Rheum rhaponticum and Rheum rhabarbarum Extracts as Modulators of Endothelial Cell Inflammatory Response.

BACKGROUND: Inflammation, endothelial dysfunction, and alterations in blood physiology are key factors contributing to atherosclerosis and other cardiovascular disorders. Hence, modulation of endothelial function and reducing its pro-inflammatory and pro-thrombotic activity is considered one of the most important cardioprotective strategies. This study aimed to evaluate the anti-inflammatory potential of rhubarb extracts isolated from petioles and underground organs of Rheum rhabarbarum L. (garden rhubarb) and R. rhaponticum L. (rhapontic rhubarb) as well as two stilbenoids, typically found in these plants, i.e., rhapontigenin (RHPG) and its glycoside, rhaponticin (RHPT). METHODS: Analysis of the anti-inflammatory effects of the indicated rhubarb-derived substances involved different aspects of the endothelial cells' (HUVECs) response: release of the inflammatory mediators; cyclooxygenase (COX-2) and 5-lipoxygenase (5-LOX) expression as well as the recruitment of leukocytes to the activated HUVECs. The ability of the rhubarb-derived extracts to inhibit COX-2 and 5-LOX activities was examined as well. The study was supplemented with the in silico analysis of major components of the analyzed extracts' interactions with COX-2 and 5-LOX. RESULTS: The obtained results indicated that the examined plant extracts and stilbenes possess anti-inflammatory properties and influence the inflammatory response of endothelial cells. Biochemical and in silico tests revealed significant inhibition of COX-2, with special importance of rhaponticin, as a compound abundant in both plant species. In addition to the reduction in COX-2 gene expression and enzyme activity, a decrease in the cytokine level and leukocyte influx was observed. Biochemical tests and computational analyses indicate that some components of rhubarb extracts may act as COX-2 inhibitors, with marginal inhibitory effect on 5-LOX.

Corrigendum: Inhibitory effects of Rhaponticin on osteoclast formation and resorption by targeting RANKL-induced NFATc1 and ROS activity.

[This corrects the article DOI: 10.3389/fphar.2021.645140.].

Simultaneous determination of 10 rhubarb anthraquinones and rhaponticin in Compound gentian and sodium bicarbonate tablets by UPLC / 中国药房

OBJECTIVE To establish a method for the simultaneous determination of 10 rhubarb anthraquinones in Compound gentian sodium bicarbonate tablets and the content of rhaponticin，which are the characteristic components of artifacts，and to use the method to evaluate the quality of compound preparation containing Rheum officinale. METHODS The ultra-performance liquid chromatography （UPLC） method was adopted to determine the contents of 10 rhubarb anthraquinones （aloe-emodin-8-O-glucoside， rheinic acid-8-O-β-D-glucoside，emodin-8-O-glucoside，chrysophanol-8-O-β-D-glucoside，emodin monomethyl ether-8-O-β-D-glucoside， aloe-emodin，rheinic acid，emodin，chrysophanol，emodin monomethyl ether） and rhaponticin in 40 batches of Compound gentian sodium bicarbonate tablets from 8 manufacturers. The determination was performed on the Agilent Eclipse Plus C18 column with a mobile phase consisted of acetonitrile-0.1% phosphoric acid solution （gradient elution） at a flow rate of 0.3 mL/min； the column temperature was set at 30 ℃ ，and the injection volume was 5 μL. Combining principal component analysis and cluster analysis to synthesize the results of content determination，the quality of samples from different manufacturers was evaluated. RESULTS All of above 11 components showed favorable linear relationships with peak areas in their respective mass concentration ranges （r≥0.999 3），with RSDs of precision，repeatability and stability 296261547@qq.com less than 3% （n＝6）； average sample recoveries ranged 96.82%-98.92% （RSD≤1.74%，n＝6）； their contents were 0971-8247794。E-mail：304436784@qq.com 0.011 7-0.252 0，0-0.323 3，0.131 3-1.236 6，0.081 1-1.056 2，0.015 2-0.189 8，0.001 8-0.152 3，0-0.255 2，0.001 9-0.223 4，0.054 3-0.303 0，0.022 7-0.172 2，0-2.835 9 mg/g，respectively. The cumulative variance contribution of the first three principal components was 95.533%； the 40 batches of samples can be clustered into 4 categories：samples from enterprises a and d were in a category of their own，samples from enterprises f，b，g and e were in a category，and samples from enterprises c and h were in a category. There were large differences in the content of rhubarb anthraquinone in the samples from 8 manufacturers，and rhaponticin was only detected in the sample from one enterprise. CONCLUSIONS Established UPLC method is stable and reliable； it can be used for the content determination of 10 rhubarb anthraquinones and rhaponticin in Compound gentian sodium bicarbonate tablets.

Computational Simulations Highlight the IL2Rα Binding Potential of Polyphenol Stilbenes from Fenugreek.

Widely used in global households, fenugreek is well known for its culinary and medicinal uses. The various reported medicinal properties of fenugreek are by virtue of the different natural phytochemicals present in it. Regarded as a promising target, interleukin 2 receptor subunit alpha (IL2Rα) has been shown to influence immune responses. In the present research, using in silico techniques, we have demonstrated the potential IL2Rα binding properties of three polyphenol stilbenes (desoxyrhaponticin, rhaponticin, rhapontigenin) from fenugreek. As the first step, molecular docking was performed to assess the binding potential of the fenugreek phytochemicals with IL2Rα. All three phytochemicals demonstrated interactions with active site residues. To confirm the reliability of our molecular docking results, 100 ns molecular dynamics simulations studies were undertaken. As discerned by the RMSD and RMSF analyses, IL2Rα in complex with the desoxyrhaponticin, rhaponticin, and rhapontigenin indicated stability. The RMSD analysis of the phytochemicals alone also demonstrated no significant structural changes. Based on the stable molecular interactions and comparatively slightly better MM/PBSA binding free energy, rhaponticin seems promising. Additionally, ADMET analysis performed for the stilbenes indicated that all of them obey the ADMET rules. Our computational study thus supports further in vitro IL2Rα binding studies on these stilbenes, especially rhaponticin.

Inhibitory Effects of Rhaponticin on Osteoclast Formation and Resorption by Targeting RANKL-Induced NFATc1 and ROS Activity.

The extravagant osteoclast formation and resorption is the main cause of osteoporosis. Inhibiting the hyperactive osteoclastic resorption is considered as an efficient treatment for osteoporosis. Rhaponticin (RH) is a small molecule that has been reported to possess anti-inflammatory, anti-allergic, anti-fibrotic, and anti-diabetic activities. However, the influence of RH on osteoclasts differentiation and function is still unclear. To this end, an array of assays including receptor activator of nuclear factor kappa-Β (NF-κB) ligand (RANKL) induced osteoclastogenesis, tartrate-resistant acidic phosphatase (TRAcP) staining, immunofluorescence, and hydroxyapatite resorption were performed in this study. It was found that RH had significant anti-catabolic effects by inhibiting osteoclastogenesis and bone resorption without cytotoxicity. Mechanistically, the expression of NADPH oxidase 1 (Nox1) was found to be suppressed and antioxidant enzymes including catalase, superoxide dismutase 2 (SOD-2), and heme oxygenase-1(HO-1) were enhanced following RH treatment, suggesting RH exhibited antioxidant activity by reducing the generation of reactive oxygen species (ROS) as well as enhancing the depletion of ROS. In addition, MAPKs, NF-κB, and intracellular Ca2+ oscillation pathways were significantly inhibited by RH. These changes led to the deactivation of osteoclast master transcriptional factor-nuclear factor of activated T cells 1 (NFATc1), as examined by qPCR and Western blot assay, which led to the decreased expression of downstream integrin ß3, c-Fos, cathepsin K, and Atp6v0d2. These results suggested that RH could effectively suppress RANKL-regulated osteoclast formation and bone resorption. Therefore, we propose that RH can represent a novel natural small molecule for the treatment of osteoporosis by inhibiting excessive osteoclast activity.

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.

Rhaponticin suppresses osteosarcoma through the inhibition of PI3K-Akt-mTOR pathway.

Osteosarcoma is the frequent pediatric bone cancer where pediatric osteosarcoma incidences are more than 10% within the population. Most of the patients with osteosarcoma fall within the age of 15-30 years. Therefore, in this research, we examined the anticancer effect of Rhaponticin against the human osteosarcoma (MG-63) cells. The cytotoxicity of Rhaponticin on the MC3T3-E1 and MG-63 cells was examined through the MTT assay. The intracellular ROS accumulation, cell nuclear morphological alterations, apoptotic cell death and nuclear damages, and MMP status of Rhaponticin administered MG-63 cells were inspected by fluorescent staining techniques. The cell migration was assessed through scratch assay. The mRNA expressions of PI3K-Akt-mTOR signaling proteins were studied by RT-PCR analysis. Rhaponticin showed potent cytotoxicity, substantially inhibited the MG-63 cell growth, and displayed morphological alterations. However, rhaponticin did not affect the MC3T3-E1 cell viability. Rhaponticin administered MG-63 cells demonstrated augmented intracellular ROS accretion, weakened MMP, increased nuclear damages, and increased apoptosis. Rhaponticin effectively down-regulated the PI3K-Akt-mTOR signaling cascade in the MG-63 cells. These outcomes proved that the Rhaponticin can be a hopeful chemotherapeutic agent in the future to treat human osteosarcoma.

Protective effect of rhaponticin on ovariectomy-induced osteoporosis in rats.

Rhaponticin is a constituent isolated from numerous medicinal herbs. It has been reported earlier that rhaponticin possesses numerous biological effects like antiallergic, antidiabetic, hepatoprotective, and antithrombosis. The goal of this exploration was to scrutinize the therapeutic potential of rhaponticin on ovariectomy (OVX)-triggered osteoporosis in rats. Female Sprague Dawley rats were arbitrarily allocated to a sham-operated control group I, group II, which underwent OVX, and groups III and IV that underwent OVX were administered with rhaponticin (10 and 20 mg/kg). Rhaponticin was supplemented orally after 4 weeks of OVX and continued for about 16 weeks. Our findings exhibit that rhaponticin prevented the BMD diminution of femurs, induced by OVX, and protected the worsening of trabecular microarchitecture that are assisted through a noteworthy decline in skeletal remodeling as noticed through the diminished status of bone markers in a dose-dependent manner (10 and 20 mg/kg). OVX rats treated with rhaponticin efficiently enhanced body weight, lipid profiles, uterine index, bone turnover markers, inflammatory markers, and augmented the incidence of calcium in the OVX rats. Rhaponticin was established to restrain the functions of acid phosphatase, estradiol, and bone gla protein in OVX rats. Also, rhaponticin displayed some beneficial effects on histomorphometric and histopathological examination. It was observed that tabular area and thickness were reinstated in sham control and rhaponticin-treated OVX rats. We recognized that rhaponticin did not induce a damaging outcome on the skeletal organization of OVX rats. Moreover, we denote that rhaponticin can be an exceptional agent for the treatment and deal with associated bone diseases.

Rhaponticin contained Rheum officinale root extract improved Postmenopause symptom of Ovariectomized Rat.

Postmenopausal women have decreased levels of the hormone estrogen. Reduced estrogen levels will often involve many symptoms that reduced quality of life. This research aims to analyze the effects of Rheum officinale root extract on postmenopausal model rats. To this end, thirty rats underwent ovariectomy (OVX) surgery and six rats were operated without having their ovaries removed. The OVX was confirmed by body weight-uterus weight ratio and a vaginal swab. Six groups of the rats were performed: SHAM group and negative control groups are given vehicle; the positive control was assigned tamoxifen; and the extract has been given three doses 7, 35, and 175 mg/200 g BW, respectively, for 30 days. The calcium content of bone ash was measured using atomic absorption spectrophotometer. Blood pressure was evaluated using CODA®, and the metabolites in the blood were assessed using gas chromatography-mass spectrometry (MS) and high-performance liquid chromatography. As a result, using ultra-performance liquid chromatography (UPLC)-MS, we found that the extract's major component was rhaponticin and its metabolites. The bone calcium levels increased with increasing doses of the extract. In the OVX group, the bone calcium content was decreased significantly 51.56% ± 8.9% g compared with the SHAM group 62.97% ±5.6% g, and the administration of Rheum extract could restore the calcium content of the bone to become 69.27% ± 3.8% g. From the above data, we concluded that Rheum root extracts contain astrigin, rhaponticin, rhapontigenin, and desoxyrhaponticin. Rheum root extract could improve calcium content and lipid profiles of OVX rats by stimulation osteoblastogenesis. Rheum root extracts could control the blood pressure of OVX rats by reducing lipid profiles.

Anti-inflammatory effects of rhaponticin on LPS-induced human endothelial cells through inhibition of MAPK/NF-κß signaling pathways.

The untreated systemic chronic inflammation leads to autoimmune diseases, hyperglycemia, cardiovascular diseases, type 2 diabetes, hypertension, osteoporosis, and so on. Phytochemicals effectively inhibit the inflammation, and numerous studies have proved that the phytocomponents possess anti-inflammatory property via inhibiting the cyclooxygenase and lipoxygenase signaling pathways. Rhaponticin is one such phytochemical obtained from the perennial plant Rheum rhaponticum L. belonging to Polygonaceae family. We assessed the anti-inflammatory potency of rhaponticin in endothelial cells induced with lipopolysaccharides (LPS). Four different endothelial cells induced with LPS were treated with rhaponticin and assessed for the nitric oxide generation. The cytotoxic potency of rhaponticin was evaluated in endothelial cells using the 3-(4,5-dimethylthizaol-2yl)-2,5-diphenyl tetrazolium bromide assay. The tumor necrosis factor-α (TNF-α) synthesis was quantified using the commercially available assay kit. The inflammatory signaling protein gene expression of TNF-α, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and interleukin-1ß (IL-1ß) was analyzed with quantitative polymerase chain reaction (PCR) analysis. The gene expression of NADPH oxidase (NOX) cytoplasmic catalytic subunits gp91phox , p47phox , and p22phox was assessed with real-time PCR analysis. Finally, to confirm the anti-inflammatory potency of rhaponticin, the nuclear factor kappa B (NFκB) and mitogen-activated protein kinase (MAPK) signaling protein expression was analyzed with immunoblotting analysis. Rhaponticin treatment significantly decreased the levels of nitric oxide and TNF-α synthesis in LPS-induced endothelial cells. It significantly decreased the gene expression of inflammatory proteins and NOX signaling protein. The protein expression of NFκB and MAPK signaling proteins was drastically decreased in rhaponticin-treated endothelial cells induced with LPS. Overall, our results confirm that rhaponticin effectively inhibited the inflammation triggered by LPS in endothelial cells via downregulating iNOS, COX2, and NFκB and MAPK signaling pathways.

Neuroprotective effect of rhaponticin against Parkinson disease: Insights from in vitro BV-2 model and in vivo MPTP-induced mice model.

Parkinson's disease (PD) is a complex neurodegenerative illness associated with the loss or damage to neurons of the dopaminergic system in the brain. Few therapeutic approaches and considerable side effects of conventional drugs necessitate a new therapeutic agent to treat patients with PD. Rhaponticin is a natural hydroxystilbene, found in herbal plants such as Rheum rhaponticum, and known to have desirable biological activity including anti-inflammatory properties. However, the neuroinflammation on rhaponticin levels has only been investigated partially so far. So, the current study explored whether rhaponticin could ameliorate the pathophysiology observed in both the in vitro microglial BV-2 cells and the in vivo (1-methyl-4-phenyl-1,2,3,5-tetrahydropyridine [MPTP])-mediated PD model. The results show rhaponticin significantly attenuated lipopolysaccharide (LPS)-mediated microglial activation by suppressing nitric oxide synthase in conjunction with abridged reactive oxygen species production together with proinflammatory mediator reduction. In vivo rhaponticin treatment improves motor impairments as well as the loss of dopaminergic neurons in MPTP-treated mice possibly through suppression via mediators of inflammation. Taken together, these results offer evidence that rhaponticin exerts anti-inflammatory effects and neuroprotection in an LPS-induced microglial model and the MPTP-induced mouse models of PD.

Effects of rhaponticin on retinal oxidative stress and inflammation in diabetes through NRF2/HO-1/NF-κB signalling.

Oxidative stress and inflammation have long been considered to be responsible for the development and progression of diabetic retinopathy. On the other hand, rhaponticin (RN) has received scientific attention due to its various pharmacological properties. Keeping all these in view, the present study was performed to investigate the potential protective effects of RN on the retina in diabetic rats. Rats were randomly divided into three groups: control group rats, diabetic group rats, diabetic + RN (20 mg/kg body weight for 28 days through oral route) group rats. RN supplementation to diabetic rats significantly prevent the reduction of final body weight loss, reduced weekly fasting blood glucose levels and HbA1c levels with a significant increase in serum insulin levels. quantitative polymerase chain reaction and immunohistochemical analysis found upregulation of Nrf2, NQO-1, HO-1 and upregulation of Keap1 genes and protein distribution along with significantly reduced levels of malondialdehyde and increased activity of superoxide dismutase, catalase and glutathione peroxidase in RN-treated diabetic rats as compared to diabetic rats. Furthermore, treatment of diabetic rats with RN showed downregulated expression of tumour necrosis factor-α, matrix metalloproteinase-2 and upregulated expression of interleukin-10 (IL-10) and TIMP-1 in the retina. RN treatment decreased nuclear factor kappa-light-chain-enhancer of activated B cells distribution and increased IL-10 protein distribution in the retinae of diabetic rats. In addition, RN treatment ameliorated morphological changes observed in retinae of diabetic rats. Altogether, these results provided clear evidence that treatment of diabetic rats with RN attenuated diabetic retinal changes through its hypoglycaemic, antioxidant and anti-inflammatory effects.

Metabolism of Rhaponticin and Activities of its Metabolite, Rhapontigenin: A Review.

Rhaponticin is a stilbenoid glucoside compound, found in medicinal plant of rhubarb rhizomes. Rhapontigenin (RHAG), the stilbene aglycone metabolite of rhaponticin, has shown various biological activities including anticancer activities to act a potential human cytochrome P450 inhibitor, antihyperlipidemic effect, anti-allergic action, antioxidant and antibacterial activities. Moreover, it was reported to scavenge intracellular Reactive Oxygen Species (ROS), the 1,1-Diphenyl-2-Picrylliydrazyl (DPPH) radical, and Hydrogen Peroxide (H2O2). Meanwhile, RHAG exhibited the inhibitory activity for the synthesis of DNA, RNA and protein, and also presented the capacity of inducing morphological changes and apoptosis of C. albicans. Here, the structure, pharmacokinetics, pharmacological effects as well as underlying mechanisms of rhaponticin and its metabolite, RHAG, have been extensively reviewed. This review will provide a certain reference value for developing the therapeutic drug of rhaponticin or RHAG.

Optimum Detection Method for the Key Indicators of Authenticity for Rhaponticin Identification in Rhei Radix et Rhizoma Based on 2015 Edition of Chinese Pharmacopoeia / 中国中医药信息杂志

Objective To establish a simple and specific method for the determination of rhaponticin in Rhei Radix et Rhizoma. Methods A comparison of the methods of polyamide, silica gel TLC and HPLC in the determination of rhaponticin was studied to investigate the optimum way to identify authentic Rhei Radix et Rhizoma. Results The durability of polyamide and silica gel TLC method for the determination of rhaponticin in Rhei Radix et Rhizoma was poor. HPLC method was more suitable for the detection of rhaponticin. Conclusion HPLC method is accurate and reliable, and can be used for the quality control of Rhei Radix et Rhizoma and provide references for the authenticity of Rhei Radix et Rhizoma.

Interaction between a novel folate receptor targeted rhaponticin conjugate and human serum albumin by molecular spectroscopy / 国际药学研究杂志

Objective To investigate the affinity and inteaction of a folate receptor targeted rhapontion (RHA) conjugate (FRHA) with human serum albumins(HSA). Method The interaction between FRHA and HSA under physiological conditions was investigated by fluorescence spectroscopy, UV- visual (vis) spectroscopy and circular dichroism (CD) spectroscopy. Great attempts were made to investigate their interaction mechanism regarding the quenching mechanism, the specific binding site, the type of interaction force, and the effect of FRHA on the micro-environmental and conformational changes in HSA molecules. Results The formation of the complex of FRHA-HSA would lead to fluorescence quenching. The corresponding values of Ka were 1.4322×105, 1.1793× 105, 0.9334×105 and 0.7896×105 L/mol when the temperature were 298, 302, 306, and 310 K, respectively. The enthalpy change (ΔH) and entropy change (ΔS) were calculated to be -38.772 kJ/mol and -31.39 J/(mol·K), indicating that van der Waals force and hydrogen bonds played major roles in stabilizing the complex. Conclusion The interaction process of the formation of FRHA-HSA is spontaneous. The negative values of enthalpy change (ΔH) and entropy change (ΔS) indicate that van der Waals force and hydrogen bonds play major roles in stabilizing the complex. The conformational investigation reveals the α·-helical structure is decreased and the microenvironment of HSA is changed upon the addition of FRHA. The fluorescence quenching of HSA caused by FRHA is static quenching. Furthermore, the results of site marker competitive experiment suggest that FRHA binds to the sub-domain II A of HSA.

Interaction between a novel folate receptor targeted rhaponticin conjugate and human serum albumin by molecular spectroscopy / 国际药学研究杂志

Objective To investigate the affinity and interaction of a folate receptor targeted rhapontion(RHA)conjugate (FRHA)with human serum albumins(HSA). Method The interaction between FRHA and HSA under physiological conditions was investigated by fluorescence spectroscopy,UV-visual(vis)spectroscopy and circular dichroism(CD)spectroscopy. Great attempts were made to investigate their interaction mechanism regarding the quenching mechanism,the specific binding site,the type of inter-action force,and the effect of FRHA on the micro-environmental and conformational changes in HSA molecules. Results The forma-tion of the complex of FRHA-HSA would lead to fluorescence quenching. The corresponding values of Ka were 1.4322 × 105,1.1793 × 105,0.9334 × 105 and 0.7896 × 105 L/mol when the temperature were 298,302,306,and 310 K,respectively. The enthalpy change (ΔH)and entropy change(ΔS)were calculated to be-38.772 kJ/mol and-31.39 J/(mol·K),indicating that van der Waals force and hydrogen bonds played major roles in stabilizing the complex. Conclusion The interaction process of the formation of FRHA-HSA is spontaneous. The negative values of enthalpy change(ΔH)and entropy change(ΔS)indicate that van der Waals force and hydrogen bonds play major roles in stabilizing the complex. The conformational investigation reveals theα-helical structure is decreased and the microenvironment of HSA is changed upon the addition of FRHA. The fluorescence quenching of HSA caused by FRHA is static quenching. Furthermore,the results of site marker competitive experiment suggest that FRHA binds to the sub-domainⅡA of HSA.

The interaction between BLF and BSA and impact in interaction of RT-BSA-BLF system / 药学学报

The binding of rhaponticin to bovine serum albumin (BSA)-bovine lactoferrin (BLF) and the factors that affect BSA-BLF interaction have been studied by fluorescence spectroscopy and Fourier transform infrared spectroscopy. In the fluorescence experiment, RT quenched the fluorescence intensity of mixed proteome and the maximum emission wavelength of BSA, BLF and BSA-BLF proteins system. RT caused obvious red-shift fluorescence for an interaction between RT and proteome. The interaction between RT and proteome was impacted by single-component protein molecular interactions and the interaction between RT-BSA and RT-BLF, the microenvironment of solutions were the factors impacting the interactions between RT and proteome, which impacted quantitative expression of the general environment micro environmental factors. In the Fourier transform infrared spectroscopy, the secondary conformation of protein molecules of single component in the protein group were changed, and the difference of the molecules' structure was responsible for the differences in the molecular conformation changes. The molecules' interaction in the single-component protein affected secondary conformation of the proteins' molecule. The proteins' concentration ratio and the interaction were different in degree of molecular conformational change. These data demonstrates an example of combination of fluorescence spectrum experiment with Fourier transform infrared spectroscopy in the study of protein structura.

Larix laricina bark, a traditional medicine used by the Cree of Eeyou Istchee: Antioxidant constituents and in vitro permeability across Caco-2 cell monolayers.

ETHNOPHARMACOLOGICAL RELEVANCE: Larix laricina, a native tree of North America, is a highly respected medicinal plant used for generations by Indigenous Peoples across its range, including the Cree of northern Québec who use the bark to treat symptoms of diabetes. This study investigates the antioxidant capacity and bioavailability of active constituents identified in L. laricina bark extracts. MATERIALS AND METHODS: (1) Oxygen radical absorbance capacity (ORAC) assay was employed to test antioxidant capacity of organic extracts (80% ethanol) from bark of L. laricina as well as fractions, isolated compounds, and media samples collected during permeability assays. (2) Caco-2 cell monolayer cultures were used to determine the permeability of identified antioxidants, which were quantified in basolateral media samples using liquid chromatography - tandem mass spectrometry (HPLC-ESI-MS/MS). RESULTS: Crude ethanolic extract possessed strong antioxidant potential in vitro (7.1±0.3 Trolox equivalents (TE) µM/mg). Among the 16 L. laricina fractions obtained by chromatographic separation, fraction 10 (F10) showed the highest antioxidant capacity (21.8±1.7µm TE/mg). Among other identified antioxidants, the stilbene rhaponticin (isolated from F10) was the most potent (24.6±1.1µm TE/mg). Caco-2 transport studies revealed that none of the identified compounds were detectable in basolateral samples after 2-h treatment with crude extract. In monolayers treated with F10 (60% rhaponticin), small quantities of rhaponticin were increasingly detected over time in basolateral samples with an apparent permeability coefficient (Papp) of 1.86×10-8cm/s (0-60min). To model potential effects on blood redox status, we evaluated the antioxidant capacity of collected basolateral samples and observed enhanced activity over time after exposure to both extract and F10 (75µg/mL) relative to control. CONCLUSIONS: By profiling the antioxidant constituents of L. laricina bark, we identified rhaponticin as the most potent oxygen radical scavenger and observed low permeability in Caco-2 cell monolayers but an increase in basolateral antioxidant capacity.

Anti-oxidative activities of ethanol extracts from both wild plant and suspension cell cultures of rheum franzenbachii / 中草药·英文版

Objective: To evaluate the content of rhaponticin and anti-oxidative activities of the ethanol extracts from both the wild plants and suspension cell cultures of Rheum franzenbachii. Methods: Quantitative analysis of rhaponticin was performed by HPLC. The anti-oxidative activities of the ethanol extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assays. Results: The content of rhaponticin in the roots of the wild plant was 4.36 mg/g, while the content was only 1.59 mg/g in the leaves. The content of rhaponticin in suspension cells cultured on Murashige and Skoog (MS) medium supplemented with 1.0 mg/L 6-benzylaminopurine (6-BAP) and 2.0 mg/L 2,4-dicholorophenoxy acetic acid (2,4-D) was 17.64 mg/g, which increased by 4.05 times compared with the content in the roots of the wild plants. The roots of wild plants displayed the strongest anti-oxidative activity, followed by the suspension cells 5 and 6, and the scavenging percent was 91.96%, 91.23%, and 89.27%, respectively, at the concentration of 100 μg/mL. The IC50 values were 2.477, 15.644, and 31.415 μg/mL, respectively. In particular, the DPPH scavenging activity of the ethanol extracts from the roots of the wild plant was generally comparable to the control of ascorbic acid (VC), and the IC50 value of the extracts was lower than that of VC (2.502 μg/mL). Conclusion: Rhaponticin production in the cell culture can be modulated and the accumulation can be increased. The roots of the wild plant display the strongest anti-oxidative activity. These results suggest that R. franzenbachii could hold a good potential source for human health. © 2014 Tianjin Press of Chinese Herbal Medicines.

A simple and rapid spectrofluorimetric method for determining the pharmacokinetics and metabolism of rhaponticin in rat plasma, feces and urine using a cerium probe.

Rhaponticin (RH) demonstrates a variety of pharmacological activities, including antitumor, antithrombotic and antioxidant effects. It is essential to establish a simple, rapid and reliable analytical method for determining the pharmacokinetics of RH. A simple cerium ion (Ce(3+)) probe method was developed and validated to determine RH in rat plasma, feces and urine. The fluorescence intensities of the cerium ion (Ce(3+)) were quenched by addition of RH, along with a remarkable red shift. Spectral data revealed that fluorescence quenching of Ce(3+) by RH was due to the formation of a Ce(3+)-RH complex. Using to the Stern-Volmer equation, the binding parameters for interactions between Ce(3+) and RH were obtained. Based on these, a rapid and simple spectrofluorimetric method was developed to determine the metabolism and pharmacokinetics of RH using a Ce(3+) probe. The assay was linear over the concentration range of 0.11-9.52, 0.25-8.87 and 0.18-9.10 µM for plasma, feces and urine, respectively and RH recoveries were found to be 98.24 ± 0.8, 97.78 ± 1.2 and 97.54 ± 0.8% for plasma, feces and urine, respectively. The relative standard deviations were < 9.5%. The spectrofluorimetric method was simple and rapid for quantitative determination of RH and its metabolism, and was affordable for most laboratories because of the fluorescence spectroscopy and low equipment cost. These pharmacokinetic, bioavailability and metabolism studies of RH will provide helpful information for the development of suitable dosage forms and clinical references on rational administration.