The diarrhoeogenic and antidiarrhoeal bidirectional effects of rhubarb and its potential mechanism

The phytochemistry and pharmacology of three Rheum species: A comprehensive review with future perspectives

BACKGROUND

Rheum palmatum, R. tanguticum, and R. officinale, integral species of the genus Rheum, are widely used across global temperate and subtropical regions. These species are incorporated in functional foods, medicines, and cosmetics, recognized for their substantial bioactive components.

PURPOSE

This review aims to synthesize developments from 2014 to 2023 concerning the botanical characteristics, ethnopharmacology, nutritional values, chemical compositions, pharmacological activities, mechanisms of action, and toxicity of these species.

METHODS

Data on the three Rheum species were gathered from a comprehensive review of peer-reviewed articles, patents, and clinical trials accessed through PubMed, Google Scholar, Web of Science, and CNKI.

RESULTS

The aerial parts are nutritionally rich, providing essential amino acids, fatty acids, and minerals, suitable for use as health foods or supplements. Studies have identified 143 chemical compounds, including anthraquinones, anthrones, flavonoids, and chromones, which contribute to their broad pharmacological properties such as laxative, anti-diarrheal, neuroprotective, hepatoprotective, cardiovascular, antidiabetic, antitumor, anti-inflammatory, antiviral, and antibacterial effects. Notably, the materials science approach has enhanced understanding of their medicinal capabilities through the evaluation of bioactive compounds in different therapeutic contexts.

CONCLUSION

As medicinal and economically significant herb species, Rheum species provide both edible aerial parts and medicinal underground components that offer substantial health benefits. These characteristics present new opportunities for developing nutritional ingredients and therapeutic products, bolstering the food and pharmaceutical industries.

Comprehensive identification strategy for rapid profiling of chemical constituents using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry with Rhubarb as an example

In this study, the collision induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation pathway of chemical components in rhubarb was wholly explored using 34 standards by UHPLC-QTOF-MS/MS in negative ion mode. In consequently, the diagnostic product ions for speedy screening and categorization of chemical components in rhubarb were ascertained based on their MS/MS splitting decomposition patterns and intensity analysis. According to these findings, a fresh two-step data mining strategy had set up. The initial key step involves the use of characteristic product ions and neutral loss to screen for different types of substituents and basic skeletons of compounds. The subsequent key step is to screen and classify different types of compounds based on their characteristic product ions. This method can be utilized for rapid research, classification, and identification of compounds in rhubarb. A total of 356 compounds were rapidly identified or tentatively characterized in three rhubarb species extracts, including 150 acylglucoside, 125 anthraquinone, 65 flavanols and 15 other compounds. This study manifests that the analytical strategy is feasible for the analysis of complex natural products in rhubarb.

Bidirectional regulation effect of rhubarb as laxative and astringent by metabolomics studies

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb, a prominent traditional Chinese medicine, has been employed as a potent laxative for centuries and garnered particular popularity among the youth owing to its notable efficacy in weight management. Historical records indicated that rhubarb initially exhibited robust laxative properties, but extended and consistent usage may lead to an astringent response in the later stage of long-term use. In contrast, steamed pieces of rhubarb (SR), preparing through the process of steaming with wine, have demonstrated a gentle laxative effect with no reported adverse effects.

AIM OF THE STUDY

Our study was designed to explore the intricate mechanisms underlying laxative and astringent properties of rhubarb through metabolomics research.

MATERIALS AND METHODS

In this investigation, we employed a serum metabolomics approach utilizing the UPLC-Q-Extractive-Orbitrap-MS method to delve into the contrasting laxative and astringent effects of rhubarb, as well as to unravel the mechanisms of underpinning its bidirectional regulatory influence. To commence, we assessed alterations in Evacuation Index (EI) values, intestinal hormone levels, and colon histopathology in mice to gauge rhubarb's laxative and astringent effects. Subsequently, metabolomics methodology was employed for cluster analysis through Principal Component Analysis (PCA) and biomarker identification via Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA). Then, we delved into the distinctions in characteristic biomarkers, metabolic pathways, their association with pathological changes, and correlation heatmap for biomarkers between raw pieces of rhubarb (RR) and SR to gain insights into the potential mechanisms behind rhubarb's bidirectional regulatory effects.

RESULTS

Our findings revealed that RR exhibited a laxative effect in the early stage and transitioned to an astringent effect in the later stage, as indicated by the EI values. In contrast, SR consistently demonstrated a mild laxative effect. Biochemical indexes and histopathological assessments unveiled that RR triggered its astringent effect by inhibiting secretion of motilin (MTL), promoting secretion of vasoactive intestinal peptide (VIP) and epinephrine (EPI), and inducing onset of inflammation. Furthermore, serum metabolomics analysis identified 59 discriminative biomarkers modulated by RR and SR. Through comprehensive analysis, we elucidated the in vivo transformation relationships among multiple endogenous metabolites. Notably, our results underscored the down-regulation of certain phosphatidylcholines (PCs), amino acids, acylcarnitines, and up-regulation of lysophosphatidylcholines (LysoPCs) played pivotal roles in the onset of gut dysfunction, intestinal inflammation, gut barrier damage, and gastrointestinal motility disorder upon prolonging RR administration, ultimately contributing to its astringent effect. Additionally, our correlation analysis elucidated that anthraquinones, stilbenes, and phenylbutanones were the pharmacodynamic material basis responsible for inducing the astringent effect of RR.

CONCLUSION

This study provides valuable insights into the bidirectional regulatory effects of rhubarb and sheds light on its underlying mechanisms through a comprehensive metabolomics approach.

Comparative antibacterial analysis of the anthraquinone compounds based on the AIM theory, molecular docking, and dynamics simulation analysis

BACKGROUND

Hydroxyanthraquinones and anthraquinone glucoside derivatives are always considered as the active antibacterial components.

METHODS

Comparison of structure characteristics and antibacterial effect of these compounds was performed by applying quantum chemical calculations, atoms in molecules theory, molecular docking, and dynamics simulation procedure. Density functional theory calculation with B3LYP using 6-31G (d, p) basis set has been used to determine ground state molecular geometries.

RESULTS

The molecular geometric stability, electrostatic potential, frontier orbital energies, and topological properties were analyzed at the active site. Once glucose ring is introduced into the hydroxyanthraquinone rings, almost all of the positive molecular potentials are distributed among the hydroxyl hydrogen atoms of the glucose rings. In addition, low electron density ρ (r) and positive Laplacian value of the O-H bond of the anthraquinone glucoside are the evidences of the highly polarized and covalently decreased bonding interactions. The anthraquinone glucoside compounds have generally higher intermolecular binding energies than the corresponding aglycones due to the strong interaction between the glucose rings and the surrounding amino acids. Molecular dynamics simulations further explored the stability and dynamic behavior of the anthraquinone compound and protein complexes through RMSD, RMSF, SASA, and Rg.

CONCLUSION

The type of carboxyl, hydroxyl, and hydroxymethyl groups on phenyl ring and the substituent glucose rings is important to the interactions with the topoisomerase type II enzyme DNA gyrase B.

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.

Bidirectional effects and mechanisms of traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

The bidirectional property of traditional Chinese medicines (TCMs) was recorded in the classic work Medicine Origin (Yi Xue Qi Yuan) as early as the Jin and Yuan dynasties of ancient China. Since then, this imperative theory has been applied to guide the clinical application of TCMs. Studies have been performed to investigate this phenomenon only over the last three decades. A limited number of reviews on the bidirectional role of TCMs have been published, and almost all current studies are published in the Chinese language.

AIM OF THE REVIEW

The aim of this review is to provide the first comprehensive evidence regarding the bidirectional effects and the underlying mechanisms of TCMs and their active compounds.

MATERIALS AND METHODS

Information relevant to opposing pharmacological activities or opposing properties exerted by TCM prescriptions, herbal medicines, and their active compound, as well as their mechanisms was summarized by searching Chinese and English databases, including the Chinese National Knowledge Infrastructure (CNKI), Wan Fang Data, Chinese Scientific Journal Database (VIP), Google Scholar, PubMed, Web of Science, Science Direct, and Wiley Online Library.

RESULTS

Although the bidirectional regulation of TCMs has been applied in the clinic since ancient times in China, only limited reviews have been published in Chinese. The existing data showed that bidirectional effects can be found in TCM prescriptions, herbal medicines, and pure active compounds. Additionally, the bidirectional role of TCMs was primarily reported in the modulation of immune function, blood circulation and hemostasis, gastrointestinal motility, the central nervous system and blood pressure. This may because the therapeutic outcomes of these disorders are more obvious than those of other complicated diseases. Intriguingly, some herbal medicines have multiple bidirectional activities; for instance, Panax ginseng C. A. Meyer showed bidirectional regulation of immune function and the central nervous system; Astragalus membranaceus can bidirectionally regulate blood pressure and immune function; and Rheum officinale Baill exerts bidirectional effects on blood circulation and hemostasis, gastrointestinal motility and immune function. The mechanisms underlying the bidirectional effects of TCMs are largely attributed to the complexity of herbal constituents, dosage differences, the processing of herbal medicine, and compatibility of medicines, the physiological conditions of patients and adaptogenic effects.

CONCLUSION

Uncovering the bidirectional effects and mechanisms of TCMs is of great importance for both scientific research and clinical applications. This review may help to facilitate the recognition of the bidirectional role of TCMs, to explain some seemingly-opposite phenomena in the pharmacological study of herbal medicines and to provide guidance for TCM practitioners.

The application of Tong-fu therapeutic method on ulcerative colitis: A systematic review and meta-analysis for efficacy and safety of rhubarb-based therapy

Background: Tong-fu therapeutic method (TFTM) is a traditional Chinese medicine treatment method for ulcerative colitis, which is a novel treatment strategies and have purgative effect. As the most representative medicinal of TFTM, Rhubarb has been reported to have a therapeutic impact on ulcerative colitis by regulating intestinal flora, anti-inflammation, and improving intestinal microcirculation. Although rhubarb has been widely used in Chinese medicine for the treatment of ulcerative colitis, the appropriate protocol is still demanded to its rational use in clinic, which promoted to evaluate the efficacy and safety for rhubarb-based therapy on ulcerative colitis.

Method: Clinical trials were searched through PubMed, Cochrane Library, Web of Science, Excerpta Medica Database, Chinese National Knowledge Infrastructure, WAN FANG Database, Chinese Scientific Journal Database, and Chinese Biomedical Literature Database. The subgroup analyses were performed with three groups: medication, course of treatment, and route of administration. The statistical analyses were performed on Review Manager software (version 5.4.1).

Results: A total of 2, 475 patients in 30 original studies were analyzed in this article. It was found that rhubarb-based therapy could increase clinical efficacy and reduce the recurrence rate. Subgroup analyses showed that rhubarb-based therapy was more effective than 5-aminosalicylic acid or sulfasalazine alone. In addition, the hypercoagulable state of ulcerative colitis could be ameliorated by decreasing platelet (PLT) and fibrinogen (FIB), and increasing prothrombin time (PT) significantly. Moreover, C-reaction protein (CRP), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and IL-1β expression were significantly reduced, while IL-10 production was increased, which mediated the alleviation of intestinal inflammation stress.

Conclusion: Rhubarb-based therapy could effectively improve ulcerative colitis. Of note, the rhubarb-based medicinal formulas combined with 5-ASA or SASP are more effective than the 5-ASA or SASP alone. In addition, although rhubarb has side effect, the results of our analysis showed that rhubarb-based therapy did not exhibit significant side effects. This means it has a high safety profile in clinical use. Moreover, the use of rhubarb-based therapy is recommend to use within 1–13 weeks or 3 months via administered orally or by enema, which is contributes to ensure the curative effect and avoid its toxic and side effects. As an important case of TFTM, rhubarb-based therapy provides evidence for the practical application of TFTM.

Hepatotoxic metabolites in Polygoni Multiflori Radix— Comparative toxicology in mice

Polygoni Multiflori Radix (PM) and Rhei radix et rhizoma (rhubarb) contain similar hepatocyte-toxic anthraquinones such as emodin (major free anthraquinone in PM), physcion and their glycosides. In clinical practice, PM hepatotoxicity has been widely reported, although rhubarb is not recognized as hepatotoxic. To clarify the substances basis (key components) of PM hepatotoxicity, based on the characteristic components’ similarity within PM, rhubarb and their concocted forms, a comparative sub-acute toxicity study was designed in mice. Nine groups of mice with 28 days of oral administration of these herbal extracts or 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (TSG, major and unique characteristic component in PM)-herb combinations were set as follows: Group-1, control; Group-2, PM ethanol-extract (PME); Group-3, PM praeparata ethanol-extract (PMPE); Group-4, Rhubarb ethanol-extract (RME); Group-5, Steamed rhubarb ethanol-extract (RMPE); Group-6, TSG; Group-7, PMPE-TSG combination; Group-8, RME-TSG combination; Group-9, RMPE-TSG combination. Each experimental group received an equivalent emodin dose of 29 mg/kg except for the TSG group, and an equivalent TSG dose of 1,345 mg/kg except for the PMPE, RME and RMPE groups. The results showed that PME, PMPE-TSG and RME-TSG induced liver lesions and biochemical abnormalities of liver function compared with the control. In contrast, PMPE, RME, RMPE, TSG and RMPE-TSG caused no liver lesions and fewer biochemical abnormalities. Considering the related components, only the co-administration of high doses of TSG and emodin-8-O-β-D-glucoside (EMG, major anthraquinone glycoside in PM) in these groups could cause liver lesions. According to tissue distribution and correlation analysis, EMG dose was positively correlated with the high hepatic emodin and TSG exposure, and the hepatic emodin and TSG exposure were positively correlated with the biochemical abnormalities of liver function. Cell viability test in vitro showed emodin was more hepatotoxic than TSG and EMG, and mainly emodin and TSG of the three had synergistic hepatotoxic effects. Therefore, creatively using rhubarb as a reference, this study revealed that PM hepatotoxicity in mice mainly came from the integrative contribution of TSG, EMG and emodin.

Determination of multiple active constituents in Da-Huang-Xiao-Shi decoction using HPLC-LTQ-Orbitrap mass spectrometry: Application in comparing the differences in the formula and its constituent herbs

Da-Huang-Xiao-Shi decoction (DHXSD) is a traditional Chinese medicine formula and is used to treat cholestasis. In this study, we developed a reliable and comprehensive HPLC coupled with linear ion trap-Orbitrap mass spectrometry method for the separation and determination of 21 components including six alkaloids, five anthraquinones, three tannins, three terpenes, two iridoid glycosides, one organic acid, and one flavonoid in DHXSD. A C₁₈ column was eluted by a gradient mobile phase containing at a flow rate of 1 mL/min. Detection was operated with electrospray ionization source in positive and negative ion modes using selective ion monitoring (SIM). The calibration curves for all analytes showed good linearity (r >0.9901), and the inter- and intra-day precision did not exceed 4.98%. The recoveries, repeatability, and stability were also within the acceptable limits. The method was successfully applied to determine multiple active constituents in DHXSD and its constituent herbs. Compared to Da Huang, the total contents of the five anthraquinones were significantly higher in DHXSD. However, the changes of components from Zhi Zi/Huang Bo were complicated in DHXSD. The study could serve as a fundamental reference for establishing comprehensive DHXSD quality control measures and be helpful to understand some compatibility laws of DHXSD.

Oroxylin a Attenuates Limb Ischemia by Promoting Angiogenesis via Modulation of Endothelial Cell Migration

Oroxylin A (OA) has been shown to simultaneously increase coronary flow and provide a strong anti-inflammatory effect. In this study, we described the angiogenic properties of OA. OA treatment accelerated perfusion recovery, reduced tissue injury, and promoted angiogenesis after hindlimb ischemia (HLI). In addition, OA regulated the secretion of multiple cytokines, including vascular endothelial growth factor A (VEGFA), angiopoietin-2 (ANG-2), fibroblast growth factor-basic (FGF-2), and platelet derived growth factor BB (PDGF-BB). Specifically, those multiple cytokines were involved in cell migration, cell population proliferation, and angiogenesis. These effects were observed at 3, 7, and 14 days after HLI. In skeletal muscle cells, OA promoted the release of VEGFA and ANG-2. After OA treatment, the conditioned medium derived from skeletal muscle cells was found to significantly induce endothelial cell (EC) proliferation. OA also induced EC migration by activating the Ras homolog gene family member A (RhoA)/Rho-associated coiled-coil kinase 2 (ROCK-II) signaling pathway and the T-box20 (TBX20)/prokineticin 2 (PROK2) signaling pathway. In addition, OA was able to downregulate the number of macrophages and neutrophils, along with the secretion of interleukin-1β, at 3 days after HLI. These results expanded current knowledge about the beneficial effects of OA in angiogenesis and blood flow recovery. This research could open new directions for the development of novel therapeutic intervention for patients with peripheral artery disease (PAD).

Jaboticaba berry: A comprehensive review on its polyphenol composition, health effects, metabolism, and the development of food products

Jaboticaba, a popular Brazilian berry, has been studied due to its relevant polyphenol composition, health benefits and potential use for the development of derived food products. Considering that around 200 articles have been published in recent years, this review aims to provide comprehensive and updated information, as well as a critical discussion on: (i) jaboticaba polyphenolic composition and extraction methods for their accurate determination; (ii) jaboticaba polyphenol's metabolism; (iii) biological effects of the fruit and the relationship with its polyphenols and their metabolites; (iv) challenges in the development of jaboticaba derived products. The determination of jaboticaba polyphenols should employ hydrolysis procedures during extraction, followed by liquid chromatographic analysis. Jaboticaba polyphenols, mainly anthocyanins and ellagitannins, are extensively metabolized, and their metabolites are probably the most important contributors to the relevant health effects associated with the fruit, such as antioxidant, anti-inflammatory, antidiabetic, hepatoprotective and hypolipidemic. Most of the technological processing of jaboticaba fruit and its residues is related to their application as a colorant, antioxidant, antimicrobial and source of polyphenols. The scientific literature still lacks studies on the metabolism and bioactivity of polyphenols from jaboticaba in humans, as well as the effect of technological processes on these issues.

Antidiarrheal, antimicrobial and antioxidant potentials of methanol extract of Colocasia gigantea Hook. f. leaves: evidenced from in vivo and in vitro studies along with computer-aided approaches

BACKGROUND

Colocasia gigantea, locally named as kochu is well-known due to its various healing power. This research is to investigate the antidiarrheal, antimicrobial and antioxidant possibilities of the methanol soluble extract of Colocasia gigantea.

METHODS

The antidiarrheal investigation was performed by using in vivo castor oil-induced diarrheal method whereas in vitro antimicrobial and antioxidant investigation have been implemented by disc diffusion and DPPH scavenging method respectively. Moreover, in silico studies were followed by molecular docking analysis of several secondary metabolites that were appraised with Schrödinger-Maestro v11.1 and Biovia Discovery Studio.

RESULTS

The induction of plant extract (200 and 400 mg/kg, b.w, p.o) has minimized the castor oil mediated diarrhea by 16.96% (p < 0.01) and 38.89% (p < 0.001) respectively compared to control group. The methanol extract of C. gigantea showed mild sensitivity against almost all the tested strains but it shows high consistency of phenolic content and yielded 67.68 μg/mL of IC50 value in the DPPH test. In the PASS prediction, selected isolated compounds have demonstrated significant antidiarrheal and antimicrobial activity following the Lipinski drug rules which have ascertained efficacy with the compounds in molecular docking study.

CONCLUSION

The results of this scientific research reflects that the methanol soluble extract of C. gigantea is safe and may provide possibilities of alleviation of diarrhea along with being a potential wellspring of antioxidant and antimicrobial agents which can be considered as an alternate source for exploration of new medicinal products in near future.

Topical therapy with rhubarb navel plasters in patients with chronic constipation: Results from a prospective randomized multicenter study

ETHNOPHARMACOLOGICAL RELEVANCE

Constipation is a functional gastrointestinal disorder and one of the most prevalent conditions encountered in primary care settings. Rhubarb navel dressings have been used for more than 2,000 years in Chinese medicine to treat constipation. However, the effect of topical rhubarb administration has still not been well recognized and this strategy is not yet established as an evidence-based approach.

AIM OF THE STUDY

In this study, we performed a prospective multicentric randomized controlled trial to evaluate the efficacy and safety of rhubarb navel plasters for patients with chronic constipation.

MATERIALS AND METHODS

A total of 374 patients from six teaching hospitals were prospectively included between 09/2016 and 10/2017 in the study based on Rome III criteria. All participants were randomly assigned (1:1) into verum/placebo group and given either Rheum officinale rhubarb powder or a placebo flour stick on the navel for 6 h/day/8 days. Primary outcome measures were the Cleveland Constipation Score (CCS) for the feces condition and Bristol Stool Scale (BSS) for stool consistency and 24 h defecation frequency.

RESULTS

The groups demonstrated no statistical differences in demographic data, clinical diagnoses and concomitant medication at baseline. In patients treated with the verum CCS was 5.61 (day 8, 95% CI 5.15-6.07) compared to 8.62 (95% CI 8.07-9.18) in placebo-treated controls (P < 0.001). The mean change of CCS at the end of treatment (day 8 versus [vs] day 0) was 6.04 in verum-treated vs 2.73 in placebo-treated controls (P < 0.001). Also 24 h defecation frequency (BSS) showed superior results (day 5: 0.84 vs 0.62, 95% CI 0.67-0.80, P < 0.001; day 6: 0.82 vs 0.60, 95% CI 0.64-0.78, P < 0.01 and day 8: 0.82 vs 0.60, 95% CI 0.64-0.78, P < 0.01) and better BSS type classification during treatment than controls (P < 0.05). No significant differences in adverse events between both groups became obvious.

CONCLUSION

Rhubarb navel plaster administration over an 8-day-treatment period resulted in significantly improved bowel function as demonstrated by the CCS, 24 h defecating frequency and BSS. Our results suggest that rhubarb navel plasters represent a feasible, safe and efficient application route for the treatment of patients suffering from chronic constipation.

What we already know about rhubarb: a comprehensive review

Rhubarb (also named Rhei or Dahuang), one of the most ancient and important herbs in traditional Chinese medicine (TCM), belongs to the Rheum L. genus from the Polygonaceae family, and its application can be traced back to 270 BC in "Shen Nong Ben Cao Jing". Rhubarb has long been used as an antibacterial, anti-inflammatory, anti-fibrotic and anticancer medicine in China. However, for a variety of reasons, such as origin, variety and processing methods, there are differences in the effective components of rhubarb, which eventually lead to decreased quality and poor efficacy. Additionally, although some papers have reviewed the relationship between the active ingredients of rhubarb and pharmacologic actions, most studies have concentrated on one or several aspects, although there has been great progress in rhubarb research in recent years. Therefore, this review aims to summarize recent studies on the geographic distribution, taxonomic identification, pharmacology, clinical applications and safety issues related to rhubarb and provide insights into the further development and application of rhubarb in the future.

The beneficial influence of rhubarb on 5-fluorouracil-induced ileal mucositis and the combined role of aquaporin-4, tumour necrosis factor-α, nuclear factor-kappa B & matrix metalloproteinase-9 in rat model: histological study

A 5-fluorouracil (5-FU) is used for cancer treatment despite its cytotoxic sequelae on healthy cells, especially the rapid proliferating ones. Intestinal mucositis is one of the most frequent chemotherapeutic debilitating sequelae. Rhubarb (Rh), an ancient herb, is known for its curing effect on gastrointestinal complications. This study aims to detect the role of aquaporin-4 (AQP-4), tumour necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-κB), and matrix metalloproteinase-9 (MMP-9) in 5-FU-induced ileal histological and biochemical changes and the potential therapeutic effect of Rh water extract on these changes in rats. A 45 rats were divided into 3 groups; control, 5-FU (single intraperitoneal injection of 150 mg/kg/rat) and Rh-treated (oral 20 mg/kg/day/rat for 8 days). The change in animals’ weight, incidence of diarrhoea and AQP-4 and TNF-α values in ileal homogenates were measured. Ileal sections were subjected to hematoxylin and eosin stain, periodic acid Schiff (PAS)-reaction and MMP-9, NF-κB and AQP-4 immunohistochemical staining. A 5-FU group revealed marked ileal mucosal damage associated with a significant decrease in the mean body weight, AQP-4 level and area percent of PAS and AQP-4 positive reaction. Significant increase in the mean incidence of diarrhoea, TNF-α value and area percent of MMP-9 and NF-κB was detected. These changes were significantly corrected with Rh administration. A 5-FU resulted in severe ileal mucositis through TNF-α, NF-κB, MMP-9, and AQP-4 disturbances. Rh treatment was highly effective in preventing such mucositis.

Development of a direct ESI-MS method for measuring the tannin precipitation effect of proline-rich peptides and in silico studies on the proline role in tannin-protein interactions

Tannins are a heterogeneous class of polyphenols that are present in several plants and foods. Their ability to interact and precipitate proline-rich proteins leads to different effects such as astringency or antidiarrheal activity. Thus, evaluation of the tannin content in plant extracts plays a key role in understanding their potential use as pharmaceuticals and nutraceuticals. Several methods have been proposed to study tannin-protein interactions but few of them are focused on quantification. The purpose of the present work is to set up a suitable and time efficient method able to quantify the extent of tannin protein precipitation. Bradykinin, chosen as a model, was incubated with increasing concentrations of 1,2,3,4,6-penta-O-galloyl-β-d-glucose and tannic acid selected as reference of tannic compounds. Bradykinin not precipitated was determined by a mass spectrometer TSQ Quantum Ultra Triple Quadrupole (direct infusion analysis). The results were expressed as PC₅₀, which is the concentration able to precipitate 50% of the protein. The type of tannin-protein interaction was evaluated also after precipitate solubilisation. The involvement of proline residues in tannin-protein interactions was confirmed by repeating the experiment using a synthesized peptide (RR-9) characterized by the same bradykinin sequence, but having proline residues replaced by glycine residues: no interaction occurred between the peptide and the tannins. Moreover, modelling studies on PGG-BK and PGG-RR-9 were performed to deeply investigate the involvement of prolines: a balance of hydrophobic and H-bond contacts stabilizes the PGG-BK cluster and the proline residues exert a crucial role thus allowing the PGG molecules to elicit a sticking effect.

Lactobacillus casei Strain Shirota Alleviates Constipation in Adults by Increasing the Pipecolinic Acid Level in the Gut

The benefits of probiotics for constipation are widely accepted, but the mechanisms involving gut metabolites are unclear. In this study, we investigated the effects of Lactobacillus casei strain Shirota (LcS) on constipated patients and revealed that a metabolite mediator is involved in the LcS-induced constipation alleviation. Sixteen constipated patients and 22 non-constipated participants were recruited. The subjects consumed 100 mL of an LcS beverage (10⁸ CFU/mL) per day for 28 days. The fecal non-volatile metabolites were determined by GC/MS, and the targeted metabolites were further verified in a constipated mouse model. In constipated patients, LcS intervention significantly improved defecation frequency (from 4.81 to 7.81 times per week, p < 0.05), stool consistency (from 2.52 to 3.68, p < 0.05) and constipation-related symptoms. A total of 14 non-volatile fecal metabolites were obtained as potential constipation-related metabolites that were regulated by LcS. Among these metabolites, pipecolinic acid (PIPA) had a significant positive correlation with defecation frequency in constipated patients. PIPA significantly promoted the small intestinal propulsive rate (from 25.45 to 39.68%) and increased the number of fecal pellets (from 30.38 to 57.38 pellets) in constipated mice (p < 0.05). The 5-hydroxytryptamine (5-HT) and acetylcholine (ACh) in colonic tissue may be partly involved in PIPA-mediated constipation alleviation. In conclusion, PIPA was a metabolic mediator in the gut that participated in LcS-induced constipation alleviation.

Emodin-induced hepatotoxicity was exacerbated by probenecid through inhibiting UGTs and MRP2

Aggravating effect of probenecid (a traditional anti-gout agent) on emodin-induced hepatotoxicity was evaluated in this study. 33.3% rats died in combination group, while no death was observed in rats treated with emodin alone or probenecid alone, indicating that emodin-induced (150 mg/kg) hepatotoxicity was exacerbated by probenecid (100 mg/kg). In toxicokinetics-toxicodynamics (TK-TD) study, aspartate aminotransferase (AST) and systemic exposure (area under the serum concentration-time curve, AUC) of emodin and its glucuronide were significantly increased in rats after co-administrated with emodin and probenecid for 28 consecutive days. Results showed that the increased AUC (increased by 85.9%) of emodin was mainly caused by the decreased enzyme activity of UDP-glucuronosyltransferases (UGTs, decreased by 11.8%-58.1%). In addition, AUC of emodin glucuronide was increased 5-fold, which was attributed to the decrease of multidrug-resistant-protein 2 (MRP2) protein levels (decreased by 54.4%). Similarly, in vitro experiments proved that probenecid reduced the cell viability of emodin-treated HepG2 cells through inhibiting UGT1A9, UGT2B7 and MRP2. Our findings demonstrated that emodin-induced hepatoxicity was exacerbated by probenecid through inhibition of UGTs and MRP2 in vivo and in vitro, indicating that gout patients should avoid taking emodin-containing preparations in combination with probenecid for a long time.

Biochemical, hematological, and hormonal profile of rats orally administered methanol stem bark extract of Napoleona vogelii Hook and Planch (Lecythidaceae)

Napoleona vogelii is used in traditional medicine for the management of stomach aches, ulcer, and cancers. This study was conducted to investigate the subchronic toxicological effect of methanol stem bark extract of N. vogelii on biochemical, hematological, and hormonal profile of male and female rats. Forty rats of both sexes were randomly divided into four groups of 10 rats each and were administered 100, 200, and 400 mg/kg of the extract p.o. for 90 d. Ten milliliter per kilogram of distilled water p.o. was administered to control rats. On hematological assessment, mean corpuscular hemoglobin concentration was significantly (p < 0.01) increased at 400 mg/kg compared to control. Biochemical assessment showed a significant increase (p < 0.05) in levels of alanine aminotransferase and aspartate aminotransferase at 200 and 400 mg/kg, respectively, compared to control. Hormonal assessment of male rats revealed a significantly (p < 0.0001) reduced level of testosterone at all treatment doses compared to control while estradiol was significantly (p < 0.05) reduced at 100 mg/kg, but significantly (p < 0.0001) increased at 200 and 400 mg/kg respectively compared to control in female rats. Findings from this study demonstrate that N. vogelli is relatively safe on oral acute exposure but may possess the potential to cause hepatic dysfunction and infertility in male rats by perturbations of the hypothalamic-pituitary axis while conversely enhancing fertility in female rats on subchronic administration.

Screening in larval zebrafish reveals tissue-specific distribution of fifteen fluorescent compounds

The zebrafish is a prominent vertebrate model for low-cost in vivo whole organism screening. In our recent screening of the distribution patterns of fluorescent compounds in live zebrafish larvae, fifteen compounds with tissue-specific distributions were identified. Several compounds were observed to accumulate in tissues where they were reported to induce side-effects, and compounds with similar structures tended to be enriched in the same tissues, with minor differences. In particular, we found three novel red fluorescent bone-staining dyes: purpurin, lucidin and 3-hydroxy-morindone; purpurin can effectively label bones in both larval and adult zebrafish, as well as in postnatal mice, without significantly affecting bone mass and density. Moreover, two structurally similar chemotherapeutic compounds, doxorubicin and epirubicin, were observed to have distinct distribution preferences in zebrafish. Epirubicin maintained a relatively higher concentration in the liver, and performed better in inhibiting hepatic hyperplasia caused by the over-expression of krasG12V In total, our study suggests that the transparent zebrafish larvae serve as valuable tools for identifying tissue-specific distributions of fluorescent compounds.

Oral colon-specific drug delivery system reduces the nephrotoxicity of rhubarb anthraquinones when they produce purgative efficacy

Rhubarb is commonly used to treat constipation in China and anthraquinones (AQs) are the active components present in rhubarb. However, an increasing number of studies have reported that AQs induce nephrotoxicity. In the present study, rhubarb total free anthraquinones (RTFA) oral colon-specific drug delivery granules (RTFA-OCDD-GN) were prepared to determine whether RTFA-OCDD-GN could reduce the nephrotoxicity that occurs when AQs produce purgative efficacy. RTFA-OCDD-GN were prepared using pH-enzyme double-layer coating technology and the cumulative release rate of RTFA in RTFA-OCDD-GN was assessed. The first black stool time, the number and state of feces over 8 h were observed to measure the purgative efficacy. In the nephrotoxicity test, biochemical and histopathological examinations were performed following 20 and 40 days administration, and 20 days convalescence. The cumulative release rate of RTFA in RTFA-OCDD-GN was >80% in simulated colonic fluid. RTFA-OCDD-GN produced considerable purgative efficacy compared with rhubarb medical material samples (RMMS). Following 40 days RMMS administration, blood urea nitrogen, creatinine and urine β₂-microglobulin levels in the high-dosage group were significantly increased compared with the control and RTFA-OCDD-GN groups (P<0.05). All specimens from the high-dosage RMMS group exhibited swelling/degeneration of renal proximal convoluted tubule epithelial cells. No difference in pathological conditions and biochemical indicators was detected between the RTFA-OCDD-GN groups and the control group. The nephrotoxicity of AQs was significantly reduced following RTFA-OCDD-GN administration, which produced considerable purgative efficacy compared with RMMS.

Data fusion of near-infrared and mid-infrared spectra for identification of rhubarb

Rhubarb has different medicinal efficacy to official rhubarb and may affect the clinical medication safety. In order to guarantee the quality of rhubarb, we established a method to distinguish unofficial rhubarbs. 52 official and unofficial rhubarb samples were analyzed using near-infrared (NIR) spectroscopy and mid-infrared (MIR) spectroscopy for classification. The feature vectors, which were selected by wavelet compression (WC) and interval partial least squares (iPLS) from NIR, MIR spectra, were fused together for identifying rhubarb samples. Partial least squares-discriminant analysis (PLS-DA), soft independent modeling of class analogies (SIMCA), support vector machine (SVM) and artificial neural network (ANN) were compared for classifying rhubarb. The use of data fusion strategies improved the classification model and allowed correct classification of all the samples.

Rhubarb extract partially improves mucosal integrity in chemotherapy-induced intestinal mucositis

AIM

To investigate the effects of orally gavaged aqueous rhubarb extract (RE) on 5-fluorouracil (5-FU)-induced intestinal mucositis in rats.

METHODS

Female Dark Agouti rats (n = 8/group) were gavaged daily (1 mL) with water, high-dose RE (HDR; 200 mg/kg) or low-dose RE (LDR; 20mg/kg) for eight days. Intestinal mucositis was induced (day 5) with 5-FU (150 mg/kg) via intraperitoneal injection. Intestinal tissue samples were collected for myeloperoxidase (MPO) activity and histological examination. Xenopus oocytes expressing aquaporin 4 water channels were prepared to examine the effect of aqueous RE on cell volume, indicating a potential mechanism responsible for modulating net fluid absorption and secretion in the gastrointestinal tract. Statistical significance was assumed at P < 0.05 by one-way ANOVA.

RESULTS

Bodyweight was significantly reduced in rats administered 5-FU compared to healthy controls (P < 0.01). Rats administered 5-FU significantly increased intestinal MPO levels (≥ 307%; P < 0.001), compared to healthy controls. However, LDR attenuated this effect in 5-FU treated rats, significantly decreasing ileal MPO activity (by 45%; P < 0.05), as compared to 5-FU controls. 5-FU significantly reduced intestinal mucosal thickness (by ≥ 29% P < 0.001) as compared to healthy controls. LDR significantly increased ileal mucosal thickness in 5-FU treated rats (19%; P < 0.05) relative to 5-FU controls. In xenopus oocytes expressing AQP4 water channels, RE selectively blocked water influx into the cell, induced by a decrease in external osmotic pressure. As water efflux was unaltered by the presence of extracellular RE, the directional flow of water across the epithelial barrier, in the presence of extracellular RE, indicated that RE may alleviate water loss across the epithelial barrier and promote intestinal health in chemotherapy-induced intestinal mucositis.

CONCLUSION

In summary, low dose RE improves selected parameters of mucosal integrity and reduces ileal inflammation, manifesting from 5-FU-induced intestinal mucositis.

Molecular ion index assisted comprehensive profiling of B-type oligomeric proanthocyanidins in rhubarb by high performance liquid chromatography-tandem mass spectrometry

Proanthocyanidins (PAs) are major anti-diarrhea constituents in rhubarb, one of the frequently used traditional medicines. However, the phytochemical investigation of PAs in rhubarb was hampered by their strenuous purification and identification. In the present study, aiming to clarify the distribution of PAs in different rhubarb species, a molecular ion index was priorly established according to the structural features of B-type PAs, which led to a series of targeted discovery of oligomeric PAs in rhubarb by the HPLC-ESI-MS/MS method. Totally, 66 oligomeric PAs including 27 dimers, 29 trimers, and 10 tetramers were tentatively identified on the basis of their MS/MS spectra from 28 rhubarb samples derived from 5 Rheum species as R. palmatum, R. tanguticum, R. officinale, R. coreanum, and R. laciniatum. It is noteworthy that 6 propelargonidins, 14 prodelphinidins, and 10 procyanidin-tetramers were identified from rhubarb for the first time. The profiling comparison of these oligomeric PAs in different rhubarb samples was achieved by visualizing their abundance in a heat map, which indicated the dominant PAs in rhubarb were procyanidin-dimer and its galloylated derivatives.

Influence of wine-processing on the pharmacokinetics of anthraquinone aglycones and glycosides from rhubarb in hyperlipidemic hamsters

A high performance liquid chromatography-tandem mass spectrometry method was developed to investigate the influence of wine-processing on pharmacokinetics of anthraquinones from rhubarb in hyperlipidemic hamsters.

Effect of rhubarb (Rheum emodi) in primary dysmenorrhoea: a single-blind randomized controlled trial

BACKGROUND

The aim of this study was to investigate and evaluate the efficacy of Rheum emodi in the management of primary dysmenorrhoea.

METHODS

A randomized, single-blind, standard controlled trial compared efficacy of R. emodi against mefenamic acid on diagnosed subjects of primary dysmenorrhoea for three consecutive cycles. Experimental group (n=30) received capsules of R. emodi powder two times a day, two days before the expected date of menstruation, and continued first three days of menstruation, while control group (n=15) participants received mefenamic acid capsules three times a day on the same protocol. The primary outcome measures were reduced in severity and duration of pain, assessed by visual analogue scale (VAS) and verbal multidimensional scoring system (VMSS), and secondary outcome measures were overall improvement of dysmenorrhoea and improved in quality of life (QOL). Statistical analysis was done by repeated measures analysis of variance and Chi-square/Fisher Exact test.

RESULTS

The menstrual pain was significantly decreased in both groups after three-cycle intervention. Significant changes were observed in VAS (p<0.001) and VMSS (p<0.001) in the experimental group. There is a significant (p<0.001) reduction in duration of pain in both the groups. Associated symptoms and QOL were markedly improved after treatment (p<0.001).

CONCLUSIONS

It has been clear from the above result that R. emodi is an effective herb in alleviating symptoms of primary dysmenorrhoea. It can serve as an alternative treatment without any apparent side effects. These results deserve further investigations.

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.

Flos Albiziae aqueous extract and its active constituent quercetin potentiate the hypnotic effect of pentobarbital via the serotonergic system

Flos albiziae (FA) is reportedly used for treatment of insomnia and anxiety in traditional medicine. The hypnotic effect of an extract of FA (FAE) and its constituent quercetin [2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one, QR] was examined in mice. QR is a widely distributed natural flavonoid abundant in FA flowers and other tissues. The possible mechanisms underlying the hypnotic effects of FAE and QR were investigated using behavioral pharmacology. FAE and QR significantly potentiated pentobarbital-induced [50 mg/kg, intraperitoneal (ip)] sleep (prolonged sleeping time; shortened sleep latency) in a dose-dependent manner, and these effects were augmented by administration of 5-hydroxytryptophan (5-HTP), a precursor of 5-hydroxytryptamine. With a sub-hypnotic dose of pentobarbital (28 mg/kg, ip), FAE and QR significantly increased the rate of sleep onset and were synergistic with 5-HTP (2.5 mg/kg, ip). Pretreatment with p-chlorophenylalanine, an inhibitor of tryptophan hydroxylase, significantly decreased sleeping time and prolonged sleep latency in pentobarbital-treated mice, whereas FAE and QR significantly reversed this effect. Data show that FAE and QR have hypnotic activity, possibly mediated by the serotonergic system. The present study offers a rationale for the use of FA in treating sleep disorders associated with serotonin system dysfunction.

A Systematic Review of Rhubarb (a Traditional Chinese Medicine) Used for the Treatment of Experimental Sepsis

Sepsis is a global major health problem in great need for more effective therapy. For thousands of years, Rhubarb had been used for various diseases including severe infection. Pharmacological studies and trials reported that Rhubarb may be effective in treating sepsis, but the efficacy and the quality of evidence remain unclear since there is no systematic review on Rhubarb for sepsis. The present study is the first systematic review of Rhubarb used for the treatment of experimental sepsis in both English and Chinese literatures by identifying 27 studies from 7 databases. It showed that Rhubarb might be effective in reducing injuries in gastrointestinal tract, lung, and liver induced by sepsis, and its potential mechanisms might include reducing oxidative stress and inflammation, ameliorating microcirculatory disturbance, and maintaining immune balance. Yet the positive findings should be interpreted with caution due to poor methodological quality. In a word, Rhubarb might be a promising candidate that is worth further clinical and experimental trials for sepsis therapy.

Global metabolite profiling and diagnostic ion filtering strategy by LC-QTOF MS for rapid identification of raw and processed pieces of Rheum palmatum L

Due to its variety of functions, rhubarb has been used for thousands of years in many countries. It is commonly used after processing. Processing usually affect the chemical profile and the contents of active compounds in herbals, leading to changes of their bioactivities. Here, an approach of metabolite profiling and diagnostic ion filtering strategy with liquid chromatography-quadrupole/time-of-flight mass spectrometry was established for rapid identification of raw and processed pieces of Rheum palmatum L. (RPL). The comprehensive and unbiased information of 30 batches of RPL covering raw and two general processing methods were given by metabolomic profiles. Using molecular feature extraction algorithm, non-targeted compounds were analyzed in minutes. In total, 73 characteristic markers were extracted and identified by diagnostic ion filtering. They have been further analyzed by partial least squares-support vector machine-based pattern recognition. The comprehensive and rapid method for raw and processed pieces of RPL classification shows good sensitivity, specificity and prediction performance.

Antidiarrheal effect of Alpinia oxyphylla Miq. (Zingiberaceae) in experimental mice and its possible mechanism of action

ETHNOPHARMACOLOGICAL RELEVANCE

The fructus Alpinia oxyphylla Miq. (AOM) has been used for treating diarrhea with spleen deficiency and gastralgia for thousands of years. A number of traditional Chinese medicine formulae provide AOM as an alternative herbal treatment for diarrhea, but the scientific basis for this usage has not been well defined.

AIM OF THE STUDY

In this study, we tried to investigate the antidiarrheal activity and possible mechanisms of Fructus AOM, aiming to enrich our understanding to the scientific meanings and theoretical significance of Fructus AOM in clinical practice.

MATERIALS AND METHODS

The fructus of AOM collected from Hainan province in China were macerated in the 95% ethanol to obtain the crude 95% ethanol extract, followed by subjected to chromatographic separation over a Diaion HP20 column to obtain 90% and 50% ethanol eluted fractions. The activities of the crude extract and fractions on castor oil induced acute diarrhea, rhubarb induced chronic diarrhea, gastrointestinal transit (GIT) in mice, and contractions of isolated guinea-pig ileum were evaluated. Additionally, nitric oxide (NO), gastrointestinal peptides gastrin (GAS), motilin (MTL) and somatostatin (SS) levels that related to gastrointestinal motilities were detected to demonstrate the potential mechanisms. Ultimately, LC-MS/MS method was utilized to ensure the chemical consistency.

RESULTS

The 95% ethanol extract and 90% ethanol eluted fraction significantly delayed the onset time and decreased the wet faeces proportion compared with control group in the castor oil induced acute diarrhea mice. In terms of further evaluation of antidiarrheal activity, the 95% ethanol extract and 90% ethanol elution displayed significant inhibition of the intestinal propulsion at the two highest oral doses of 20 g crude drug/kg and 1g/kg. Moreover the 95% ethanol extract (10 and 20 g crude drug/kg) and 90% ethanol elution (0.5 and 1g/kg) could significantly inhibit the GIT, which was partially attributed to the increase in NO and SS levels, and the decreased MTL. In vitro spontaneous contractions of the isolated guinea pig ileum induced by carbachol, neostigmine and histamine were attenuated by both the extract and elution. Phytochemical analysis of 95% ethanol extract and its fractions identified the presence of diphenylheptanes, sesquiterpenes, and flavones as the major components.

CONCLUSIONS

Our in vivo and in vitro data could partly support and justify the traditional usage of Fructus AOM on the treatment of diarrhea in traditional medicine.

The pharmacokinetic study on the mechanism of toxicity attenuation of rhubarb total free anthraquinone oral colon-specific drug delivery system

Rhubarb is commonly used as laxatives in Asian countries, of which anthraquinones are the major active ingredients, but there are an increased number of concerns regarding the nephrotoxicity of anthraquinones. In this study, we compared the pharmacokinetic characteristics of rhubarb anthraquinones in rats after orally administered with rhubarb and rhubarb total free anthraquinone oral colon-specific drug delivery granules (RTFA-OCDD-GN), and then explained why these granules could reduce the nephrotoxicity of anthraquinones when they produced purgative efficacy. A sensitive and reliable high performance liquid chromatography (HPLC) method has been fully validated for simultaneous determination of the five active components of rhubarb, and successfully applied to investigate and compare the remarkable differences in pharmacokinetic study of rhubarb anthraquinones after orally administered with rhubarb and RTFA-OCDD-GN. The results showed that, compared with rhubarb group, the AUC, Cmax, t1/2z and Vz/F of aloe-emodin, rhein, emodin and chrysophanol in rats receiving the RTFA-OCDD-GN were significantly decreased, and the Tmax of the four analytes was prolonged. Moreover, the Tmax of rhein, the Cmax of chrysophanol and emodin all have significant differences (P<0.05). Simultaneously, anthraquinone prototype excretion rates in urine and feces of aloe-emodin, rhein, emodin, chrysophanol and physcion were all increased. These findings suggested that oral colon-specific drug delivery technology made anthraquinone aglycone to colon-specific release after oral administration. This allowed anthraquinones to not only play the corresponding purgative effect but also avoid intestinal absorption and promote excretion. And thereby greatly reduced the nephrotoxicity of rhubarb. The result is a new breakthrough in rhubarb toxicity attenuated research.

Rhubarb tannins extract inhibits the expression of aquaporins 2 and 3 in magnesium sulphate-induced diarrhoea model

Tannins, a group of major active components of Chinese rhubarb and widely distributed in nature, have a significant antidiarrhoeal activity. Aquaporins (AQPs) 2 and 3 play important roles in regulating water transfer during diarrhoea. The present study aims to determine the effect of the total tannins extract of rhubarb on aquaporins (AQPs) 2 and 3 in diarrhoea mice and HT-29 cells both induced by magnesium sulphate (MgSO₄). Our results showed that rhubarb tannins extract (RTE) significantly decreased the faecal water content in colon and evaluation index of defecation of diarrhoea mice. Interestingly, RTE could markedly reduce the mRNA and protein expression levels of AQPs 2 and 3 in apical and lateral mucosal epithelial cells in the colons of diarrhoea mice and HT-29 cells both induced by MgSO₄ in a dose-dependent manner. Furthermore, RTE suppressed the production of cyclic monophosphate- (cAMP-) dependent protein kinase A catalytic subunits α (PKA C-α) and phosphorylated cAMP response element-binding protein (p-CREB, Ser133) in MgSO₄-induced HT-29 cells. Our data showed for the first time that RTE inhibit AQPs 2 and 3 expression in vivo and in vitro via downregulating PKA/p-CREB signal pathway, which accounts for the antidiarrhoeal effect of RTE.

Bidirectional effects of methanol extract of Wei-Chang-An pill on gastrointestinal transit and the spasmolytic activity on isolated rat jejunum

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Chang-An pill (WCA pill), a traditional Chinese medicine, has been used for treating various gastrointestinal diseases for several decades. Despite the popular medicinal use of WCA pill, less data was available to its activity and mechanism in gastrointestinal disorders. To examine the effects of the methanol extract of WCA pill (ME) on gastrointestinal tract so as to assess some of the possible mechanisms involved in the clinical treatment.

MATERIALS AND METHODS

ME was studied on gastrointestinal transit in vivo including gastric emptying and small intestinal motility in normal and neostigmine-induced mice, as well as on the isolated tissue preparations of rat jejunum in vitro.

RESULTS

In vivo, the gastric emptying decreased and intestinal transit increased after administration of ME in normal mice. However, administration of ME accelerated the intestinal transit ranging from 0.01 to 0.8 mg/mL and reduced it at the concentration of 1.6 and 3.2 mg/mL, while the gastric emptying was inhibited throughout the concentrations in neostigmine-induced mice. in vitro, ME caused inhibitory effect on the spontaneous contraction of rat-isolated jejunum in dose-dependent manner ranging from 0.01 to 6 mg/mL and also relaxed the acetylcholine chloride (Ach, 10(-6) M)-induced and K+ (60 mM)-induced contractions. ME shifted the Ca2+ concentration-response curves to right, similar to that caused by verapamil (0.025 mM).

CONCLUSIONS

These results indicated that ME might play a bidirectional role in gastrointestinal transit modulation and the effects on isolated tissue are probably mediated through calcium influx and muscarinic receptors, which provides pharmacological basis for the clinical use of WCA pill in gastrointestinal tract disorders.

Gut microbial diversity in rat model induced by rhubarb

Rhubarb is often used to establish chronic diarrhea and spleen (Pi)-deficiency syndrome animal models in China. In this study, we utilized the enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) method to detect changes in bacterial diversity in feces and the bowel mucosa associated with this model. Total microbial genomic DNA from the small bowel (duodenum, jejunum, and ileum), large bowel (proximal colon, distal colon, and rectum), cecum, and feces of normal and rhubarb-exposed rats were used as templates for the ERIC-PCR analysis. We found that the fecal microbial composition did not correspond to the bowel bacteria mix. More bacterial diversity was observed in the ileum of rhubarb-exposed rats (P<0.05). Furthermore, a 380 bp product was found to be increased in rhubarb-exposed rats both in faces and the bowel mucosa. The product was cloned and sequenced and showed high similarity with regions of the Bacteroides genome. AS a result of discriminant analysis with the SPSS software, the Canonical Discriminant Function Formulae for model rats was established.

A review on the traditional Chinese medicinal herbs and formulae with hypolipidemic effect

Hyperlipidemia, characterized by the abnormal blood lipid profiles, is one of the dominant factors of many chronic diseases such as diabetes, obesity, and cardiovascular diseases (CVD). For the low cost, effectiveness, and fewer side effects, the popularity of using traditional Chinese medicine (TCM) to handle hyperlipidemia is increasing and its role in health care has been recognized by the public at large. Despite the importance of TCM herbs and formulations, there is no comprehensive review summarizing their scientific findings on handling hyperlipidemia. This review summarizes the recent experimental and clinical results of nine representative single Chinese herbs and seven classic TCM formulae that could improve lipid profiles so as to help understand and compare their underlying mechanisms. Most of single herbs and formulae demonstrated the improvement of hyperlipidemic conditions with multiple and diverse mechanisms of actions similar to conventional Western drugs in spite of their mild side effects. Due to increasing popularity of TCM, more extensive, well-designed preclinical and clinical trials on the potential synergistic and adverse side effects of herb-drug interactions as well as their mechanisms are warranted. Hyperlipidemic patients should be warned about the potential risks of herb-drug interactions, particularly those taking anticoagulants and antiplatelet drugs.

Interaction of five anthraquinones from rhubarb with human organic anion transporter 1 (SLC22A6) and 3 (SLC22A8) and drug-drug interaction in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb is a well-known traditional Chinese medicine and has been used in China for thousands of years. Anthraquinone derivatives including rhein, emodin, aloe-emodin, chrysophanol and physcion are the important components in rhubarb.

MATERIALS AND METHODS

Here we studied the interaction of five anthraquinone derivatives with human renal organic anion transporter 1 (hOAT1) and hOAT3 stably expressed in cells, and interaction of rhein or rhubarb extract (RE) with furosemide (FS, substrate of OATs) in rats.

RESULTS

Uptake of 6-carboxyl fluorescein via hOAT1 and fluorescein via hOAT3 were markedly inhibited by rhein, emodin and aloe-emodin, and slightly inhibited by chrysophanol and physcion. The estimated IC₅₀ values for rhein, emodin, aloe-emodin and probenecid (typical inhibitor of hOAT1 and hOAT3) were 0.23, 0.61, 2.29 and 18.34 μM for hOAT1, and 0.08, 1.22, 5.37 and 5.83 μM for hOAT3, respectively. Furthermore, the data from the cellular accumulation assay indicated that these five compounds were not substrates of hOAT1 or hOAT3. Pharmacokinetic interaction between rhein and FS in rats showed that area under the curve (AUC₀-t) for FS was increased by 65% when coadministrated with rhein. RE was also used to interact with FS in rats and results showed that AUC₀-t of FS was increased by 32% and by 52% when coadministrated with single-dose or multiple-dose of RE, respectively.

CONCLUSIONS

These findings suggested that five anthraquinones inhibited hOAT1 and hOAT3, but these compounds were not transported by hOAT1 or hOAT3. Furthermore, rhein or RE, might cause drug-drug interaction when coadministrated with substrates of OAT1 or OAT3 in vivo.