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.

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.

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.

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

Chemical examination of an EtO Ac 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 IC50 values of 25.97 and 25.60 μmol×L^(–1), respectively.

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.

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.

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.

Fabrication of hydrophobic Pd/Al_(2)O_(3)-phosphoric acid via P-O-Al bond for liquid hydrogenation reaction

Alumina(Al_(2)O_(3))is widely used in the chemical industry as the catalyst and support due to its high specific surface area,abundant pore size distribution and chemical stability.However,the occurrence of hydration in water environment,result in outstanding decrease in specific surface area and collapse of pore structure.In this work,dodecyl phosphoric acid(PA)is used to modify the surface of Al_(2)O_(3)to obtain a series of hydrophobic material(Al_(2)O_(3)-PA).Based on XPS and NMR analysis,PA is chemically bonded on Al_(2)O_(3)to form PAOAAl bond.Furthermore,BET and WCA results display that Al_(2)O_(3)-1PA exhibits excellent the hydrophobicity and hydrothermal stability while maintains the pore structure.Take it as the substrate to support the Pd nanoparticles,the as-prepared Pd/Al_(2)O_(3)-PA shows the superior catalytic performance in the hydrogenation of phenol and anthraquinone relative to Pd/Al_(2)O_(3),indicating the accessibility of Pd sites after PA modification.Especially,the significantly enhanced stability is also obtained in four cycles for aqueous phenol hydrogenation.This can be ascribed that the PA modification inhibits the aggregation of Pd nanoparticles and the products adhesion in the reaction process.The extension of PA coatings to monolithic catalysts could expand their current capabilities in industrial applications and warrants ongoing investigation.

Valorization of Aloe barbadensis Miller. (Aloe vera) Processing Waste

Aloe vera plant is known worldwide for its medicinal properties and application in gel-based products such as shampoo,soap,and sunscreen.However,the demand for these gel-based products has led to a surplus production of Aloe vera processing waste.An Aloe vera gel processing facility could generate up to 4000 kg of Aloe vera waste per month.Currently the Aloe vera waste is being disposed to the landfill or used as fertilizer.A sustainable management system for the Aloe vera processing waste should be considered,due to the negative societal and environmental impacts of the currents waste disposal methods.Therefore,this review focuses on various approaches that can be used to valorize Aloe vera waste into value-added products,such as animal and aquaculture feeds,biosorbents,biofuel and natural polymers.Researchers have reported Aloe vera waste for environmental applications biosorbents used for wastewater treatment of various pollutants.Several studies have also reported on the valorization of Aloe vera waste for production of biofuels such as bioethanol,mixed alcohol fuels,biogas and syngas.Aloe vera waste could also be valorized through isolation and synthesis of natural polymers for application in wound dressing,tissue engineering and drug delivery systems.Aloe vera waste valorization was also reviewed through extraction of value-added bioactive compounds such as aloe-emodin,aloin and aloeresin.These value-added bioactive compounds have various applications in the cosmetics(non-steroidal anti-inflammatory,tyrosinase inhibitors)and pharmaceutical(anticancer agent and COVID 19 inhibitors)industry.

Animal models of cathartic colon

The incidence of cathartic colon has been increasing,but satisfactory treatments are still lacking.In order to study the pathological mechanisms of the disorder and identify effective treatment methods,researchers have established different animal models of cathartic colon.This minireview briefly summarizes several common cathartic colon animal models,induced with anthraquinone laxatives such as rhubarb,total anthraquinone,rhein,and emodin,or induced with diphenylmethane laxatives such as phenolphthalein.The advantages and limitations of these models are evaluated and analyzed.We hope that this review will facilitate the selection of suitable models and improve relevant modeling methods.We anticipate the development of more convenient and stable models that can reflect the characteristics of cathartic colon in humans,and serve as useful tools for further studies.

Bidirectional solid fermentation using Trametes robiniophila Murr. For enhancing efficacy and reducing toxicity of rhubarb (Rheum palmatum L.)

Objective:To investigate the potential of bidirectional solid fermentation of rhubarb (Rheum palmatum L.) for reducing its toxicity and enhancing its medicinal efficacy.Methods:The fungus Trametes robiniophila Murr.was inoculated into rhubarb.The chemical ingredients as well as antioxidant,antibacterial,and anticancer activities of fermented and unfermented rhubarb extracts were then determined.Results:After fermentation,levels of anthraquinone glycosides (purgative ingredients) decreased significantly,while the level of anthraquinone aglycone increased.The level of gallic acid was also reduced after fermentation.Ethanol extract of rhubarb (0.8 mg/mL) exhibited DPPH-scavenging activity of 7.6% ± 0.8% while the blank control (0.8 mg/mL rhubarb)showed 31.3% ± 2.0% activity.Antibacterial activities in fermented samples were found to be enhanced compared with unfermented samples and anticancer activity was evident at concentrations of 2000 and 5000 μg/mL.Conclusion:Bidirectional solid fermentation appears to be an effective processing method that can be used to improve the efficacy and reduce the toxicity of rhubarb.

Effect of EuCl_3 on Hairy Root Growth of Cassia Obtusifolia and Production of Its Active Principle

Treated with extremely low EuCl 3 (0 001, 0 01, 1 0 mg·L -1 ) in MS medium, the hairy root growth of Cassia obtusifolia was inhibited. The inhibition was strongest at the treatment with 0 001 mg·L -1 EuCl 3, and the dry weight of hairy roots was 22% lower than that of control. Treated with rather low EuCl 3 (10 mg·L -1 ) in Murashige and Skoog(MS) medium, the hairy root growth was enhanced, and the dry weight of hairy roots was 27% higher than that of control. In the each treatment with 0 001 to 1 0 mg·L -1 EuCl 3 in MS medium, the total content of six free anthraquinones was lower than that of control. While treated with 10 mg·L -1 EuCl 3, the total content of six free anthraquinones was 26% higher than that of control, 97% higher than the treatment of 1 0 g·L -1 EuCl 3. Treatment with 10 mg·L -1 EuCl 3 in MS medium enhances the growth of hairy root of Cassia obtusifolia and improves the total content and production of six free anthraquinones in them.

The genus Rumex(Polygonaceae):an ethnobotanical,phytochemical and pharmacological review

Rumex L.,a genus in Polygonaceae family with about 200 species,is growing widely around the world.Some Rumex species,called"sorrel"or"dock",have been used as food application and treatment of skin diseases and hemostasis after trauma by the local people of its growing areas for centuries.To date,29 Rumex species have been studied to contain about 268 substances,including anthraquinones,flavonoids,naphthalenes,stilbenes,diterpene alkaloids,terpenes,lignans,and tannins.Crude extract of Rumex spp.and the pure isolates displayed various bioactivities,such as antibacterial,anti-inflammatory,antitumor,antioxidant,cardiovascular protection and antiaging activities.Rumex species have important potential to become a clinical medicinal source in future.This review covers research articles from 1900 to 2022,fetched from SciFinder,Web of Science,ResearchGate,CNKI and Google Scholar,using“Rumex”as a search term("all fields")with no specific time frame set for the search.Thirty-five Rumex species were selected and summarized on their geographical distribution,edible parts,traditional uses,chemical research and pharmacological properties.

Identification of the multiple bioactive derivatives and their endogenous molecular targets that may mediate the laxative effect of rhubarb in rats

Objective:To determine the mechanism of the laxative effect of rhubarb(Rheum tanguticum Maxim.ex Balf.)in rats using a combined bioinformatic and in vivo approach.Methods:Substances derived from rhubarb that are present in the colorectum were identified using high-performance liquid chromatography,coupled with linear ion-trap quadrupole Orbitrap highresolution mass spectrometry.The targets with a potential laxative effect were identified from databases and the literature,then used with rhubarb-derived substances in molecular docking modeling.The expression of candidate endogenous target molecules that bound specific components of rhubarb was then measured in constipated rats that had or had not been administered rhubarb by western blotting.Finally,potentially bioactive compounds were traced back to their prototype components.Results:We identified 17 anthraquinones and 21 anthrones derived from rhubarb in the colorectum of rats.G-scoring identified three potential mediators of the laxative effect:c-kit,5-hydroxytryptamine receptor 4(5-HT4),and aquaporin-3(AQP3).In addition,10 rhubarb-derived components(aloeemodin,emodin,rhein,chrysophanol,physcion,sennoside A,sennoside C,physcionanthrone,aloeemodinanthrone,and rheinanthrone),which have strong binding affinities for more than one of the three potential targets,were selected as likely active compounds.Rhubarb extract increased the expression of c-kit and 5-HT4,and reduced the expression of AQP3 in the colon of constipated rats,which might mediate its laxative effect.We also found that a single prototype component may be metabolized into several active metabolites,and a single active ingredient can also be generated from various prototype compounds.Conclusion:The present study demonstrates that various anthraquinones and anthrones present in rhubarb may be metabolized to form bioactive compounds that have additive or synergistic effects to promote defecation via c-kit,5-HT4 and/or AQP3.