Effect of emodin on small intestinal peristalsis of mice and relevant mechanism

Metabolic profile and dynamic characteristic of rhubarb during the vitro biotransformation by human gut microbiota

Rhubarb is a popular food in the world with laxative effects and steamed pieces of rhubarb (SP) have been widely applied to treatment of constipation in China due to its safety and effectiveness. In the study, metabolism in vitro was conducted to study influence of gut microbiota between raw pieces of rhubarb (RP) and SP. The results showed obvious classifications in metabolic profile between RP and SP were revealed by chemometric analysis, and prompted gut microbiota affected metabolism of rhubarb. Furthermore, 16 characteristic components were identified to distinguish the differences in metabolism. Finally, quantitative analysis of 14 components were verified the regulation of gut microbiota on rhubarb and discovered concentration of components affected the rate of metabolism. The study indicated regulation by gut microbiota could be probably responsible for differences of laxative effects between RP and SP, providing new perspective for exploring mechanisms of effectiveness in clinical application for SP.

Emodin - A natural anthraquinone derivative with diverse pharmacological activities

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural anthraquinone derivative that is present in numerous globally renowned herbal medicines. It is recognised as a protein tyrosine kinase inhibitor and as an anticancer drug, active against various tumour cells, including lung, breast, liver, and ovarian cancer cells. Recently, its role in combination chemotherapy with various allopathic medicines, to minimize their toxicity and to enhance their efficacy, has been studied. The use of emodin in these therapies is gaining popularity, due to fewer associated side effects compared with standard anticancer drugs. Emodin has a broad therapeutic window, and in addition to its antineoplastic activity, it displays anti-ulcer, anti-inflammatory, hepatoprotective, neuroprotective, antimicrobial, muscle relaxant, immunosuppressive and antifibrotic activities, in both in vitro and in vivo models. Although reviews on the anticancer activity of emodin have been published, none coherently unite all the pharmacological properties of emodin, particularly the anti-oxidant, antimicrobial, antidiabetic, immunosuppressive and hepatoprotective activities of the compound. Hence, in this review, all of the available data regarding the pharmacological properties of emodin are explored, with particular emphasis on the modes of action of the molecule. In addition, the manuscript details the occurrence, biosynthesis and chemical synthesis of the compound, as well as its toxic effects on biotic systems.

Integrated assessment of medicinal rhubarb by combination of delayed luminescence and HPLC fingerprint with emphasized on bioactivities based quality control

Background

To promote herbal medicine depends largely on its quality. Chromatographic fingerprint is a frequent approach for quality assessment of herbs however with challenges on robust and reproducibility. To develop rapid, cheap and comprehensive measurements as complementary tools for herbal quality control are still urgently needed. Moreover, biological activities are essential for herbal quality, and should be taken into consideration with emphasized in quality control.

Methods

In this research, HPLC fingerprint and delayed luminescence (DL, a rapid and systematic tool) were used to measure the rhubarb samples of multiple species. Statistics were explored to classify these rhubarb samples using data obtained from two analytic methods. In addition, DL properties were linked to specific chemical components which may reflect bioactivities of rhubarb using Spearman's rank correlation. Moreover, mice model was used to evaluate the cathartic effect between rhubarb samples stratifying by two analytic methods.

Results

We found that there was no significant difference of chemical fingerprints and DL signals among the different species of medicinal rhubarb. However, our results show a high similarity between HPLC fingerprint analysis and DL measurements in classification of these rhubarb samples into two sub-groups. In addition, the two sub-groups of rhubarb samples that may have different cathartic activities.

Conclusion

This approach provides new leads for development of herbal quality assessment based on bioactivity. In conclusion, integrated assessment by measuring HPLC fingerprint and DL with emphasized on bioactivity may provide novel strategy for herbal quality control.

Gastrointestinal Motility and Improvement Efficacy of Shenhuang Plaster Application on Shenque: Identification, Evaluation, and Mechanism

Constipation, a gastrointestinal function disorder, is one of the side effects of paclitaxel (PTX) chemotherapy. Shenhuang plaster (SHP) application on the Shenque acupoint promotes gut motility in clinical settings. In this study, we elucidated the ingredients in SHP and evaluated its effects on PTX-induced constipation using a tumour-bearing mouse model. SHP was prepared using the traditional Chinese plaster preparation method. The ingredients were analysed using UPLC-MS/MS and identified via screening in a standard drug database. The gastrointestinal transit was evaluated by the movement of a fluorescein-labelled dextran in the gastrointestinal tract. A histological study of the mucosa was carried out after haematoxylin and eosin staining. mRNA expression was assessed using real-time RT-PCR, and the foetal microbiota composition was elucidated through 16 s rDNA sequencing and BLAST analysis. Our results indicate that the application of SHP attenuated weight gain inhibition by PTX; however, no inhibitory effect was observed on tumour growth. PTX-induced sluggish intestine, villus, and mucosal base layer damage were significantly improved following the application of SHP. Further, SHP enhanced the stimulation efficiency of PTX on TLR4 and its downstream cytokines, as well as on IL-1β in intestinal cells. SHP combined with PTX reshaped the microbiota, which showed beneficial effects on health. Hence, these results provide evidence that SHP alleviates PTX-induced constipation and intestinal morphological damage but augments the effects of PTX on the expression of cytokines in the TLR4 pathway and IL-1β. Therefore, we propose that SHP stimulates the host immune response to eradicate cancer cells.

UPLC-ESI-MS/MS-Based Widely Targeted Metabolomics Analysis of Wood Metabolites in Teak (Tectona grandis)

The properties of teak wood, such as natural durability and beautiful color, are closely associated with wood extractives. In order to further understand the performance differences between teak heartwood and sapwood, we analyzed the chemical components of extractives from 12 wood samples using an ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS)-based metabolomics approach. In total, 691 metabolites were identified, and these were classified into 17 different categories. Clustering analysis and principal component analysis of metabolites showed that heartwood samples could be clearly separated from sapwood samples. Differential metabolite analysis revealed that the levels of primary metabolites, including carbohydrates, amino acids, lipids, and nucleotides, were significantly lower in the heartwood than in the sapwood. Conversely, many secondary metabolites, including flavonoids, phenylpropanoids, and quinones, had higher levels in the heartwood than in the sapwood. In addition, we detected 16 specifically expressed secondary metabolites in the heartwood, the presence of which may correlate with the durability and color of teak heartwood. Our study improves the understanding of differential metabolites between sapwood and heartwood of teak, and provides a reference for the study of heartwood formation.

Emodin Rescues Intrahepatic Cholestasis via Stimulating FXR/BSEP Pathway in Promoting the Canalicular Export of Accumulated Bile

Aim

Bile salt export pump (BSEP) have been confirmed to play an important role for bile acid canalicular export in the treatment of cholestasis. In this study, we investigated the stimulatory effect of emodin on BSEP signaling pathway in cholestasis.

Methods

Cell and animal experiments were given different concentrations of emodin. The BSEP upstream molecule farnesoid X receptor was down-regulated by small interfering RNA (siRNA) technology or guggulsterones and up-regulated by lentivirus or GW4064. Real-time PCR and Western blotting was employed to detect the mRNA and protein levels of BSEP in LO2 cell, rat primary hepatocytes and liver tissue. Immunohistochemistry (IHC) was used to examine the expression of BSEP in liver tissues. Rat liver function and pathological changes of liver tissue were performed by biochemical test and hematoxylin and eosin (HE) staining.

Results

Emodin could increase the mRNA and protein expression of BSEP and FXR. When down-regulating farnesoid X receptor expression with the siRNA or inhibitor guggulsterones, and up-regulating farnesoid X receptor expression with the lentivirus or agonist GW4064, emodin could increase the mRNA level of BSEP and FXR and the protein level of BSEP, FXR1, and FXR2. Emodin also had a notable effect on rat primary hepatocytes experiment, rat pathological manifestation, BSEP, FXR1, and FXR2 positive staining in liver tissues and the test of liver function.

Conclusion

Emodin has a protective effect and a rescue activity on cholestasis via stimulating FXR/BSEP pathways in promoting the canalicular export of accumulated bile.

Effect of emodin on mobility signal transduction system of gallbladder smooth muscle in Guinea pig with cholelithiasis

OBJECTIVE

To study the effect of emodin on protein and gene expressions of the massagers in mobility signal transduction system of cholecyst smooth muscle cells in guinea pig with cholesterol calculus.

METHODS

The guinea pigs were randomly divided into 4 groups, such as control group, gall-stone (GS) group, emodin group and ursodeoxycholic acid (UA) group. Cholesterol calculus models were induced in guinea pigs of GS, emodin and UA groups by lithogenic diet, while emodin or UA were given to the corresponding group for 7 weeks. The histomorphological and ultrastructure change of gallbladder were detected by microscope and electron microscope, the content of plasma cholecystokinin (CCK) and [Ca²⁺]_i were analyzed successively by radioimmunoassay and flow cytometry. The protein and mRNA of Gsα, Giα and Cap in cholecyst cells were determined by western blotting and real time polymerase chain reaction (RT-PCR).

RESULTS

Emodin or UA can relieve pathogenic changes in epithelial cells and muscle cells in gallbladder of guinea pig with cholesterol calculus by microscope and transmission electron microscope. In the cholecyst cells of GS group, CCK levels in plasma and [Ca²⁺]_i decreased, the protein and mRNA of GS were down-regulated, the protein and mRNA of Gi and Cap were up-regulated. Emodin significantly decreased the formative rate of gallstone, improved the pathogenic change in epithelial cells and muscle cells, increased CCK levels in plasma and [Ca²⁺]_i in cholecyst cells, enhanced the protein and mRNA of Gs in cholecyst cells, reduced the protein and mRNA of Gi and Cap in cholecyst cells in guinea pig with cholesterol calculus.

CONCLUSION

The dysfunction of gallbladder contraction gives rise to the disorders of mobility signal transduction system in cholecyst smooth muscle cells, including low content of plasma CCK and [Ca²⁺]_i in cholecyst cells, abnormal protein and mRNA of Gs, Gi and Cap. Emodin can enhance the contractibility of gallbladder and alleviate cholestasis by regulating plasma CCK levels, [Ca²⁺]_i in cholecyst cells and the protein and mRNA of Gs, Gi and Cap.

Forced Degradation Studies of Aloe Emodin and Emodin by HPTLC

Anthraquinones are natural phenolic compounds, which are reported to act as anti-aging, anti-inflammatory, antioxidant, anti-cancer, laxative and antitumor agents. They are abudant in plants like candle bush, aloes, cascara bark and rhubarb. The present work was to observe the effect of different forced degradation conditions by high-performance thin layer chromatography on potential markers i.e. aloe emodin and emodin. Both aloe emodin and emodin were subjected to various forced degradation studies such as oxidation, acid and alkaline hydrolysis, photolysis, hydrolytic and thermal degradation. Aloe emodin, was more susceptible to acid hydrolysis and degradation was found to a lesser extent under thermal degradation whereas significant degradation was observed under acid hydrolysis, lesser extent was observed under alkali hydrolysis for emodin. Forced degradation studies on aloe emodin and emodin gives information about its storage and intrinsic stability conditions considering the advanced pharmaceutical aspects of formulation.

Rhubarb to Facilitate Placement of Nasojejunal Feeding Tubes in Patients in the Intensive Care Unit

BACKGROUND

Prokinetic agents are sometimes needed to aid in the placement of nasojejunal feeding tubes in patients at risk of malnutrition. The objective of the present study was to evaluate the feasibility of rhubarb as a new prokinetic agent to replace metoclopramide and erythromycin in the placement of nasojejunal feeding tubes.

MATERIALS AND METHODS

Ninety-four patients who required jejunal feeding tube insertion were included. They were divided into rhubarb (n = 34), metoclopramide (n = 31), and erythromycin groups (n = 29), depending on the use of rhubarb, metoclopramide, and erythromycin as the prokinetic agent. The jejunal feeding tube insertions were performed at the bedside. An abdominal x-ray was taken as the gold standard to determine the position of the tube. Cases in which insertion failed in either group were subjected to a second insertion attempt using rhubarb as the prokinetic agent.

RESULTS

The success rates in the rhubarb, metoclopramide, and erythromycin groups were 91.2%, 87.1%, and 89.7%, respectively. The difference in the success rates was not statistically significant (P = .916). The insertion times in the rhubarb, metoclopramide, and erythromycin groups were 16.0 ± 1.9 minutes, 18.0 ± 1.9 minutes, and 18.8 ± 2.2 minutes, respectively. The insertion time in the rhubarb group was significantly shorter than those in metoclopramide and erythromycin groups (P < .001). No side effects were noted in the rhubarb group.

CONCLUSIONS

Rhubarb could serve as an effective prokinetic agent to promote the insertion of nasojejunal feeding tubes.

Da-cheng-qi decoction, a traditional Chinese herbal formula, for intestinal obstruction: systematic review and meta-analysis

BACKGROUND

This study was aimed at determining the effects and safety of Da-Cheng-Qi decoction (DCQD) or DCQD combined with conservative therapy in patients with intestinal obstruction.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane Controlled Trials Register, and several other databases were searched. Randomised controlled trials (RCTs) of DCQD or DCQD plus conservative therapy in patients with intestinal obstruction were eligible. Therapeutic effect was estimated by the improvement of clinical manifestations and diagnostic imaging; dichotomous/ordinal data assessment of overall response to therapy, adverse effects; or continuous variable were identified, including time to first bowel movement, time to first flatus, length of hospital stay.

RESULTS

Sixty eligible RCTs including 6,095 patients were identified. Response rate: (1) DCQD versus conservative therapy (6 RCTs, 361 patients, RR of respond =1.13; 95% CI 0.97 to 1.31). (2) DCQD plus conservative therapy versus conservative therapy (48 RCTs, 4,916 patients, RR of respond =1.25 which favoured DCQD plus conservative therapy; 95% CI 1.20 to 1.30). Treatment effect remained similar when RCTs at high risk of bias were excluded. Time to first flatus postoperatively: (1) DCQD versus conservative therapy (2 RCTs, 240 patients, SMD=-3.65; 95% CI -8.17 to 0.87). (2) DCQD plus conservative therapy versus conservative therapy (11 RCTs, 1,040 patients, SMD=-2.09 which favoured DCQD plus conservative therapy; 95% CI -3.04 to -1.15).

CONCLUSION

DCQD combined with conservative therapy may increase the success rate of conservative therapy for intestinal obstruction significantly and can shorten the duration of postoperative ileus in patients undergoing abdominal surgery compared with conservative therapy alone.

Purgative components in rhubarbs: adrenergic receptor inhibitors linked with glucose carriers

Rhubarbs and their extractives have been used as cathartic for many years. There have been numerous breakthroughs in the pharmacological research of the drug. However, as the key point of the mechanism, the targets of the effective components still remain unclear. In this paper, with an in vitro system of isolated intestine, we found that both the rhubarb extractives and the anthraquinone derivatives can antagonize the adrenaline effectively. Furthermore, computer based docking provided the binding model of the anthraquinone derivatives and adrenergic receptor. Then, based on the results of the small intestinal promotion and purgative effect experiments in vivo, we built an "inhibitor-carrier" hypothesis to elucidate the mechanism of rhubarb. This work provided key massages for the pharmacological research of rhubarb, such a common and active medicinal plant, and might be of help for the development of new purgative drugs.

Emodin induces cytotoxic effect in human breast carcinoma MCF-7 cell through modulating the expression of apoptosis-related genes

CONTEXT

The poor prognostic outcome of breast cancer is largely due to its resistance to cancer therapies. Development of therapeutic agents that can inhibit growth and induce apoptosis in breast cancer cells can help solve the problem. Emodin is an active anthraquinone that has been reported to have diverse biological effects.

OBJECTIVE

In this study, the anticancer effects of emodin on growth inhibition, apoptosis induction and the expression of apoptosis-related genes in MCF-7 cells were investigated.

MATERIALS AND METHODS

Growth inhibition induced by emodin was investigated by the MTS assay and the colony formation assay; while emodin-induced apoptosis was determined by the COMET assay and DNA fragmentation detection. Emodin (35 μM)-induced alterations in the expression of apoptotic-related genes were detected by using real-time PCR.

RESULTS

Emodin had significant growth inhibitory effects on MCF-7 cells with IC₅₀ = 7.22 µg/ml (∼30 μM). It also exerted a concentration-dependant inhibitory effect on the colony-forming ability of MCF-7 cells with IC₅₀ = 7.60 µg/ml (∼30 µM). Hallmarks of apoptosis, such as single-strand DNA breakage and DNA fragmentation, were observed in emodin-treated MCF-7 cells. The gene expression of Fas ligand (FASL) was up-regulated (p < 0.01) but those of MCL1, CCND1 and C-MYC were down-regulated (p < 0.05) in emodin-treated MCF-7 cells.

DISCUSSION AND CONCLUSION

This study indicated that emodin could induce growth inhibition and apoptosis in MCF-7 cells through the modulation of the expression of apoptosis-related genes. The growth inhibitory effects of emodin might involve both the intrinsic and the extrinsic apoptotic pathways and cell cycle arrest.

Emodin elicits cytotoxicity in human lung adenocarcinoma A549 cells through inducing apoptosis

This study investigated the mechanism of the cytotoxic effect of emodin, an active anthraquinone, on human lung adenocarcinoma A549 cells. In vitro growth inhibition and suppression on colony forming were used to evaluate the effects of emodin on A549 cells. Emodin's ability in changing the expressions of apoptosis-related genes was studied by real-time RT-PCR. Emodin could significantly inhibit the growth of A549 cells with IC50 = 16.85 μg/ml (~60 μM). It also concentration dependently inhibited the colony-forming ability of A549 cells with IC50 = 7.60 μg/ml (~30 μM). Hallmarks of apoptosis, such as single-strand DNA breakage and DNA fragmentation, were observed in A549 cells treated with emodin. Emodin (72 h) treatment could up-regulate the gene expression of FASL (p < 0.05) and down-regulate the gene expression of C-MYC (p < 0.01), but induce no significant changes in the gene expressions of MCL1, GAPDH, BAX and CCND1. These results suggest that emodin could induce growth inhibition and apoptosis in A549 cells through modifying the extrinsic apoptotic pathways and the induction of cell cycle arrest.

Analysis on clinically drug-used law for lung-intestine related diseases

OBJECTIVE

To analyze the application laws of clinical drugs by descriptive statistical method with the clinical literatures guided by "lung being connected with large intestine" used as the object.

METHODS

Retrieve publicly published clinical literatures about "lung being connected with large intestine" in recent 30 years, establish the database of clinical literature, and study on the clinically drug-used laws by descriptive statistical analytic method.

RESULTS

The common high frequent drugs used for the lung-intestine related diseases were Gualou (Ructus Trichsanthis), Dahuang (Radix et Rhizoma), Kuxingren (Semen Armeniacae Amarum), Gancao (Radix Glycyrrhizae), Houpu (Cortex Magnoliae Officinalis), Zhishi (Fructus Aurantii Immaturus). For the different clinical syndrome types, in the commonly used drugs there were different characteristics, reflecting the principle of TCM syndrome differentiation treatment.

CONCLUSION

The common high frequent drugs used for the lung-intestine related diseases are Gualou (Fructus Trichsanthis), Dahuang (Radix et Rhizoma), Kuxingren (Semen Armeniacae Amarum), Gancao (Radix Glycyrrhizae), Houpu (Cortex Magnoliae Officinalis), Zhishi (Fructus Aurantii Immaturus), which are commonly-used drugs for the lung-intestine related diseases, with differences for different syndrome types.

Characteristics of emodin on modulating the contractility of jejunal smooth muscle

Emodin is traditionally used as a laxative and is found to increase or decrease the contractility of intestinal smooth muscle in low doses and high doses, respectively. In this study, we propose that bidirectional regulation (BR) on the contractility of jejunal smooth muscle (CJSM) is inducible by emodin in the absence of control by the central nervous system. The results indicated that emodin-induced BR had the following characteristics. A stimulatory effect on CJSM was induced by emodin at 7 low contractile states, and an inhibitory effect was induced on CJSM at 7 high contractile states. Emodin-induced BR on myosin phosphorylation was also observed. BR was not observed in the presence of tetrodotoxin, suggesting that enteric nervous system is required for producing BR. The stimulatory effect of emodin on CJSM was abolished by atropine and diphenhydramine, respectively, suggesting that BR was correlated with cholinergic and histamine system while jejunal smooth muscle was at low contractile state. The inhibitory effect of emodin on CJSM was abolished by phentolamine, propranolol, and L-NG-nitroarginine (L-NNA), respectively, suggesting that BR was related to adrenergic hyperactivity and with a nitric oxide relaxing mechanism while jejunal smooth muscle was in a high contractile state. The exact mechanism, however, needs further investigation.

Development and application of high-performance liquid chromatography for the study of two new oxyprenylated anthraquinones produced by Rhamnus species

Rhamnus spp. is known to contain biologically active anthraquinone secondary metabolites but the presence of oxyprenylated ones is not reported. To this aim, a new simple, and accurate analytical method was developed to reveal chemical fingerprint of these analytes in plant extracts. Plant samples were analysed after extraction with n-hexane (first step) and methanol (second step) using a C(18) column with a mobile phase composed of 35% of water:65% of methanol (both with 1% formic acid, v/v) at 0.7 mL min⁻¹ flow rate in gradient elution mode. For quantitative analyses, selective detection was performed at 435 nm. The limit of quantification (LOQ) was 0.5 μM, with the only exception of 3-geranyloxyemodin for which the LOQ value was 5.0 μM, and external matrix-matched standard curves showed linearity up to 125 μM. The within- and between-batch precision (RSD%) values ranged from 0.2% to 12.9% while within- and between-batch trueness (bias%) values ranged from 12.2% to 12.7%. The method was applied to evaluate for the first time the presence and the quantities of oxyprenylated anthraquinones in Rhamnus spp. barks as well as the anthraquinone profile of Rhamnus pumila Turra. The proposed method could be directly applied to the selective quantification of these analytes in natural sources.

Emodin induces chloride secretion in rat distal colon through activation of mast cells and enteric neurons

BACKGROUND AND PURPOSE

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is an active component of many herb-based laxatives. However, its mechanism of action is unclear. The aim of the present study was to investigate the role of mast cells and enteric neurons in emodin-induced ion secretion in the rat colon.

EXPERIMENTAL APPROACH

Short-circuit current (I(SC)) recording was used to measure epithelial ion transport. A scanning ion-selective electrode technique was used to directly measure Cl(-) flux (J(Cl)-) across the epithelium. RIA was used to measure emodin-induced histamine release.

KEY RESULTS

Basolateral addition of emodin induced a concentration-dependent increase in I(SC) in colonic mucosa/submucosa preparations, EC(50) 75 µM. The effect of emodin was blocked by apically applied glibenclamide, a Cl(-) channel blocker, and by basolateral application of bumetanide, an inhibitor of the Na(+) -K(+) -2Cl(-) cotransporter. Emodin-evoked J(Cl)- in mucosa/submucosa preparations was measured by scanning ion-selective electrode technique, which correlated to the increase in I(SC) and was significantly suppressed by glibenclamide and bumetanide. Pretreatment with tetrodotoxin and the muscarinic receptor antagonist atropine had no effect on emodin-induced ΔI(SC) in mucosa-only preparations, but significantly reduced emodin-induced ΔI(SC) and J(Cl)- in mucosa/submucosa preparations. The COX inhibitor indomethacin, the mast cell stabilizer ketotifen and H(1) receptor antagonist pyrilamine significantly reduced emodin-induced ΔI(SC) in mucosa and mucosa/submucosa preparations. The H(2) receptor antagonist cimetidine inhibited emodin-induced ΔI(SC) and J(Cl)- only in the mucosa/submucosa preparations. Furthermore, emodin increased histamine release from the colonic mucosa/submucosa tissues.

CONCLUSIONS AND IMPLICATIONS

The results suggest that emodin-induced colonic Cl(-) secretion involves mast cell degranulation and activation of cholinergic and non-cholinergic submucosal neurons.

Comparison of three different extraction methods and HPLC determination of the anthraquinones aloe-emodine, emodine, rheine, chrysophanol and physcione in the bark of Rhamnus alpinus L. (Rhamnaceae)

INTRODUCTION

Rhamnus alpinus L. (Rhamnaceae), a traditional plants in the flora of the Abruzzo region, is known to contain active anthraquinone secondary metabolites. However, the content of anthraquinones varies among R. alpinus samples depending on collection season and site. Thus, using simple, reliable and accurate analytical methods for the determination of anthraquinones in R. alpinus extracts allows comparative study of different methods of extraction.

OBJECTIVE

After a partial validation of an HPLC method for the simultaneous determination of five anthraquinones, aloe-emodine, rheine, emodine, chrysophanol and physcione, in the bark of R. alpinus, we compared three different methods of extraction.

METHODOLOGY

Anthraquinones were extracted from the bark of R. alpinus using different techniques (methanol maceration, ultrasonic and supercritical CO(2) extraction). Separation and quantification of anthraquinones were accomplished using a reversed-phase C(18) column with the mobile phase of H(2)O-methanol (40 : 60, v/v, 1% formic acid) at a wavelength of 254 nm. The qualitative analyses were also achieved at wavelength of 435 nm.

RESULTS

All calibration curves were linear over the concentration range tested (10-200 mM) with the determination coefficients >or=0.991. The detection limits (S/N = 3) were 5 mM for each analytes. All five anthraquinones were found in the samples tested at concentrations reported in experimental data.

CONCLUSION

The described HPLC method and optimised extraction procedure are simple, accurate and selective for separation and quantification of anthraquinones in the bark of R. alpinus and allow evaluation of the best extraction procedure between the tested assays.

Molecular mechanism of emodin action: transition from laxative ingredient to an antitumor agent

Anthraquinones represent a large family of compounds having diverse biological properties. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a naturally occurring anthraquinone present in the roots and barks of numerous plants, molds, and lichens, and an active ingredient of various Chinese herbs. Earlier studies have documented mutagenic/genotoxic effects of emodin, mainly in bacterial system. Emodin, first assigned to be a specific inhibitor of the protein tyrosine kinase p65lck, has now a number of cellular targets interacting with it. Its inhibitory effect on mammalian cell cycle modulation in specific oncogene overexpressed cells formed the basis of using this compound as an anticancer agent. Identification of apoptosis as a mechanism of elimination of cells treated with cytotoxic agents initiated new studies deciphering the mechanism of apoptosis induced by emodin. At present, its role in combination chemotherapy with standard drugs to reduce toxicity and to enhance efficacy is pursued vigorously. Its additional inhibitory effects on angiogenic and metastasis regulatory processes make emodin a sensible candidate as a specific blocker of tumor-associated events. Additionally, because of its quinone structure, emodin may interfere with electron transport process and in altering cellular redox status, which may account for its cytotoxic properties in different systems. However, there is no documentation available which reviews the biological activities of emodin, in particular, its growth inhibitory effects. This review is an attempt to analyze the biological properties of emodin, a molecule offering a broad therapeutic window, which in future may become a member of anticancer armamentarium.

Absence of contact sensitization to Aloe vera (L.) Burm. f

Aloe vera has been used as a cosmetic and medical remedy since ancient times and has gained increasing popularity in recent years. Despite its widespread use, reports of allergic reactions are rare. We patch tested 702 consecutive patients with an oily extract from the leaves, Aloe pulvis from the entire plant and concentrated Aloe vera gel. A specially designed questionnaire was used for the use of Aloe vera, reasons and location of application, adverse reactions, occupation, hobbies and atopy. None of the subjects showed any reaction to one of the preparations. 2 components of the plant have to be distinguished: the bark of the leaves contains anthrachinones with pro-peristaltic and potential antibiotic and anticancer properties. Constraints have been imposed due to their considerable toxic potential. Today, mostly the Aloe gel from the center of the leaves is processed. It almost exclusively consists of carbohydrates to which also many medical effects have been attributed. Carbohydrates are not likely to induce contact sensitization, which might explain the outcome of our study. However, this does not justify unrestrained promotion of Aloe products, as scientific studies investigating the claims on its constitutional effects are few in number, and the majority of them have been unable to diminish the intuitive scepticism against miracle cures, like Aloe seems to be.