and two positions substituted with hydroxyls in the ideal gas state at 298.15 K and 1.013×10^5 pa were calculated at the B3LYP/6-311G^＊ level using Gaussian 03 program. The isodesmic reactions were designed to calculate the standard free energy of formation （△fG^θ）. Three types of hydrogen bonds exist in the three kinds of chemicals and their bond energies were ascertained as 7-15, 15-23 and 49-58 kJ·mo1^-1 respectively by comparing the △fG^θ values. Electronic density topology analysis was applied to validate the strength of bond.

Three New Anthraquinones from Polygonum cillinerve

Three new anthraquinones, emodin-8-β-D-（2＂-O-coumarate）glucoside 1, emodin-8-β-D-（6＇-O-acetyl）glucoside 2 and physicon-8-β-D-（6＇-O-acetyl）glucoside 3, were isolated from the roots of Polygonum cillinerve and their structures were established by spectroscopic methods. The biological activity indicated that compound 1 had the scavenging activity on 1,1-diphenyl-2-picrylhydrazyl （DPPH） radicals （the IC50 = 8.5 μmol/L）, and compound 1-3 showed no activities against HL-60 and BCJC-823 cells by MTT method in vitro.

Long-chain alkanol-alkyl carboxylic acid-based low-viscosity hydrophobic deep eutectic solvents for one-pot extraction of anthraquinones from Rhei Radix et Rhizoma

Natural long-chain alkanol and alkyl carboxylic acid were used to prepare novel hydrophobic deep eutectic solvents(HDESs).These HDESs are liquid at room temperature and have low viscosity(<12.26 mPa·s),low polarity(lower than that of methanol,ChCl-based deep eutectic solvents and other reported HDESs),and low density(<0.928 g/mL).A simple one-pot method based on a novel HDES-water two-phase extraction system was constructed for the extraction of weak-polarity bioactive components,anthraquinones,from Rhei Radix et Rhizoma.This HDES-based new extraction method does not consume hazardous organic solvents and can obtain a total anthraquinone yield of 21.52 mg/g,which is close to that obtained by the Chinese pharmacopoeia method(21.22 mg/g)and considerably higher than those by other reported HDESs-based extraction methods(14.20-20.09 mg/g,p<0.01).The high extraction yield can be mainly attributed to the severe destruction of the RRR cell walls by the extraction system and the excellent dissolving ability of novel HDESs for anthraquinones.

The haplotype-resolved genome assembly of autotetraploid rhubarb Rheum officinale provides insights into its genome evolution and massive accumulation of anthraquinones

Rheum officinale,a member of the Polygonaceae family,is an important medicinal plant that is widely used in traditional Chinese medicine.Here,we report a 7.68-Gb chromosome-scale assembly of R.officinale with a contig N50 of 3.47 Mb,which was clustered into 44 chromosomes across four homologous groups.Comparative genomics analysis revealed that transposable elements have made a significant contribution to its genome evolution,gene copy number variation,and gene regulation and expression,particularly of genes involved in metabolite biosynthesis,stress resistance,and root development.We placed the recent autotetraploidization of R.officinale at~0.58 mya and analyzed the genomic features of its homol-ogous chromosomes.Although no dominant monoploid genomes were observed at the overall expression level,numerous allele-differentially-expressed genes were identified,mainly with different transposable element insertions in their regulatory regions,suggesting that they functionally diverged after polyploidization.Combining genomics,transcriptomics,and metabolomics,we explored the contributions of gene family amplification and tetraploidization to the abundant anthraquinone production of R.officinale,as well as gene expression patterns and differences in anthraquinone content among tissues.Our report of-fers unprecedented genomic resources for fundamental research on the autopolyploid herb R.officinale and guidance for polyploid breeding of herbs.

Phenanthrenes,anthraquinones,and phenolic constituents from Sinomenium acutum

A phytochemical investigation on the stems and rhizomes of Sinomenium acutum led to the isolation of 19 compounds, including three phenanthrenes, six anthraquinones, and ten phenolic derivatives. The structures of the isolated compounds were elucidated by analysis of the MS and NMR spectroscopic data and comparison with the literature. Compounds 1 and 2 are two new natural products, and their 1H and 13C NMR spectral data were fully assigned for the first time, with the help of2D NMR. All of the isolates were obtained from genus Sinomenium for the first time and the phenanthrene and anthraquinone are the structure type first reported from this genus plants.

Simultaneous determination of five anthraquinones in a Chinese traditional preparation by RP-HPLC using an improved extraction procedure

OBJECTIVE： The stable quality of Chinese herbal medicines is a critical factor for their reliable clinical efficiency. An improved liquid-liquid extraction procedure and a liquid chromatographic method were developed to simultaneously analyze five anthraquinones （aloe-emodin, rhein, emodin, chrysophanol and physcion） in a Chinese traditional hospital preparation, Fuyankang mixture, in order to quantitatively control its quality in a more effective way. METHODS： A more economical and repeatable extraction procedure based on conventional liquid-liquid extraction technique was developed and used to extract five marker components in Fuyankang mixture. These anthraquinones were separated in less than 20 min on a C18 column with methanol and 0.1% phosphoric acid （88：12, v/v） as mobile phase. The method was validated for specificity, precision, spiked recovery and stability. RESULTS： Compared to conventional liquid-liquid extraction, the improved liquid-liquid extraction was found to be more effective for simultaneous extraction of anthraquinones from an aqueous Chinese herbal preparation, especially for hydrophobic compounds. The improved extraction method was successfully applied to determine the content of five marker components in Fuyankang mixture by the means of reverse phase high-performance liquid chromatography. CONCLUSION： The improved extraction procedure may be suitable for routine quality control of Fuyankanq mixture and other traditional preparations at city-level hospitals in China.

In vitro study of the nephrotoxicity of total Dahuang(Radix Et Rhizoma Rhei Palmati) anthraquinones and emodin in monolayer human proximal tubular epithelial cells cultured in a transwell chamber

OBJECTIVE: To examine changes in the morphology and physiological functions of human proximal tubular epithelial cells (HK-2 cells) caused by total Dahuang (Radix Et Rhizoma Rhei Palmati) anthraquinones (TDA) and emodin. METHODS: HK-2 cells were cultured on polycarbonate (PCF) membranes to form a complete monolayer of cells. A fluorescein isothiocyanate- dextran (FITC) permeability assay was conducted and secretion of γ-glutamyltranspeptidase (GGT), lactate dehydrogenase (LDH), N-acetyl-β-D-glucosaminidase (NAG) and kidney injury molecule 1 (KIM-1) was examined. The reabsorption of glucose and the excretion of para-aminohippuric acid (PAH) by HK-2 cells were also examined. The morphology of HK-2 cells was observed using optical microscopy and scanning electron microscopy. The cytoskeleton of HK-2 cells was observed under a fluorescence microscope. RESULTS: Compared with the results for the dimethyl sulfoxide group, treatment of cells with TDA and emodin showed statistically significant differences in the FITC leakage rate, the apical / basolateral ratio of LDH and GGT, and the secretion of GGT, LDH, NAG and KIM-1. At 64 μg/mL, TDA markedly inhibited blood glucose reabsorption and remarkably suppressed PAH excretion by HK-2 cells. Both TDA and emodin caused various degrees of damage to the morphology and cytoskeleton of HK-2 cells with the degree of damage correlating positively with the dosage of the tested substances.CONCLUSION: Both TDA and emodin caused damage to human renal proximal tubular epithelial cells at certain dosages. At the same dosage, TDA caused more severe damage than emodin to the HK-2 cells.

Antioxidant xanthones and anthraquinones isolated from a marine-derived fungus Aspergillus versicolor

Chemical examination of an EtOAc extract of cultured Aspergillus versicolor fungus from deep-sea sediments resulted in the isolation of four xanthones, eight anthraquinones and five alkaloids, including a new xanthone, oxisterigmatocystin D （1） and a new alkaloid, aspergillusine A （13）. High resolution electron impact mass spectrometry （HR-EI-MS）, FT-IR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds, and the absolute configuration of compound 1 was established by its NMR features and coupling constant. Furthermore, the biosynthesis pathway of these xanthones and anthraquinones were deduced, and their antioxidant activity and cytotoxicity in human cancer cell lines （HTC-8, Bel-7420, BGC-823, A549, and A2780） were evaluated. The trolox equivalent antioxidant capacity （TEAC） assay indicated most of the xanthones and anthraquinones possessing moderate antioxidant activities. The Nrf2-dependent luciferase reporter gene assay revealed that compounds 6, 7, 9, and 12 potentially activated the expression of Nrf2-regulated gene. In addition, compounds 5 and 11 showed weak cytotoxicity on A549 with the ICs0 values of 25.97 and 25.60 gmol·L^-1, respectively.

Distribution and pharmacokinetics of five Rhubarb anthraquinones in rabbits and rats

The main active components of Rhubarb are anthraquinones（AQs）, most of which are glycosides and others are free. The concentrations of AQs derivatives（rhein, aloe-emodin, emodin, chrysophanol and physcion） in plasma and homogenate were assayed with a high performance liquid chromatography（HPLC） method. The pharmacokinetic parameters and distribution of Rhubarb AQs in rabbits or rats were studied after administration of different formulas. Elimination of AQs was fit to a two-compartment model in rats and rabbits. There were no significant difference in the main pharmacokinetic parameters between rhein and AQs in rats. AQs were distributed progressively in the kidney, liver, blood, and heart. The AQs were mainly composed of rhein in vivo and was excreted by the kidney. For formulas that contained Rhubarb, rhein could be used as a probe for in vivo pharmacokinetic studies.

Simultaneous Determination of 10 Anthraquinones in Rhubarb Based on HPLC-Q-HR/MS

Objective To develop a simple, sensitive, and precise method for simultaneous determination of 10 anthraquinones in Rhubarb. Methods HPLC-Q-HR/MS was employed for simultaneous quantification of free anthraquinones（aloe-emodin, emodin, chrysophanol, physcion, and rhein） and their glycosides. Chromatographic analysis was performed on an XBridge^（TM） C_（18） column（2.1 mm × 150 mm, 5 μm） with mobile phases consisting of 3 mmol/L ammonium acetate（A） and methanol（B） at a flow rate of 0.3 mL/min. Results All calibration curves exhibited good linear relationship（R^2 〉 0.999）. The limits of detection（LOD） and quantification（LOQ） were in the range of0.39-2.97 ng/mL and 0.56-8.90 ng/mL, respectively. The overall intra-and inter-day precisions of analytes presented as relative standard deviations（RSDs） were less than 2.79%. Relative recoveries varied between 97.83% and 104.28%. The validated method was applied to assess the quality of Rhubarb collected from different regions of China. Results showed that chrysophanol and rhein-8-O-β-D-glucoside was the largest portion of free anthraquinones and anthraquinone glycosides in Rhubarb, respectively. The total content of anthraquinones was higher in Rhubarbs from Sichuan, Qinghai, Yunnan, and Gansu provinces than that in those from Shandong and Henan provinces, while no significant variability existed in different regions of the same province.Conclusion HPLC-Q-HR/MS method is accurate and reliable for simultaneous quantification of above free anthraquinones and their glycosides in Rhubarb and can be applied to standardize the quality of Rhubarb and its quality control in different regions.

Inhibition of human cytochrome CYP1B1 by anthraquinone compounds,chrysophanol and physcion

The in vitro inhibitory effects of chrysophanol and physcion on CYP1B1 were explored,utilizing ethoxyresorufin as the substrate.The inhibition kinetics of CYP1B1 by these compounds were assessed with escalating doses of ethoxyresorufin.Both chrysophanol(IC_(50)(0.47±0.01)μmol·L^(-1))and physcion(IC_(50)(0.35±0.02)μmol·L^(-1))significantly reduce the catalytic efficiency of CYP1B1.The V_(max)and K_(m)values are determined to be(51.9912±10.0547)pmol·μg^(-1)(protein)·min^(-1) and(0.9663±0.2987)nmol·L^(-1)for chrysophanol,and(45.4227±1.9978)pmol·μg^(-1)(protein)·min^(-1) and(0.4367±0.0386)nmol·L^(-1)for physcion,respectively.Kinetic analysis reveals that chrysophanol and physcion exert mixed inhibitory effects on CYP1B1.This mixed inhibition is primarily characterized by the compounds’ability to competitively bind to the active sites of CYP1B1,as well as potentially through non-competitive mechanisms,thereby reducing the enzyme’s catalytic efficiency.Molecular docking studies are conducted to elucidate the interaction between anthraquinone derivatives and CYP1B1,indicating that these compounds may inhibit CYP1B1 activity by binding to their active sites.The demonstrated capacity of chrysophanol and physcion to inhibit CYP1B1 enzymatic function unveils a potential anticancer mechanism,advancing our comprehension of how the structure of anthraquinone derivatives correlates with CYP1B1 inhibition and paving the way for developing innovative cancer treatments.

A Quantitative Method for Simultaneous Determination of Four Anthraquinones with One Marker in Rhei Radix et Rhizoma

Objective To develop a quantitative method for simultaneously determining multi-components in Rhei Radix et Rhizoma using one chemical reference substance.Methods The contents of multi-components were calculated by the UV relative correction factors(RCFs)of chrysophanol,physcion,and rhein to emodin.Results The values of RCFs at 274 nm for rhein,chrysophanol,and physcion to emodin were 0.712,0.674,and 1.051.The calibration curves were linear over the ranges of 0.02-4.08,0.02-4.12,0.07-12.92,and 0.02-3.68μg/mL for rhein,emodin, chrysophanol,and physcion,respectively.The contents of emodin in 18 samples were determined by the external standard method,and the contents of the other three anthraquinone aglycones were calculated according to their RCFs. Conclusion No significant difference is found in comparison with the classical method,indicating that the RCFs have high reliability within their linear ranges and could be used in quality control of Rhei Radix et Rhizoma.The quantitative analysis of multi-component with a single marker is especially suitable for herbal medicines containing unstable or hard to be purified components as quality control markers.

Natural and unnatural anthraquinones isolated from the ethanol extract of the roots of Knoxia valerianoides

Eight new 9,10-anthraquinones(1-8)including three acetonide derivatives of 3-hydroxy-2-hydroxymethyl-9,10-anthraquinones(68)were isolated from an ethanol extract of the roots of Knoxia valeriamoides.On the basis of chemical transformation reactions of the co-occurring 14 and 15 combined with HPLC-DAD-ESI-MS analysis of the extracts,the previously and newly isolated 2-methoxymethy-and 2-ethoxymethyl-9,10-anthraquinones(4,5,and 9-13),as well as the 3-hydroxy-2-hydroxymethyl-9,10-anthraquinone acetonide derivatives(68),were shown to be solvolytic artifacts.In the in vitro assays,compound 4 was active to protect hepatocyte(WB-F344)damage.

Antimicrobial Properties and Toxicity of Anthraquinones by Microcalorimetric Bioassay

The growth therrnogenic curves of Staphylococcus aureus and Tetrahymena thermophila affected by 1,8-dihydroxyanthraquinone, emodin and rhein were determined quantitatively by microcalorimetry. The inhibitory effects of the three anthraquinones （AQ） on S. aureus revealed that the sequence of antimicrobial activity of those was rhein〉emodin〉 1,8-dihydroxyanthraquinone. The toxicity of the three AQ on T. thermophila indicated that all the tested AQ were toxic to the tested protozoa and the hydroxyl and carboxyl substituted at different position of anthraquinone ring resulted in the enhancement of toxicity.

Simultaneous Determination of Four Anthraquinones in Polygoni Multiflori Radix with Single Reference Standard by High Performance Liquid Chromatography

Objective: To establish a rapid, accurate and reliable analytical method for the simultaneous determination of four major anthraquinones in Polygoni Multiflori Radix(PMR) using single reference standard.Methods: The four components including emodin-8-O-β-D-(EMG), physcion-8-O-β-D-glucoside, emodin and physcion were separated on an ODS C18 column within 13 min and detected at 280 nm. Emodin was selected as the reference standard, and the response factor for each analyte with respect to emodin were calculated. Robustness were also tested including different columns, equipments, temperatures, detection wavelengths, and other chromatographic conditions which might influence stability of response factors.Results: The method was validated in terms of linearity(r^2> 0.9995), LOQs(0.820–3.05 ng/m L), LODs(0.180–0.920 ng/m L), precision,accuracy(95.8–103.6%, RSD < 2.80%) and stability. A total of 40 batches of PMR were analyzed and the results were found to have no statistically significant differences compared with those obtained using the external standard method.Conclusion: This work provided a single standard to determine multi-components method for quantitation of four anthraquinones in PMR,which could be applied in the quality control of this herbal drug.