Rhubarb Extract Research Articles

Solid phase adsorption of anthraquinones from plant extracts by lamellar solids

Solid phase extraction is nowadays a well validated and powerful technique applicable to complex matrices like plant extracts and phytocomplexes. This process provides concentration and/or purification of selected secondary metabolites from these matrices for subsequent analysis and isolation. In this research article sixteen lamellar solids, comprising layered structures (hydrotalcites, zirconium phosphates, magnesium hydroxide), magnesium oxide, and the phyllosilicates talc and bentonite were investigated for their capacity and performance to selectively adsorb five naturally occurring and widespread anthraquinones (aloe, aloe-emodin, rhein, chrysophanol, and physcion) contained in three ethanolic extracts of well known plants with purgative effects (frangula, senna, and rhubarb). Ethanolic solutions of extracts from these species were vigorously magnetically stirred with fixed quantities of each solid support at room temperature for 1 h. Subsequent HPLC analysis, coupled to photodiode array detection, revealed that, among the solids tested, the hydrotalcite zinc aluminum oleate and magnesium aluminum azelate and magnesium oxide were largely the most effective to this concern allowing to recover anthraquinones (all or some) in good to excellent percentages. Another interesting result was the selective and total removal of rhein by some sorbents from senna and rhubarb extracts. Sorbents were also recyclable and could be re-used to accomplish additional steps without appreciable loss of adsorption capacity. The application of the title solid inorganic and mixed inorganic/organic supports for the selective adsorption and concentration in the solid phase of anthraquinones from commonly used laxative plant species is reported herein for the first time.

Allelopathic effect of rhubarb extracts on the growth of Microcystis aeruginosa.

With its advantages of ecological safety, environmental affinity, and high selectivity, allelopathic technology has been widely developed for algae inhibition. However, obtaining effective allelochemicals and realizing their mechanism are difficult. In this paper, a Chinese herbal medicine, namely, Rheum palmatum L. (Chinese rhubarb), was utilized as a source of allelopathic substances for the first time. Four units of rhubarb organic extracts were collected to study the inhibition of growth, photosynthesis, proteins, and algal toxin of Microcystis aeruginosa. Results showed that the ethyl acetate, n-butanol, and aqueous phases of the rhubarb extracts have notable inhibitory effects. After a 16-day treatment, the four extracts reduced M. aeruginosa by 64.1%, 59.3%, 61.9%, and 7.2% with disruption of algal photosynthesis and protein synthesis and reduction of algal toxin.

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

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

Study on antipyretic effect of rhubarb on rats and its antipyretic ingredients

A combination of LC-MS technology and activity evaluation was used to identify the antipyretic ingredients in rhubarb. The rat model of fever was established with dried yeast and then was administered ethanol extract and different polar fractions of rhubarb. Next, the anal temperature of these rats was measured and recorded at 0.5, 1, 2, 3, 4 and 5 h after administration, and the inhibition rate of each part on the rise of body temperature was calculated. The inhibition rate is higher and the antipyretic effect is better. The chemical composition of the effective fraction was analyzed with UPLC-ESI-Orbitrap-MS/MS technology. Compared with the model group, the increase of body temperature of ethanol extract group all reduced at each measurement time especially after 3 h, and the inhibition rate were 38.7%(P<0.05), 78.2%(P<0.01) and 72.4%(P<0.01) at 3 h, 4 h, and 5 h after administration, respectively. Both n-butanol and water fraction showed some antipyretic activity in the early stage, with the inhibition rate of 28.1%(P<0.01) and 24.9%(P<0.05) at 1 h after administration, respectively, while other fractions were not active. Thirty-three and twelve compounds were identified from n-butanol and water fraction by LC-MS/MS analysis, respectively, including ten tannins, fifteen anthraquinone glycosides, four anthrone glycosides, one phenolic glycoside, one naphthaline derivative, one anthraquinone and one sucrose. These results revealed that rhubarb had antipyretic activity on rats, and tannin and anthraquinone glycosides were the main active ingredients inside.

Effect of different compatibility ratios of Centella asiatica-Rhubarb on the dissolution rate of effective components of Centella asiatica

Objective To study the effects of different compatibility ratios of Centella asiatica- Rhubarb on the dissolution rates of madecassoside and asiaticoside. Methods By using the HPLC method to analyze the content of madecassoside and asiaticoside in the Centella asiatica extract solution as well as Centella asiatica - Rhubarb extract solution with 6 different kinds of compatibility ratios. The tests were carried out by Thermo C18 (250 mm×4.6 mm, 5 μm) by isocratic elution with acetonitrile and 2 mmol/L of beta-cyclodextrin solution as mobile phase at a flow rate of 1 ml/min, the column temperature was 30 ℃ and the detection wavelength was 205 nm. Results Compared with the Centella asiatica extract solution, the dissolution rate of madecassoside decreased significantly with the increase of the proportion of rhubarb. The combination of Centella asiatica and Rhubarb had little effect on the content of asiaticoside. Conclusions Considering the clinical application and efficacy of Centella asiatica, the optimal ratio of Centella asiatica-Rhubarb is 10:1 and 15:1. Key words: Centellae herba; Rhei radix et rhizoma; Compatibility (TCD); Madecassoside; Asiaticoside; Assay (TCD)

Rhubarb-Evoke Mucus Secretion through Aggregation and Degranulation of Mast Cell in the Colon of Rat: In vivo and ex vivo studies

Rhubarb is commonly used to treat constipation in China for its function of promoting intestinal movement and optimum water content in feces. However, its mechanism of mucus secretion is vague. The aim of the study is to investigate the role of mast cells and enteric neurons in rhubarb extract (RE)-induced mucus secretion in the rat colon. Immunofluorescence was used to detect histamine receptors. Western blotting and 3,3′-diaminobenzidine (DAB) were applied to explore the content changes of mast cells activation. The changes in colonic goblet cells (GCs) were determined by means of PAS/AB staining. An intestinal perfusion system with a Bradford protein assay kit was directly to estimate in vitro secretion. And the cytokines were investigated with ELISA. The longitudinal aspect of this study indicate that the number and water content of faecal pellets were enhanced after the administration of different doses of RE accompanied by mast cells accumulated and increased the content of interferon (IFN) -γ or decreased the levels of interleukin (IL) −10 at doses of 3 and 6 g/kg. Pretreatment with ketotifen, mast cell stabilizer, had partially inhibited on RE-induced mucus secretion. Furthermore, RE induced the release of acetylcholine and mucin-2 in the colonic tissue and the histamine levels from the faeces. The results suggest that RE induced colonic mucus secretion involves mast cell activation and some cytokine.

Magnetic nanoparticles-based lactate dehydrogenase microreactor as a drug discovery tool for rapid screening inhibitors from natural products

Lactate dehydrogenase (LDH), catalyzing the conversion of pyruvate to lactate during glycolysis, is overexpressed in cancer cells. LDH inhibitors are a promising approach for the treatment of cancer. But up till now, there is limited method for rapid screening of LDH inhibitors. Herein, the use of LDH functionalized magnetic nanoparticles as a drug discovery tool for the selective enrichment of LDH potential inhibitors from natural products was firstly reported in this study. Firstly, LDH was immobilized onto the surface of amino-modified magnetic nanoparticles via covalent binding. In order to obtain the maximum enzyme activity, the immobilization conditions including pH, time and LDH concentration were optimized. The amount of LDH immobilized on MNPs was about 49 μg enzyme/mg carrier under the optimized conditions. Subsequently, the ligand fishing assay was performed to validate the specificity and selectivity of immobilized LDH using a model mixture, which consisted of galloflavin, chlorogenic acid and verbascoside. Finally, the immobilized LDH approach combined with ultra-high performance liquid chromatography-tandem mass spectrometry technique (UHPLC-MS/MS) was applied to screen potential LDH inhibitors from two anthraquinone-rich natural products (Rhubarb and Polygonum cuspidatum). Nine and six compounds were identified from Rhubarb and Polygonum cuspidatum extracts respectively, of which three compounds were common to both. Our results have proven that LDH functionalized magnetic nanoparticles have a significant prospect for drug discovery from complex matrices.

Antibacterial Effects of Hydro-alcoholic Extract of Pennyroyal, Cinnamon and Rhubarb on Klebsiella pneumoniae and Staphylococcus aureus: An In-vitro Study

Background: Medicinal plants have been used for many different purposes in the past. These plants may produce antimicrobial metabolites that affect the natural growth of microorganisms. The aim of this research was to study the antibacterial properties of rhubarb, cinnamon and pennyroyal on Staphylococcus aureus and Klebsiella pneumoniae.
 Materials and Methods: In this study, the effect of hydro-alcoholic extract of pennyroyal, cinnamon and rhubarb on Staphylococcus aureus and Klebsiella pneumoniae was investigated after their collection and extraction process. The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of this extract on bacteria were also measured.
 Results: The MIC of hydro alcoholic extract of pennyroyal was above 400 mg/ml for both Klebsiella pneumoniae and Staphylococcus aureus. Also the MBC has been reported 400 and 500 mg/dL, respectively. The MIC of cinnamon extract for Klebsiella pneumoniae and Staphylococcus aureus were reported 250 and higher and 500 and higher, respectively. Also, the MBC was reported 500 and 600 mg/ml, respectively. Klebsiella pneumoniae was resistant to rhubarb plant extract, and the MIC and the MBC for Staphylococcus aureus were reported 200 mg/ml and higher and 400 mg/ml and higher, respectively.
 Conclusion: The results of this study demonstrated that the hydro alcoholic extract of cinnamon, pennyroyal and rhubarb has anti bacterial effect against Klebsiella pneumoniae and Staphylococcus aureus.

Rhubarb extract incorporated into an alginate-based edible coating for peach preservation

Peaches (Prunus persica) are known for their palatable favor and abundant nutrients. However, peaches tend to rapidly decay during the harvest period in summer. To preserve the postharvest quality and extend the shelf life, an edible coating composed by 1.0% sodium alginate (SA) with and without rhubarb (Rheum rhaponticum L.) extract was applied to peach fruits. Variations in weight loss, firmness, soluble solids content (SSC), respiration rate, maleic dialdehyde (MDA) content, polyphenol oxidase (PPO) activity and sensory attributes were evaluated at room temperature (28 ± 1 °C). The effectiveness of rhubarb-SA coating to control postharvest decay of peach fruits was also investigated. The results showed that the weight loss, respiration rate, MDA content, and PPO activity were much lower, whereas the firmness and the SSC were much higher in the rhubarb-SA coated samples than in the 1.0% SA coated samples and control group. At the end of storage, peach fruits treated with rhubarb-SA coating maintained good sensory quality. Furthermore, the rhubarb-SA coating treatment had quite a beneficial effect on the decay inhibition caused by Penicillium expansum. Our study proves that the alginate coating entrapped with rhubarb extract has the potential to improve postharvest quality and prolong the shelf life of peach fruits.

ИНДУКЦИЯ ИММУНИТЕТА РАССАДЫ ТЫКВЕННЫХ КУЛЬТУР К МУЧНИСТОЙ РОСЕ В РЕЗУЛЬТАТЕ ОБРАБОТКИ ЭКСТРАКТАМИ РЕВЕНЯ

ИНДУКЦИЯ ИММУНИТЕТА РАССАДЫ ТЫКВЕННЫХ КУЛЬТУР К МУЧНИСТОЙ РОСЕ В РЕЗУЛЬТАТЕ ОБРАБОТКИ ЭКСТРАКТАМИ РЕВЕНЯ

Study of the effect of the essential oil (extract) of rhubarb stem (shoot) on glycosylated hemoglobin and fasting blood glucose levels in patients with type II diabetes.

Background: Diabetes is a serious chronic disease that can damage the heart, arteries, eyes, kidneys and nerves, leading to death and early disability. Before the discovery of insulin as well as common anti-diabetes drugs, patients with diabetes were treated with medicinal herbs and traditional treatments. One of these effective medicinal herbs is Rhubarb. Rhubarb is prescribed in traditional medicine for various patients, including patients with diabetes. But its effect has not been scientifically reported so far.Purpose: This study was conducted with the aim to determine the effectiveness of Rhubarb stem extract on HbA1C and fasting blood glucose in patients with type II diabetes.Method: In this experimental study, 80 patients with type II diabetes mellitus in Zabol diabetes center, aged 30-60 years old with fasting blood glucose greater than 140 mg/d/ were selected. Patients were randomly assigned into two groups (n = 40) of treatment with capsules of Rhubarb stem and placebo after matching the oral medications. The patients in both groups were studied for fasting blood glucose and HbA1C before and after 1 month of conducting the study.Results: The mean FBS and HbA1C in rhubarb group before the intervention were 288.80 ± 94.49 and 9.62 ± 1.58, respectively, and after the intervention were 226.42 ± 88.89 and 7.83 ± 1.50, respectively. According to the statistical paired f-test and Wilcoxon test a significant reduction was found in FBS and HbA1C with rhubarb intervention (p < 0.05).Conclusion: In diabetes mellitus, as many factors affect the level of blood glucose, they also contribute to reducing blood glucose level and preventing complications. Therefore, considering the positive effects of rhubarb, it can be recommended to use rhubarb extract as an additional treatment to reduce blood glucose level.

PTP1B inhibitory activity and molecular docking analysis of stilbene derivatives from the rhizomes of Rheum undulatum L.

Stilbene derivatives, the principal constituent of Rheum undulatum L., are known to have a wide range of biological activities, such as anti-allergic, anti-diabetic, antioxidant, and anti-inflammatory activities. A phytochemical study on the methanol extract of Korean rhubarb (R. undulatum L.) led to the isolation of nine stilbene derivatives (1–9) and one flavonoid (10). All structures were elucidated based on a comprehensive analysis of spectroscopic data. Compound 1 (5-methoxy-cis-rhapontigenin) was elucidated as a new compound, while compound 2 (5-methoxy-trans-rhapontigenin) was isolated from a natural source for the first time. Among the isolated compounds, stilbene derivatives (7–9) showed a strong inhibitory effect on protein tyrosine phosphatase 1B (PTP1B) with IC50 values ranging from 4.25 to 6.78 μM, which was significantly higher than that of the positive control, ursolic acid (IC50 = 11.34 μM). Furthermore, for the first time, kinetic analysis and molecular docking simulations were performed in order to understand the inhibition type as well as the interaction and binding mode of the active stilbenes (7–9) with PTP1B. Our results showed that the types of PTP1B inhibition were noncompetitive for ɛ-viniferin (8) and mixed for piceatannol (7) and δ-viniferin (9). Docking simulations of these stilbenes demonstrated negative binding energies and close proximity to residues in the binding pocket of PTP1B.

Inhibitory effects of methanol extracts of selected plants on proliferation of two human melanoma cell lines

Purpose: The aim of the current study was to investigate the in vitro antiproliferative activity of methanolic extracts of six plants regardless of their claimed ethnopharmacological application.Methods: Methanol extracts of different parts of Glycyrrhizaglabra L. (Licorice), Matricaria chamomilla L. (Chamomile), Salvia triloba L. (Sage), Rheum palmatum L. (Rhubarb), Trigonella foenum-graecum L. (Fenugreek) and Sambucusebulus L. (Dwarf Elder) were prepared. The antiproliferative effects of the extracts were tested on two skin cancer melanoma cell lines namely A375.S2 (low tyrosinase expression) and WM 136.1A (high tyrosinase expression) using MTT assay. The IC50 values for the active extracts were determined against the two melanoma cell lines.Results: The methanolic extracts of G.glabra, M. chamomilla, S. triloba, R. palmatum inhibited the melanotic WM1361A proliferation in a dose-dependent manner revealing IC50 values of 35.2, 25.2, 20.6, 17.8, μg/ml, respectively but not A375.S2 cell line. However, the extracts of T. foenum-graecum and S. ebulus did not exhibit any significant cytotoxic activity on both melanoma cell lines.Conclusion: The results of these experiments show that methanol extracts of licorice, chamomile, sage and rhubarb have significant antiproliferative activity onWM1361A cell line; a representative human melanotic melanocyte tumor cell line. This renders these plants as potential sources of new lead compounds for the development of new drugs for melanoma cancer.Keywords: Melanoma, Plant extract, tyrosinase, Licorice, Chamomile, Sage, Rhubarb, WM1361A

Rhubarb Protect Against Tubulointerstitial Fibrosis by Inhibiting TGF-β/Smad Pathway and Improving Abnormal Metabolome in Chronic Kidney Disease.

Tubulointerstitial fibrosis is the final common pathway for all kidney diseases leading to chronic kidney disease (CKD). TGF-β/Smad signaling pathway plays a key role in renal fibrosis. Previous studies have revealed that rhubarb extracts attenuated the increase of transforming growth factor-β 1 (TGF-β1) in CKD rats. To gain an in-depth insight into the mechanism of the anti-fibrotic activities of the rhubarb extracts, we investigated the influence of rhubarb extracts on TGF-β/Smad signaling pathway and the influence on metabolome in a rat model of CKD with adenine-induced chronic tubulointerstitial nephropathy. Male Sprague-Dawley rats were divided into four groups, including control, CKD, CKD + petroleum ether extract, CKD + ethyl acetate extract, and CKD + n-butanol extract groups. Kidneys harvested on the week three were evaluated for renal fibrosis, the expression of proteins in TGF-β/Smad signaling pathway and metabolomic study. We found rhubarb extracts suppressed TGF-β/Smad3-mediated renal fibrosis by reducing the TGF-β1, transforming growth factor-β receptor I (TGF-β RI), transforming growth factor-β receptor II (TGF-β RII), Smad2, p-Smad2, Smad3, p-Smad3, and Smad4, meanwhile increased Smad7. In addition, rhubarb extracts mitigated renal injury and dysfunction, and either fully or partially reversed the abnormalities of tissue metabolites. Thus, rebalancing the disorder of TGF-β/Smad signaling and metabolic dysfunction by treatment with rhubarb extracts may represent as an effective therapy for CKD associated with fibrosis.

Inhibitory effects of methanol extracts of selected plants on the proliferation of two human melanoma cell lines

Purpose: The aim of the current study was to investigate the in vitro antiproliferative activity of methanolic extracts of six plants regardless of their claimed ethnopharmacological application. Methods: Methanol extracts of different parts of Glycyrrhizaglabra L. (Licorice), Matricaria chamomilla L. (Chamomile), Salvia triloba L. (Sage), Rheum palmatum L. (Rhubarb), Trigonella foenum-graecum L. (Fenugreek) and Sambucusebulus L. (Dwarf Elder) were prepared. The antiproliferative effects of the extracts were tested on two skin cancer melanoma cell lines namely A375.S2 (low tyrosinase expression) and WM 136.1A (high tyrosinase expression) using MTT assay. The IC 50 values for the active extracts were determined against the two melanoma cell lines. Results: The methanolic extracts of G.glabra , M. chamomilla , S. triloba , R. palmatum inhibited the melanotic WM1361A proliferation in a dose-dependent manner revealing IC 50 values of 35.2, 25.2, 20.6, 17.8, μg/ml, respectively but not A375.S2 cell line. However, the extracts of T. foenum-graecum and S. ebulus did not exhibit any significant cytotoxic activity on both melanoma cell lines. Conclusion: The results of these experiments show that methanol extracts of licorice, chamomile, sage and rhubarb have significant antiproliferative activity onWM1361A cell line; a representative human melanotic melanocyte tumor cell line. This renders these plants as potential sources of new lead compounds for the development of new drugs for melanoma cancer. Keywords: Melanoma, Plant extract, tyrosinase, Licorice, Chamomile, Sage, Rhubarb, WM1361A

Mechanism of nephrotoxicity of rhubarb in rats

The aim of this study was to investigate the renal toxicity of rhubarb and its mechanism. The SD rats were randomly divided into three groups: normal group and two rhubarb extract groups (16, 2 g·kg⁻¹). According to the dose conversion method between human and animal, rhubarb 16 g·kg⁻¹ and 2 g·kg⁻¹ were equivalent to 10 times and 1.25 times of human clinical dose respectively. Rhubarb extract was administered by a gastric gavage to rats once daily for 30 days. Serum urea nitrogen （BUN）, creatinine （CRE） and urine KIM-1, NGAL and renal morphology were analyzed. The expressions of OAT1, OAT3 and clusterin mRNA in kidney were measured. The results showed that the low dose of rhubarb had no obvious renal toxicity. The high dose group showed mild and moderate renal injury and a down-regulation of clusterin mRNA expression in the kidney tissue. The renal toxicity in male animals was heavier than that in female animals. There was no significant change in blood BUN and CRE in the high dose group. But urine NGAL level of the high dose group increased by 51.53% compared with normal group, of which male animals increased more significantly (P<0.05, compared with the normal group). The expressions of renal OAT1 and OAT3 mRNA in the low dose group were obviously higher than that in the normal group. The results indicated that the high dose of rhubarb could cause the renal toxicity. The dosage should be controlled reasonably in the clinical use. OAT1 and OAT3 mRNA related to anionic transport in kidney tissue played a compensatory protective role in rhubarb-induced renal injury. But the compensatory effect is relatively weak at the high dose level. In addition, routine renal function indicators BUN and CRE had limitation for monitoring the kidney toxicity of rhubarb. It is suggested that urine NGAL detection might be helpful for monitoring the renal toxicity of rhubarb.

Effects of Purified Plant Extracts and Homologous Commercial Derivatives on Entamoeba histolytica growth

Entamoeba histolytica is a parasitic protist which causes amoebiasis in humans. Amoebiasis causes about 100,000 deaths every year worldwide. Currently, the antibiotic, metronidazole is the only effective treatment for amoebiasis. Metronidazole is effective; however, it has a high toxicity and causes damage to the nervous system. Finding an alternative treatment is necessary to manage the disease better and reduce the risks associated with the current medication. In previous studies, purified plant extracts and homologous commercial derivatives have shown significant antimicrobial character. Previously, we identified pomegranate, rhubarb (rhein), and maple syrup (maplifa) extracts as potential inhibitors of E. histolytica trophozoite growth. The effectiveness of the extracts was assessed by growth inhibition assays monitored at 12, 24, and 48 hours using 60 μM or 120 μM concentrations of pure compounds. Rhein and maplifa, showed promising inhibitory activity on E. histolytica trophozoite growth. Testing of compounds of analogous structures is currently in progress. Future studies will be completed to determine the biochemical mechanism of action of each of these inhibitors and test their toxicity to mammalian tissue cultures in comparison to the current drug of choice, metronidazole.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Green synthesis of silver nanoparticles and biopolymer nanocomposites: a comparative study on physico-chemical, antimicrobial and anticancer activity

The current report was intended towards comparative study of green-synthesized biogenic Rhubarb silver nanoparticles (RS-AgNPs) and chitosan crosslinked silver nanocomposites (CSHD-AgNCs). The physico-chemical characterization was done by UV–visible, FTIR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDX, TGA, XRD and zeta potential ( $$\zeta $$ ). The analysis and spectroscopic characterization was done by SEM and TEM and their results reveal that the nanoparticles are spherical in shape, with average size ranges from 5 to 50 nm, and was gathered by face centered cubic (FCC) structure throughout the polymer matrix and stable without any protecting or capping reagents over 450 days. The antimicrobial property of RS-AgNPs and CSHD-AgNCs ( $$\zeta = +29.6$$ and $$+$$ 32.8 mV) was evaluated against E. coli and S. aureus and showed an effective inhibitory property. The RS-AgNPs and CSHD-AgNCs were assessed for their anticancer activity against HeLa cell line by MTT method, and it reveals a dose–response activity, time and cell line-dependent cytotoxicity. Based on the results obtained, the RS-AgNPs exhibited higher toxicity over CSHD-AgNCs after 24 h incubation of HeLa cells with different concentrations and is negligible for the aqueous Rhubarb extract. It was concluded that the changes in anticancer activity towards HeLa cells due to biological activity of silver nanoparticles depend on their method of biosynthesis and their physico-chemical nature.

The Influence of Compatibility of Rhubarb and Radix Scutellariae on the Pharmacokinetics of Anthraquinones and Flavonoids in Rat Plasma.

Rhubarb-Radix scutellariae is a classic herb pair, which is commonly used to clear away heat and toxin in clinic. The aim of this study was to investigate the influence of compatibility of Rhubarb and Radix scutellariae on the pharmacokinetic behaviors of anthraquinones and flavonoids in rat plasma. Eighteen rats were randomly divided into three groups, and were orally administered Rhubarb and/or Radix scutellariae extracts. A sensitive and rapid UPLC-MS/MS method was developed and validated to determine the concentrations of baicalin, baicalein, wogonside, wogonin, rhein, and emodin in rat plasma. The concentrations of phase II conjugates of flavonoid aglycones and anthraquinone aglycones were also determined after hydrolyzing the plasma with sulfatase. Compared with administration of Radix scutellariae alone, co-administration of Rhubarb significantly decreased the first maximum plasma concentration (C max1) of baicalin, wogonside, and the phase II conjugates of baicalein, wogonin to 46.40, 61.27, 41.49, and 20.50%, respectively. The area under the plasma concentration-time curve from time zero to infinity (AUC0-∞) was significantly decreased from 82.60±20.22 to 51.91±7.46μM·h for rhein and 276.83±98.02 to 175.42±86.82μM·h for the phase II conjugates of wogonin after compatibility. The time to reach the first maximum plasma concentration (T max1) of anthraquinones was shortened and the second peak of anthraquinones disappeared after compatibility. Compatibility of Rhubarb and Radix scutellariae can significantly affect the pharmacokinetic behaviors of characteristic constituents of the two herbs. The cause of these pharmacokinetic differences was further discussed combined with the in vivo ADME (absorption, disposition, metabolism, and excretion) processes of anthraquinones and flavonoids.

Influence of Rhubarb extract on the expression of NGAL and IL-18 in the kidney of rabbits after CPR

To study the preventive effect and mechanism of Rhubarb extract on renal injury after cardiopulmonary resuscitation (CPR) in rabbits with cardiac arrest (CA). Twenty-four male Japanese big-ear rabbits were divided into sham operation group, CPR model group and Rhubarb pretreatment group by random number table method, with 8 rabbits in each group. The rabbits in Rhubarb pretreatment group were treated with Rhubarb extract 5 mL×kg-1×d-1 for 7 days; and those in sham operation group and CPR model group were fed with 0.9% normal saline 10 mL/d for 7 days. After 7 days, ventricular fibrillation (VF) was produced in CPR model group and Rhubarb pretreatment group by 50 V alternating currents stimulation through bottom of the heart leads to the apex to prepare CPR model. The rabbits of the CPR model group and Rhubarb pretreatment group were sacrificed at 2 hours after successful resuscitation, and the animals in the sham operated group were sacrificed directly after anesthesia. The levers of blood urea nitrogen (BUN) and creatinine (Cr) in serum were examined by automatic biochemical analyzer. The positive expression area of neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) in kidney were examined by immunohistochemistry. Compared with the sham operation group, the levels of BUN and Cr were significantly increased in the CPR model group and Rhubarb pretreatment group [BUN (mmol/L): 15.53±3.90, 10.51±3.16 vs. 7.03±2.23, Cr (μmol/L): 137.20±12.23, 86.80±7.67 vs. 66.39±5.47, both P < 0.05]. Compared with the CPR model group, the levels of BUN and Cr were significantly decreased in the Rhubarb pretreatment group [BUN (mmol/L): 10.51±3.16 vs. 15.53±3.90, Cr (μmol/L): 86.80±7.67 vs. 137.20±12.23, both P < 0.05]. Immunohistochemical staining showed that the expression of NGAL and IL-18 mainly existed in glomerular and tubular cells in patina. Compared with the sham operation group, the positive expression areas of NGAL and IL-18 in kidney were significantly increased in the CPR model group and Rhubarb pretreatment group [NGAL (μm2): 208.26±7.58, 136.74±5.33 vs. 98.93±7.83, IL-18 (μm2): 256.48±4.64, 113.22±6.98 vs. 77.06±6.47, all P < 0.05]. Compared with the CPR model group, the positive expression areas of NGAL and IL-18 were significantly decreased in the Rhubarb pretreatment group [NGAL (μm2): 136.74±5.33 vs. 208.26±7.58, IL-18 (μm2): 113.22±6.98 vs. 256.48±4.64, both P < 0.05]. CA can lead to acute kidney injury (AKI). Rhubarb extract can reduce the expression of NGAL and IL-18 in kidney of rabbits after CPR, and protect the kidney after CPR.