Antioxidant constituents from rhubarb: structural requirements of stilbenes for the activity and structures of two new anthraquinone glucosides

Facile and selective separation of anthraquinones by alizarin-modified iron oxide magnetic nanoparticles

Anthraquinones are widely distributed in higher plants and possess broad biological activities. The conventional separation procedures for isolating anthraquinones from the plant crude extracts require multiple extraction, concentration, and column chromatography steps. In this study, we synthesized three alizarin (AZ)-modified Fe₃O₄ nanoparticles (Fe₃O₄@AZ, Fe₃O₄@SiO₂-AZ, and Fe₃O₄@SiO₂-PEI-AZ) by thermal solubilization method. Fe₃O₄@SiO₂-PEI-AZ showed strong magnetic responsiveness, high methanol/water dispersion, good recyclability, and high loading capacity for anthraquinones. To evaluate the feasibility of using Fe₃O₄@SiO₂-PEI-AZ for separating various aromatic compounds, we employed molecular dynamics simulations to predict the adsorption/desorption effects of PEI-AZ for various aromatic compounds in different methanol concentrations. The results showed that the anthraquinones could be efficiently separated from the monocyclic and bicyclic aromatic compounds by adjusting the methanol/water ratio. The Fe₃O₄@SiO₂-PEI-AZ nanoparticles were then used to separate the anthraquinones from the rhubarb extract. At 5% methanol, all the anthraquinones were adsorbed by the nanoparticles, thus allowing their separation from other components in the crude extract. Compared with the conventional separation methods, this adsorption method has the advantages of high adsorption specificity, simple operation, and solvent saving. This method sheds light on the future application of functionalized Fe₃O₄ magnetic nanoparticles to selectively separate desired components from complex plant and microbial crude extracts.

The effects of aqueous and ethanolic extracts of Rheum ribes on insulin-resistance and apolipoproteins in patients with type 2 diabetes mellitus: a randomized controlled trial

BACKGROUND AND AIM

Previous studies have shown that Rheum ribes (R. ribes) could be effective in controlling the blood glucose levels. This study was conducted to determine the effects of R. ribes supplementation on glycemic indices and apolipoproteins in patients with type 2 diabetes mellitus (T2DM).

METHODS

In the present randomized double-blind controlled trial, 60 type 2 diabetic patients aged 30-60 years with a body mass index (BMI) of 20-30 kg/m² and hemoglobin A1c (HbA1c) of 6-8% were enrolled. Patients were randomly assigned to receive 450 mg of aqueous R. ribes extract (AG), 450 mg of ethanolic R. ribes extract (EG), or placebo (PG) three times daily for 6 weeks. At the baseline and at the end of the study, blood glucose levels, homeostatic model assessment of insulin resistance (HOMA-IR) and the homeostatic model assessment of β-cell dysfunction (HOMA-B), as well as apolipoprotein A-I (ApoA1) and apolipoprotein B (ApoB) were measured.

RESULTS

There was a significant decrease in the serum levels of insulin in AG and EG groups (P = 0.003 and P = 0.001, respectively), HOMA-IR (P = 0.01 and P = 0.001, respectively), HOMA-B (P = 0.002 and P = 0.001, respectively), ApoB (P = 0.006 and P = 0.03, respectively), ApoB/ApoA1 ratio (P = 0.016 and P = 0.04, respectively). However, a significant increase in ApoA1 (P = 0.08 and P = 0.05, respectively) with no significant changes in blood glucose, at the end of study compared to beginning values, were observed. None of the variables showed a significant change in PG. At the end of the study; while there were significant differences in insulin (P = 0.04), HOMA-IR (P = 0.03), HOMA-B (P = 0.01), ApoB (P = 0.02), and ApoB/ApoA1 ratio (P = 0.03) among the groups but ApoA1 had no significant change.

CONCLUSION

Consumption of R. ribes intake could have beneficial effects on insulin resistance and apolipoproteins in type 2 diabetic patients. (Registered at en.irct.ir, identification number: IRCT201410142709N31).

Inulin increases the beneficial effects of rhubarb supplementation on high-fat high-sugar diet-induced metabolic disorders in mice: impact on energy expenditure, brown adipose tissue activity, and microbiota

Consumption of prebiotics and plant-based compounds have many beneficial health effects through modulation of gut microbiota composition and are considered as promising nutritional strategy for the treatment of metabolic diseases. In the present study, we assessed the separated and combined effects of inulin and rhubarb on diet-induced metabolic disease in mice. We showed that supplementation with both inulin and rhubarb abolished the total body and fat mass gain upon high-fat and high-sucrose diet (HFHS) as well as several obesity-associated metabolic disorders. These effects were associated with increased energy expenditure, lower whitening of the brown adipose tissue, higher mitochondria activity and increased expression of lipolytic markers in white adipose tissue. Despite modifications of intestinal gut microbiota and bile acid compositions by inulin or rhubarb alone, combination of both inulin and rhubarb had minor additional impact on these parameters. However, the combination of inulin and rhubarb increased the expression of several antimicrobial peptides and higher goblet cell numbers, thereby suggesting a reinforcement of the gut barrier. Together, these results suggest that the combination of inulin and rhubarb in mice potentiates beneficial effects of separated rhubarb and inulin on HFHS-related metabolic disease and could be considered as nutritional strategy for the prevention and treatment of obesity and related pathologies.

Antioxidant Activities of Bioactive Compounds Isolated from Rheum emodi Wall (Himalayan Rhubarb) Based on LC-DAD-ESI/MS and Preparative LC/MS System

Natural compounds are a good substitute for synthetic antioxidants. Attempts have been made to characterize the antioxidant capacity of natural resources (e.g., medicinal plants). Thus, the Rheum emodi Wall was evaluated using liquid chromatography with diode array detection and electrospray ionization-mass spectrometry. Three antioxidant compounds (i.e., myricitrin, myricetin-3-galloyl rhamnoside, and myricetin) were isolated, identified, and used to screen the antioxidant capacity of the new compounds. 2,2-Diphenyl-1-picrylhydrazyl, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and superoxide dismutase assay results are presented in the half-maximal inhibitory concentration values ranging 1.50∼28.46, 102.01∼137.55, and 4.06∼15.74 μg/mL, respectively. Myricetin had the highest antioxidant activity among the other compounds. A significantly positive correlation was noted between the ethyl acetate fraction and the antioxidant compound. In a partial least squares-discriminant analysis model, identified antioxidant compounds were shown to play a role in the structure of the compound and its contents based on the antioxidant activity. The study suggests that myricetin from R. emodi possesses the most potent antioxidant activity, and thus is the most efficient in extracting antioxidant contents.

Magnetic Molecularly Imprinted Polymers: An Update on Their Use in the Separation of Active Compounds from Natural Products

During the last few years, separation techniques using molecularly imprinted polymers (MIPs) have been developed, making breakthroughs using magnetic properties. Compared to conventional MIPs, magnetic molecularly imprinted polymers (MMIPs) have advantages in sample pretreatment due to their high specificity and selectivity towards analytes as a result of their larger specific surface areas and highly accessible specific binding sites. The techniques of isolation of active compounds from natural products usually require very long process times and low compound yields. When MMIPs are used in sample separation as Solid Phase Extraction (SPE) sorbents, the MMIPs are introduced into the dissolved sample and spread evenly, and they form bonds between the analyte and the MMIPs, which are then separated from the sample matrix using an external magnetic field. This process of separating analytes from the sample matrix makes the separation technique with MMIPs very simple and easy. This review discusses how to synthesize MMIPs, which factors must be considered in their synthesis, and their application in the separation of active compounds from natural products. MMIPs with magnetic core-shells made by co-precipitation can be a good choice for further development due to the high synthesis yield. Further optimization of the factors affecting the size and distribution of magnetic core-shell particles can obtain higher synthesis yields of MMIPs with higher adsorption capacity and selectivity. Thus, they can isolate target compounds from natural plants in high yields and purity.

Himalaquinones A-G, Angucyclinone-Derived Metabolites Produced by the Himalayan Isolate Streptomyces sp. PU-MM59

Himalaquinones A-G, seven new anthraquinone-derived metabolites, were obtained from the Himalayan-based Streptomyces sp. PU-MM59. The chemical structures of the new compounds were identified based on cumulative analyses of HRESIMS and NMR spectra. Himalaquinones A-F were determined to be unique anthraquinones that contained unusual C-4a 3-methylbut-3-enoic acid aromatic substitutions, while himalaquinone G was identified as a new 5,6-dihydrodiol-bearing angucyclinone. Comparative bioactivity assessment (antimicrobial, cancer cell line cytotoxicity, impact on 4E-BP1 phosphorylation, and effect on axolotl embryo tail regeneration) revealed cytotoxic landomycin and saquayamycin analogues to inhibit 4E-BP1p and inhibit regeneration. In contrast, himalaquinone G, while also cytotoxic and a regeneration inhibitor, did not affect 4E-BP1p status at the doses tested. As such, this work implicates a unique mechanism for himalaquinone G and possibly other 5,6-dihydrodiol-bearing angucyclinones.

Anticancer and immunomodulatory effect of rhaponticin on Benzo(a)Pyrene-induced lung carcinogenesis and induction of apoptosis in A549 cells

In worldwide, one of the most important cancer-related death is lung cancer. Also has the highest mortality rate between various cancer types. The count of lung cancer occurrence is increasing with an increased frequency by smoking. Proficient chemoprevention approaches are needed to prevent the occurrence of lung cancer. Therefore, the aim of this exploration is to determine the therapeutic impact on the immune modulatory effect of rhaponticin on lung tumorigenesis in vivo and in vitro cytotoxicity effect in A549 cells of human lung cancer. Lung cancer tumorigenesis in mice was challenged with benzo(a)pyrene (BaP) with 50 mg/kg bodyweight (b.wt) as oral administration for 6 weeks (two times/week). Rhaponticin were given orally 30 mg/kg b.wt (two times/week) in BaP induced mice from 12 weeks to 18 weeks. After treatment completes, the body weight was measured and then blood, lung tissue was collected for various parameters detection. The results evidenced that BaP induced mice decreased the bodyweight, increased lung weight, increased tumor markers (AHH, CEA and LDH), and increased the proinflammatory cytokines. The enzyme catalase, superoxide dismutase activity was decreased and increased lipid peroxidation in immune comprising cells compared with the control cells. Moreover, rhaponticin treatment improves in chemical assays and also the histopathological alteration of lung tissues. The present findings provide evidence about the therapeutic potentials of rhaponticin against BaP triggered lung tumorigenesis.

Ethnobotanical Uses, Phytochemistry and Pharmacology of Different Rheum Species (Polygonaceae): A Review

Today, there is an increased tendency to use herbal remedies. Rhubarb refers to several species of the genus Rheum L. in the Polygonaceae family. This species-rich genus is mainly distributed in Asian countries. Several medicinal effects have been attributed to the Rheum spp. in the traditional and modern medicine such as healing lungs, liver, kidney, womb and bladder diseases, cancer, diabetes, insect bites, relapsing fevers, diarrhea and constipation. Various in vitro, in vivo and clinical studies have investigated the therapeutic effect of extracts, fractions and pure compounds isolated from different species of this genus. Considering the positive findings, several pharmaceutical formulations containing rhubarb extract like capsules, drops, mouthwashes and different topical formulations are now present in the market. However, there are other traditional therapeutic effects of rhubarb that have not been studied yet and it is of great importance to perform confirmatory experiments or clinical investigations. The current review summarizes general information regarding botany, phytochemistry, ethnobotany and pharmacological aspects of Rheum spp. It is hoped that the present review could motivate subsequent research on the other medicinal properties of these plants that have been neglected until today.

Rhubarb Supplementation Prevents Diet-Induced Obesity and Diabetes in Association with Increased Akkermansia muciniphila in Mice

Obesity and obesity-related disorders, such as type 2 diabetes have been progressively increasing worldwide and treatments have failed to counteract their progression. Growing evidence have demonstrated that gut microbiota is associated with the incidence of these pathologies. Hence, the identification of new nutritional compounds, able to improve health through a modulation of gut microbiota, is gaining interest. In this context, the aim of this study was to investigate the gut-driving effects of rhubarb extract in a context of diet-induced obesity and diabetes. Eight weeks old C57BL6/J male mice were fed a control diet (CTRL), a high fat and high sucrose diet (HFHS) or a HFHS diet supplemented with 0.3% (g/g) of rhubarb extract for eight weeks. Rhubarb supplementation fully prevented HFHS-induced obesity, diabetes, visceral adiposity, adipose tissue inflammation and liver triglyceride accumulation, without any modification in food intake. By combining sequencing and qPCR methods, we found that all these effects were associated with a blooming of Akkermansia muciniphila, which is strongly correlated with increased expression of Reg3γ in the colon. Our data showed that rhubarb supplementation is sufficient to protect against metabolic disorders induced by a diet rich in lipid and carbohydrates in association with a reciprocal interaction between Akkermansia muciniphila and Reg3γ.

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.

Protective mechanism of rhubarb anthraquinone glycosides in rats with cerebral ischaemia-reperfusion injury: interactions between medicine and intestinal flora

Background

Anthraquinone glycosides extracted from rhubarb have been proven to have significant therapeutic effects on ischaemic stroke. It is well known that anthraquinone glycosides are not easily absorb. Thus, how can rhubarb anthraquinone glycosides (RAGs) exert protective effects on the brain? Is this protective effect related to interactions between RAGs and intestinal flora?

Methods

The model used in this study was established by middle cerebral artery occlusion (MCAO) and reperfusion. Twenty-seven adult male Sprague–Dawley (SD) rats were randomly divided into 3 groups: the normal group (A) (non-MCAO + 0.5% sodium carboxymethyl cellulose (CMC-Na)), model group (B) (MCAO + 0.5% CMC-Na) and medicine group (C) (MCAO + RAGs (15 mg/(kg day)). The rats were fed by gavage once a day for 7 days. Fresh faeces were collected from the normal group to prepare the intestinal flora incubation liquid. Add RAGs, detect the RAGs and the corresponding anthraquinone aglycones by HPLC–UV at different time points. On the 8th day, the rats were euthanized, and the colonic contents were collected and analysed by high-throughput sequencing. In addition, 12 adult male SD rats were randomly divided into 2 groups: the normal group (D) (non-MCAO + RAGs (15 mg/(kg day)) and model group (E) (MCAO + RAGs (15 mg/(kg day)). The rats were fed by gavage immediately after reperfusion. Blood was collected from the orbital venous plexus, and the RAGs and anthraquinone aglycones were detected by HPLC–UV.

Results

The abundance and diversity of the intestinal flora in rats decreased after cerebral ischaemia–reperfusion injury (CIRI). RAGs could effectively improve the abundance of the intestinal flora. In addition, in vitro metabolism studies showed that RAGs were converted into anthraquinone aglycones by intestinal flora. In the in vivo metabolism studies, RAGs could not be detected in the plasma; in contrast, the corresponding anthraquinone aglycones could be detected. Absorption of RAGs may be inhibited in rats with CIRI.

Conclusions

CIRI may lead to intestinal flora disorder in rats, and after the administration of RAGs, the abundance of intestinal flora can be improved. RAGs can be metabolized into their corresponding anthraquinone aglycones by intestinal flora so that they can be absorbed into the blood.

Micropropagation, Genetic Fidelity and Phenolic Compound Production of Rheum rhabarbarum L

An efficient micropropagation protocol for Rheum rhabarbarum L. was developed in this study. The in vitro rhubarb plants obtained in the multiplication stage (proliferation rate: 5.0 ± 0.5) were rooted in vitro (96% rooting percentage) and acclimatized ex vitro in floating perlite, with 90% acclimatization percentage. To assess the genetic fidelity between the mother plant and in vitro propagated plants, sequence-related amplified polymorphism (SRAP) markers were used. All banding profiles from the micropropagated plants were monomorphic and similar to those of the mother plant indicating 100% similarity. Regarding the polyphenolic profile, gallic, protocatechuic, p-hydroxybenzoic, vanillic, chlorogenic, caffeic, syringic, p-coumaric and ferulic acid were present in different amounts (2.3-2690.3 μg g^-1 dry plant), according to the extracted matrix. Aglicons and glycosides of different classes of flavonoids were also identified. The rhizome extracts (both from in vitro and field grown plants) contained resveratrol, a stilbene compound with high antioxidant properties, ranging between 229.4 to 371.7 μg g^-1 plant. Our results suggest that in vitro propagation of Rheum rhabarbarum L. represents a reliable alternative to obtain a large number of true-to-type planting material with high bioactive compound content of this valuable nutritional and medicinal species.

Antimicrobial and Antioxidative Effects of Plant Powders in Raw and Cooked Minced Pork

It is a challenge for scientists to find new plant-based food constituents simultaneously possessing antimicrobial and antioxidative properties to prolong the shelf life of meat products. In this study, various plant powders and their blends were added to minced pork to carry out a complex study of their effect on sensory characteristics, microbial growth, and lipid oxidation of the meat in raw and cooked forms during storage. Microbiological shelf life parameters were evaluated by determining the total counts of microorganisms, yeasts, and molds. The growth potential of Listeria monocytogenes was estimated by challenge testing. The impact on lipid oxidation processes was assessed using thiobarbituric acid reactive substances (TBARS) and high performance liquid chromatography (HPLC) methods. The results showed that the blend of rhubarb petioles and tomato powder added a pleasant color and a combined taste to the product, similar to the taste of salt. In raw samples, considerable microbial growth inhibition was achieved with rhubarb petioles, tomato, and their mixture. Nine treatments of cooked samples had a stronger inhibitory effect on microbial growth compared to control treatments. Among all plant powders, tomato was the most effective inhibitor of yeast and mold growth. However, the challenge test revealed that L. monocytogenes growth in cooked samples was not inhibited during shelf life. In raw samples, rhubarb roots combined with blackcurrant or chokeberry berries effectively inhibited lipid oxidation, and in cooked samples, rhubarb petioles showed a similar effect. In conclusion, it was found that powdered plant materials are well suited for use as antimicrobial and antioxidative agents in minced meat products.

Efficacy of traditional Chinese medication Tangminling pill in Chinese patients with type 2 diabetes

The morbidity of type 2 diabetes mellitus (T2DM) has been increasing rapidly worldwide. Tangminling pill, consisting of ten Chinese herbal medications, is usually prescribed for T2DM in mainland China. Whether treatment with Tangminling can improve clinical outcomes of T2DM patients was still debated. Four studies comparing Tangminling vs. placebo treatment in T2DM patients were included and 767 T2DM patients were enrolled in our analyses. Tangminling treatment exhibited better efficacy than placebo in reducing hemoglobin A1c (HbA1c) (1.11 vs. 0.32%; pooled weighted mean difference [WMD]: 0.80; 95% confidence interval [CI]: 0.65–0.96; P<0.001), fasting plasma glucose (0.82 vs. −0.40 mM; WMD: 1.10; 95% CI: 0.56–1.64; P<0.001), 2-h postprandial glucose (2-hr PG) (2.81 vs. 1.11 mM; WMD: 1.80; 95% CI: 1.72–1.88; P<0.001), homeostatic model assessment-β level (4.28 vs. 0.41; WMD: 0.44; 95% CI: 0.27–0.61; P<0.001), waist circumference (WC) (1.04 vs. 0.36 cm; WMD: 0.78; 95% CI: 0.37–1.19; P<0.001) and body weight index (0.37 vs. 0.11 kg/m²; WMD: 0.30; 95% CI: −0.00 to 0.61; P=0.05). Tangminling pill might reduce glucose level and body weight and improve β-cell function in T2DM patients. Our study highlights the important role of Tangminling pill in the management of T2DM.

Rhaponticin decreases the metastatic and angiogenic abilities of cancer cells via suppression of the HIF‑1α pathway

Rhaponticin (RA; 3′5-dihydroxy-4′-methoxystilbene 3-O-β-D-glucopyranoside) is a component isolated from various medicinal herbs including Rheum undulatum L. RA has been reported to be an effective treatment for allergy, diabetes, thrombosis, liver steatosis, lung fibrosis and colitis. In addition, RA effectively inhibits tumor growth and induces apoptosis; however, the effects of RA, at non-cytotoxic doses, on the metastasis and angiogenesis of malignant cancer cells have, to be the best of our knowledge, not been identified. In the present study, it was identified that RA suppressed the metastatic potential of MDA-MB231 breast cancer cells, including colony formation, migration and invasion. Human umbilical vein endothelial cells (HUVECs) treated with RA exhibited a decreased ability to form tube-like networks and to migrate across a Transwell membrane, when compared with RA-untreated HUVECs. Using the chick chorioallantoic membrane assay, RA treatment significantly suppressed spontaneous and vascular endothelial growth factor (VEGF)-induced angiogenesis. Furthermore, RA inhibited the production of pro-angiogenic factors, including matrix metalloproteinase (MMP)-9, pentraxin-3, interleukin-8, VEGF and placental growth factor under normoxic and hypoxic conditions, and suppressed the phorbol 12-myristate 13-acetate-induced increase in the gelatinolytic MMP-9 activity and MMP-9 expression in HT1080 cells. RA also significantly inhibited the hypoxia-inducible factor (HIF)-1α pathway, leading to decreased HIF-1α accumulation and HIF-1α nuclear expression under hypoxia. These results indicated that RA exhibits potent anti-metastatic and anti-angiogenic activities with no cytotoxicity via suppression of the HIF-1α signaling pathway. Thus, RA may control malignant cancer cells by inhibiting the spread from primary tumors and expansion to distant organs.

Lipid Peroxidation and Antioxidant Activities of the Aqueous Rhizome Extract of Rheum officinale Baillon

Generation of reactive oxygen species (ROS) is associated with dysregulation of antioxidant defense mechanisms and incidence of human diseases. The specific aim of this study was to investigate the lipid oxidation and antioxidant activity of aqueous extract of Rheum officinale Baillon rhizome in order to evaluate its potential as a future novel natural antioxidant resource and a functional ingredient in food and pharmaceutical formations. Total phenolic and flavonoid contents of Rheum rhizome extract were dose dependently increased. Consistent with this, radical scavenging activities of Rheum rhizome extract as determined by 2,2-diphenyl-1-picrylhydrazyl assay and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity were significantly elevated as the concentration increased. In addition, the treatment of aqueous Rheum rhizome extract significantly increased ferric reducing and copper chelating activities. According to results of thiobarbituric acid reactive substance analysis, Rheum rhizome extract significantly delayed lipid oxidation. Preincubation with Rheum rhizome extract significantly inhibited tert-butyl hydroperoxide- (t-BHP-) induced ROS generation. Moreover, superoxide anion production was significantly lower in Rheum rhizome extract-treated RAW264.7 macrophage cells than t-BHP-incubated cells (p<0.05). These findings suggest that Rheum officinale Baillon rhizome extract has a potential as an excellent natural antioxidant agent.

Desoxyrhapontigenin inhibits RANKL‑induced osteoclast formation and prevents inflammation‑mediated bone loss

Desoxyrhapontigenin (DRG), a stilbene compound from Rheum undulatum, has been found to exhibit various pharmacological activities, however, its impact on osteoclast formation has not been investigated. The present study investigated the effect of DRG on receptor activator of nuclear factor‑κB ligand (RANKL)‑induced osteoclast differentiation in mouse bone marrow macrophages (BMMs) and inflammation‑induced bone loss in vivo. BMMs or RAW264.7 cells were treated with DRG, followed by an evaluation of cell viability, RANKL‑induced osteoclast differentiation, actin‑ring formation and resorption pits activity. The effects of DRG on the RANKL‑induced phosphorylation of MAPK and the expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and c‑Fos were evaluated using western blot analysis once the BMMs were exposed to RANKL and DRG. The expression levels of osteoclast marker genes were also evaluated using western blot analysis and reverse transcription‑quantitative polymerase chain reaction A lipopolysaccharide (LPS)‑induced murine bone loss model was used to evaluate the protective effect of DRG on inflammation‑induced bone‑loss. The results demonstrated that DRG suppressed the RANKL‑induced differentiation of BMMs into osteoclasts, osteoclast actin‑ring formation and bone resorption activity in a dose‑dependent manner. Furthermore, DRG significantly inhibited LPS‑induced bone loss in a mouse model. At the molecular level, DRG inhibited the RANKL‑induced activation of extracellular signal‑regulated kinase, the expression of c‑Fos, and the induction of NFATc1, a crucial transcription factor for osteoclast formation. DRG decreased the expression levels of osteoclast marker genes, including matrix metalloproteinase‑9, tartrate‑resistant acid phosphatase and cathepsin K. In conclusion, these findings suggested that DRG inhibited the differentiation of BMMs into mature osteoclasts by suppressing the RANKL‑induced activator protein‑1 and NFATc1 signaling pathways, and may be a potential candidate for treating and/or preventing osteoclast‑associated diseases, including osteoporosis.

Estrogenic activity of constituents from the rhizomes of Rheum undulatum Linné

Stilbenes have been reported to be phytoestrogen compounds owing to its structural similarity to the estrogenic agent diethylstilbestrol. To find new stilbene-derivative phytoestrogens, isolation of stilbene-rich R. undulatum was performed and led to identify six new compounds (1-5 and 28), one newly determined absolute configurations compound (27) together with 21 previously reported compounds (6-26). The structures of compounds were determined on the basis of extensive spectroscopic methods including 1D and 2D NMR and CD spectra data. All the isolated compounds were tested for their estrogenic activities in HepG2 cells transiently transfected with ERα, ERβ and ERE-reporter plasmid. Among them, stilbene-derivatives, piceatannol 3'-O-β-d-xylopyranoside (12), cis-rhaponticin (16) and rhapontigenin 3'-O-β-d-glucopyranoside (17), showed the more potent binding affinity for estrogen receptors than 17β-estrodiol.

Valorisation of softwood bark through extraction of utilizable chemicals. A review

Softwood bark is an important source for producing chemicals and materials as well as bioenergy. Extraction is regarded as a key technology for obtaining chemicals in general, and valorizing bark as a source of such chemicals in particular. In this paper, properties of 237 compounds identified in various studies dealing with extraction of softwood bark were described. Finally, some challenges and perspectives on the production of chemicals from bark are discussed.

Visualizing spatial distribution of small molecules in the rhubarb stalk (Rheum rhabarbarum) by surface-transfer mass spectrometry imaging

Laser desorption/ionization mass spectrometry imaging (LDI-MSI) with gold nanoparticle-enhanced target (AuNPET) was used for visualization of small molecules in the rhubarb stalk (Rheum rhabarbarum L.). Analysis was focused on spatial distribution of biologically active compounds which are found in rhubarb species. Detected compounds belong to a very wide range of chemical compound classes such as anthraquinone derivatives and their glucosides, stilbenes, anthocyanins, flavonoids, polyphenols, organic acids, chromenes, chromanones, chromone glycosides and vitamins. The analysis of the spatial distribution of these compounds in rhubarb stalk with the nanoparticle-rich surface of AuNPET target plate has been made without additional matrix and with minimal sample preparation steps.

Synthetic approaches toward stilbenes and their related structures

Compounds belonging to the stilbene family have gained remarkable significance in pharmaceutical as well as material chemistry. The current review covers the various synthetic approaches for the syntheses of stilbene scaffold and related structures over last 30 years. In addition, this review also highlights the role of stilbene intermediates used in the synthesis of important molecules with diverse applications in the field of pharmaceutics and material science.

Strategies to promote abundance of Akkermansia muciniphila, an emerging probiotics in the gut, evidence from dietary intervention studies

Akkermansia muciniphila is a mucin-degrading bacterium commonly found in human gut. A. muciniphila has been inversely associated with obesity, diabetes, inflammation, and metabolic disorders. Due to its highly promising probiotic activities against obesity and diabetes, A. muciniphila has drawn intensive interest for research and development in recent years. A number of human and animal studies have shown that the abundance of A. muciniphila in the gut can be enhanced through dietary interventions. The present review focuses on evidence-based dietary strategies of improving A. muciniphila abundance in the gut by critically appraising up-to-date available human and animal intervention studies on A. muciniphila growth and their impact on risk factors of obesity and diabetes. Their potential mechanisms in promoting A. muciniphila are also discussed along with the discussions of mechanism of action for A. muciniphila to exert probiotic functions.

A Theoretical Study on the Antioxidant Activity of Piceatannol and Isorhapontigenin Scavenging Nitric Oxide and Nitrogen Dioxide Radicals

The antioxidant activity of naturally occurring stilbene compounds piceatannol (PIC) and isorhapontigenin (ISO) scavenging two free radicals (NO and NO₂) were studied using density functional theory (DFT) method. Four reaction mechanisms have been considered: hydrogen atom transfer (HAT), radical adduct formation (RAF), single electron transfer (SET), and sequential proton loss electron transfer (SPLET). The reaction channels in water solution were traced independently, and the respective thermodynamic and kinetic parameters were obtained. We found PIC and ISO scavenge NO mainly through RAF mechanism, and scavenge NO₂ through HAT mechanism. The capacity of PIC scavenging NO₂ is much higher than ISO, but the reactivity of scavenging NO is lower than ISO.

Add-on effect of crude rhubarb to somatostatin for acute pancreatitis: A meta-analysis of randomized controlled trials

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb is one of the common herbs used in traditional Chinese complex prescriptions for the treatment of various inflammatory diseases. We sought to determine the add-on effect of crude rhubarb to somatostatin in patients with acute pancreatitis by conducting a meta-analysis.

MATERIALS AND METHODS

We searched the Pubmed, EMBASE, Cochrane Library, CNKI, Wanfang, VIP databases up to November 2015. Randomized controlled trials (RCTs) comparing crude rhubarb plus somatostatin to somatostatin alone for acute pancreatitis were included. Risk ratio (RR) or weighted mean difference (WMD) with their 95% confidence interval (CI) was calculated between with and without crude rhubarb therapy.

RESULTS

A total of 19 RCTs involving 1161 patients were identified. Compared with somatostatin alone, crude rhubarb plus somatostatin significantly reduced the total complications (RR 0.55; 95% CI 0.41-0.73) and APACHE Ⅱ scores (WMD -1.16; 95% CI -1.91 to -0.41) as well as shortened the duration of elevated serum amylase (WMD -2.01 days; 95% CI -2.57 to -1.44), duration of abdominal pain (WMD -1.33 days; 95% CI -1.61 to -1.05), the first defecation time (WMD -2.27 days; 95% CI -3.06 to -1.47), and duration of hospital stay (WMD -6.70 days; 95% CI -8.81 to -4.60). However, there were no significant differences in total mortality rates (RR 0.61; 95% CI 0.34 to 1.12) between two groups.

CONCLUSIONS

Crude rhubarb as adjuvant therapy to somatostatin appears to have additional benefits in patients with acute pancreatitis. However, interpretation of these results should be cautioned due to the methodological flaws.

Intravenous administration of piceatannol, an arginase inhibitor, improves endothelial dysfunction in aged mice

Advanced age is one of the risk factors for vascular diseases that are mainly caused by impaired nitric oxide (NO) production. It has been demonstrated that endothelial arginase constrains the activity of endothelial nitric oxide synthase (eNOS) and limits NO generation. Hence, arginase inhibition is suggested to be vasoprotective in aging. In this study, we examined the effects of intravenous injection of Piceatannol, an arginase inhibitor, on aged mice. Our results show that Piceatannol administration reduced the blood pressure in aged mice by inhibiting arginase activity, which was associated with NO production and reactive oxygen species generation. In addition, Piceatannol administration recovered Ca²⁺/calmodulin-dependent protein kinase II phosphorylation, eNOS phosphorylation and eNOS dimer stability in the aged mice. The improved NO signaling was shown to be effective in attenuating the phenylephrine-dependent contractile response and in enhancing the acetylcholine-dependent vasorelaxation response in aortic rings from the aged mice. These data suggest Piceatannol as a potential treatment for vascular disease.

Degranulation Inhibitors from Medicinal Plants in Antigen-Stimulated Rat Basophilic Leukemia (RBL-2H3) Cells

Mast cells and basophils play important roles in both immediate- and late-phase reactions of type 1 allergy. Histamine, which is released from mast cells and basophils stimulated by an antigen or degranulation inducers, is usually determined as a degranulation marker in experiments on immediate allergic reactions in vitro. β-Hexosaminidase is also stored in secretory granules of the cells and is released concomitantly with histamine when the cells are immunologically activated, and recently this enzyme activity in the medium has been used as a marker of the degranulation. In this paper, we review our studies on the search for degranulation inhibitors, such as flavonoids, stilbenes, and curcuminoids, from medicinal plants using rat basophilic leukemia (RBL-2H3) cells.

Separation of three anthraquinone glycosides including two isomers by preparative high-performance liquid chromatography and high-speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf

Anthraquinone glycosides, such as chrysophanol 1-O-β-d-glucoside, chrysophanol 8-O-β-d-glucoside, and physion 8-O-β-d-glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above-mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1-O-β-d-glucoside and chrysophanol 8-O-β-d-glucoside. This study demonstrated an efficient strategy based on preparative high-performance liquid chromatography and high-speed countercurrent chromatography for the separation of the above-mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf.

Improved Quantification of Free and Ester-Bound Gallic Acid in Foods and Beverages by UHPLC-MS/MS

Hydrolyzable tannins are measured routinely during the characterization of food and beverage samples. Most methods for the determination of hydrolyzable tannins use hydrolysis or methanolysis to convert complex tannins to small molecules (gallic acid, methyl gallate, and ellagic acid) for quantification by HPLC-UV. Often unrecognized, analytical limitations and variability inherent in these approaches for the measurement of hydrolyzable tannins include the variable mass fraction (0-0.90) that is released as analyte, contributions of sources other than tannins to hydrolyzable gallate (can exceed >10 wt %/wt), the measurement of both free and total analyte, and lack of controls to account for degradation. An accurate, specific, sensitive, and higher-throughput approach for the determination of hydrolyzable gallate based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) that overcomes these limitations was developed.

Adjuvant treatment with crude rhubarb for patients with acute organophosphorus pesticide poisoning: A meta-analysis of randomized controlled trials

BACKGROUND

Crude rhubarb has been used to treat critically ill patients for many years. However, no previous meta-analysis has been investigated the benefits of crude rhubarb in patients with acute organophosphorus pesticide poisoning (AOPP).

OBJECTIVE

To summarize the beneficial effects of adjuvant treatment with crude rhubarb in patients with AOPP by conducting a meta-analysis.

METHODS

A literature search of the databases through Pubmed, EMBASE, China National Knowledge Infrastructure, VIP, and Wanfang were performed for studies published up to October 2014. Randomized controlled trials (RCTs) investigating the effects of crude rhubarb as adjuvant treatment for patients with AOPP were included.

RESULTS

A total of 12 RCTs with 886 patients were identified. Adjuvant treatment with crude rhubarb was associated with a significantly lower incidence of intermediate syndrome (risk ratio [RR] 0.22; 95% confidence interval [CI] 0.10-0.48), as well as multiple organ dysfunction syndrome (RR 0.34; 95% CI 0.20-0.56). Crude rhubarb as adjuvant treatment reduced the total dose of pralidoxime (mean difference [MD] -5.12 g; 95% CI -8.24 to -2.00) or atropine (MD -94.89 mg; 95% CI -156.22 to -33.57), and hospital length of stay (MD -2.79 days; 95% CI -4.19 to -1.39) compared with the controls.

CONCLUSIONS

This meta-analysis suggests that crude rhubarb as adjuvant treatment appears to have additional beneficial effects in patients with AOPP. More well-designed trials are needed to confirm our findings due to the methodological flaws of the included trials.

Toxic Effects of Rhamnus alaternus: A Rare Case Report

In Tunisia, there are about 478 species of plants commonly used in folk medicine. Medicinal plants and herbal remedies used are responsible for 2% of intoxications listed by Tunisian National Poison Center. Most cases are related to confusion between edible plants and toxic plants lookalikes or to an excessive consumption of therapeutic plants. We report the case of a 58-year-old man admitted to the Emergency Department of the Regional Hospital of Zaghouan (Tunisia), with renal failure and rhabdomyolysis. The patient reported having daily consumption of a homemade tea based on Mediterranean Buckthorn roots, during the last 6 months to treat type 2 diabetes. The aim of this work was to establish an association between the consumption of the herbal remedy and the occurrence of both renal failure and rhabdomyolysis. No similar cases have been reported in recent literature.

The multi-targets integrated fingerprinting for screening anti-diabetic compounds from a Chinese medicine Jinqi Jiangtang Tablet

ETHNOPHARMACOLOGICAL RELEVANCE

Jinqi Jiangtang Tablet is a traditional Chinese anti-diabetic formula containing three ingredients: Coptis chinensis Franch. (dried rhizome of C. chinensis Franch., Coptis deltoidea C. Y. Cheng et Hsiao and Coptis teeta Wall.), Astragalus membranaceus (Fisch.) Bunge. (dried root of A. membranaceus (Fisch.) Bge. var. mongholicus (Bge. ) Hsiao and A. membranaceus (Fisch.) Bge. ) and Lonicera japonica Thunb. (dried alabastrum or with nascent flowers of L. japonica Thunb. ). Free radicals, α-glucosidase, α-amylase, aldose reductase and lipase are different targets related with diabetes. However, there are no chromatographic methods employed in screening the anti-diabetic compounds from natural products basing on these targets simultaneously. The present study was aimed at the establishment of a multi-targets integrated fingerprinting to clarify the possible mechanism of the action of Traditional Chinese Medicines which simultaneously contained multiple chemical characteristics and effects of constitutions.

MATERIALS AND METHODS

The multi-targets integrated fingerprinting was developed and validated to screen anti-diabetic compounds from natural products by using ultra-high-performance liquid chromatography/quadruple-time-of-flight mass spectrometry, fraction collector and microplate reader. Ultra performance liquid chromatography was employed to separate the components in Jinqi Jiangtang Tablet, which were identified by quadruple-time-of-flight mass spectrometry to acquire their structural information and collected by the fraction collector. Finally the active fractions were tested for scavenging 1, 1-diphenyl-2-picrylhydrazyl radical and inhibition of α-glucosidase, α-amylase, aldose reductase, and lipase activities in vitro by microplate reader.

RESULTS

Our tests revealed that the Jinqi Jiangtang Tablet showed inhibitory activity against α-glucosidase, α-amylase, aldose reductase and lipase with IC50 values of 0.80 ± 0.02 mg/mL, 1.28 ± 0.13 mg/mL, 0.80 ± 0.02 mg/mL, 1.90 ± 0.18 mg/mL respectively and the scavenging activity with IC50 value of 1.71 ± 0.178 mg/mL. The bioactive fractions were identified to be alkaloids, flavonoids and phenolic acids. The phenolic acids possessed antioxidant activities, namely the scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl rull;). The alkaloids exhibited inhibitory activity against α-glucosidase, aldose reductase, α-amylase, and lipase. The flavonoids also showed mild inhibition on α-glucosidase, aldose reductase, α-amylase and lipase.

CONCLUSIONS

The results demonstrate that Jinqi Jiangtang Tablet can scavenge free radicals and inhibit α-glucosidase, aldose reductase, α-amylase and lipase, which may be the possible mechanism of action of Jinqi Jiangtang Tablet for the treatment of diabetes and associated complications. Compared with conventional chromatographic separation and activity assays, the multi-targets integrated fingerprinting, which simultaneously contains the chemical characteristics and multiple effects of constitutions could comprehensively and properly reveal the activity of Jinqi Jiangtang Tablet. The results also show that the multi-targets integrated fingerprinting is a novel and powerful tool for screening and identifying active ingredients from Traditional Chinese Medicines.

Adjuvant treatment with crude rhubarb for patients with systemic inflammation reaction syndrome/sepsis: a meta-analysis of randomized controlled trials

OBJECTIVE

The objective of this study is to evaluate the benefits of adjuvant treatment with crude rhubarb in patients with systemic inflammation reaction syndrome/sepsis by conducting a meta-analysis.

METHODS

We conducted a systematic literature search of medical electronic databases (up to October 2013). Only randomized controlled trials (RCTs) assessing adjuvant treatment with crude rhubarb in septic patients were included.

RESULTS

A total of 15 RCTs with 869 patients were identified. Pooled analysis showed that interleukin 6 (standardized mean differences [SMDs], -1.30; 95% confidence intervals [CIs], -1.94 to -0.66), tumor necrosis factor α (SMD, -0.95; 95% CI, -1.55 to -0.36), procalcitonin (SMD, -1.50; 95% CI, -2.20 to -0.80), von Willebrand factor (mean differences [MDs], -144.11; 95% CI, -253.87 to -34.35), prothrombin time (MD, -2.38; 95% CI, -2.67 to -2.10), acute physiology and chronic health evaluation II scores (MD, -4.51; 95% CI, -5.30 to -3.73), and gastrointestinal dysfunction (risk ratio, 0.28; 95% CI, 0.16-0.49) were significantly reduced after treatment with crude rhubarb. Platelet number (MD, 58.16; 95% CI, 51.16-65.15) was significantly increased. However, crude rhubarb therapy did not significantly reduce 28-day mortality (risk ratio, 0.60; 95% CI, 0.36-1.00) compared with the usual treatment.

CONCLUSIONS

Adjuvant treatment with crude rhubarb appears to have additional benefits in septic patients. Antiinflammation and anticoagulant/antiaggregant properties may be its potential mechanism.

An unusual piceatannol dimer from Rheum austral D. Don with antioxidant activity

A novel dimer of piceatannol glycoside, named rheumaustralin (1) was isolated from the underground parts of the ethnomedicinal plant Rheum austral (Polygonaceae) collected from Tibet together with 17 known compounds, including rheumin (2), 2,5-dimethyl-7-hydroxychromone (3), 2,5-dimethylchromone-7-O-β-D-glucopyranoside (4), 7-hydroxy-2-(2'-hydroxypropyl)-5-methylchromone (5), torachrysone (6) torachrysone-8-O-β-D-glucopyranoside (7), 4-(4'-hydroxyphenyl)-2-butanone-4'-O-β-D-glucopyranoside (8), amabiloside (9), N-trans-feruloyl tyramine (10), chrysophanol (11), aloe-emodin (12), emodin (13), physcion (14), physcion-1-O-β-D-glucopyranoside (15), emodin-8-O-β-D-glucopyranoside (16), D-catechin (17) and gallic acid (18). Their structures were determined by combined spectroscopic methods and by comparison of their spectral data with those reported in literature. Compounds 1-10 were tested for their ability to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical.

Inhibition of cancer derived cell lines proliferation by synthesized hydroxylated stilbenes and new ferrocenyl-stilbene analogs. Comparison with resveratrol

Further advances in understanding the mechanism of action of resveratrol and its application require new analogs to identify the structural determinants for the cell proliferation inhibition potency. Therefore, we synthesized new trans-resveratrol derivatives by using the Wittig and Heck methods, thus modifying the hydroxylation and methoxylation patterns of the parent molecule. Moreover, we also synthesized new ferrocenylstilbene analogs by using an original protective group in the Wittig procedure. By performing cell proliferation assays we observed that the resveratrol derivatives show inhibition on the human colorectal tumor SW480 cell line. On the other hand, cell viability/cytotoxicity assays showed a weaker effects on the human hepatoblastoma HepG2 cell line. Importantly, the lack of effect on non-tumor cells (IEC18 intestinal epithelium cells) demonstrates the selectivity of these molecules for cancer cells. Here, we show that the numbers and positions of hydroxy and methoxy groups are crucial for the inhibition efficacy. In addition, the presence of at least one phenolic group is essential for the antitumoral activity. Moreover, in the series of ferrocenylstilbene analogs, the presence of a hidden phenolic function allows for a better solubilization in the cellular environment and significantly increases the antitumoral activity.

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.