Chemical constituents of Rubia tibetica Hook. f. from Tibetan medicine and cytotoxic activity evaluation.

Two unprecedented quinone compounds Rubiaxylm A (1) and Rubiaxylm B (2), along with fifteen known anthraquinones (3-17) were isolated and characterized from the roots of Rubia tibetica in Tibetan medicine. Their structures were identified through comprehensive analyses of 1D/2D NMR as well as HR-ESIMS data. Furthermore, all separated compounds were evaluated for their cytotoxic activity on A549, Caco-2, MDA-MB-231 and Skov-3 cell lines. In particular, compound 2 effectively inhibited MDA-MB-231 cells with an IC50 value of 8.15 ± 0.20 µM. Subsequently, the anti-tumor mechanism of 2 was investigated by flow cytometry, JC-1 staining, cell scratching and cell colony. These results indicated that compound 2 could inhibit the proliferation of MDA-MB-231 cells by arresting cells in the G1 phase.

Chemical constituents from the aerial parts of Rubia cordifolia L. with their NO inhibitory activity.

A new naphthoquinone derivative (1) together with twenty-three known compounds (2-24), were isolated from the aerial parts of Rubia cordifolia L. Their structures were elucidated on the basis of NMR and HR-ESIMS data. Compounds 1-13 were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells. Compounds 2-6 exhibited significant inhibitory activities with IC50 values of 21.37, 13.81, 24.56, 20.32, and 30.08 µmol·L-1, respectively.

TLC-MS-Bioautographic Identification of Antityrosinase Compounds and Preparation of a Topical Gel Formulation from a Bioactive Fraction of an RSM-Optimized Alcoholic Extract of Rubia Cordifolia L. stem.

BACKGROUND: Rubia cordifolia L., Rubiaceae, is globally reported to treat skin-related problems. The study aimed to assess the antityrosinase potential of Rubia cordifolia (ARC) and the development of gel formulation. METHODS: The AutoDock Vina (version V.1.2.0) program package was used for molecular docking to check for the binding affinity of ligands with protein. Response surface methodology (RSM) software was used to optimize extraction parameters for an alcoholic extract of Rubia cordifolia (ARC). The developed HPTLC method for the quantification of purpurin in ARC was validated as per the International Conference on Harmonization (ICH) guidelines. A bioautographic study for the evaluation of antityrosinase effects was performed; an anthraquinone-enriched fraction (AEF)-loaded gel formulation developed and evaluated physicochemically which could be used to reduce skin pigmentation. RESULTS: Purpurin showed optimum binding affinity (-7.4 kcal/mol) with the molecular target (tyrosinase) when compared to that of standard kojic acid (-5.3 kcal/mol). Quantification of purpurin in ARC, optimized by RSM software, was validated and physiologically significant results were observed for the antityrosinase potential of an AEF, along with TLC-MS-bioautographic identification for antityrosinase compounds: purpurin (m/z 256.21) and ellagic acid (m/z 302.19). Evaluation of an AEF-loaded gel formulation by in vitro and ex vivo permeation studies was performed. CONCLUSION: ARC extraction parameters optimized by RSM, and a bioautographic study helped identify antityrosinase compounds. The development of a gel formulation could be a cost-effective option for the treatment of depigmentation in the future. HIGHLIGHTS: A TLC-MS-Bioautography-based Identification of Antityrosinase Compounds and development of AEF-loaded Topical Gel formulation from a Bioactive Fraction of an RSM-Optimized Alcoholic Extract of Rubia Cordifolia L. stem, which could help with promising results in reducing skin pigmentation and maintaining even tone.

The Underling Mechanisms Exploration of Rubia cordifolia L. Extract Against Rheumatoid Arthritis by Integrating Network Pharmacology and Metabolomics.

Purpose: Rubia cordifolia L. (RC) is a classic herbal medicine for the treatment of rheumatoid arthritis (RA) and has been used since ancient times. The ethanol extract of Rubia cordifolia L. (RCE) showed obvious anti-RA effects in our previous study. However, further potential mechanisms require more exploration. We aimed to investigate the mechanism of RCE for the treatment of RA by integrating metabolomics and network pharmacology in this study. Methods: An adjuvant-induced arthritis (AIA) rat model was established, and we evaluated the therapeutic effects of RCE. Metabolomics of serum and urine was used to identify the differential metabolites. Network pharmacology was applied to determine the key metabolites and potential targets. Finally, the potential targets and compounds of RCE were verified by molecular docking. Results: The results indicated that RCE suppressed foot swelling and alleviated joint damage and also had anti-inflammatory properties by inhibiting the expressions of tumor necrosis factor (TNF)-α, Interleukin (IL)-1ß, prostaglandin E2 (PGE2), and P65. Ten and seven differential metabolites were found in the serum and urine, respectively, of rats. Six key targets, ie, phospholipase A2 group IIA (PLA2G2A), phospholipase A2 group X (PLA2G10), cytidine deaminase (CDA), uridine-cytidine kinase 2 (UCK2), charcot-leyden crystal galectin (CLC), and 5',3'-nucleotidase, mitochondrial (NT5M), were discovered by network pharmacology and metabolite analysis and were found to be related to glycerophospholipid metabolism and pyrimidine metabolism. Molecular docking confirmed that the favorable compounds showed affinities with the key targets, including alizarin, 6-hydroxyrubiadin, ruberythric acid, and munjistin. Conclusion: This study revealed the underlying mechanisms of RCE and provided evidence that will allow researchers to further investigate the functions and components of RCE against RA.

ZnO Nanoparticles of Rubia cordifolia Extract Formulation Developed and Optimized with QbD Application, Considering Ex Vivo Skin Permeation, Antimicrobial and Antioxidant Properties.

The objective of the current research is to develop ZnO-Manjistha extract (ZnO-MJE) nanoparticles (NPs) and to investigate their transdermal delivery as well as antimicrobial and antioxidant activity. The optimized formulation was further evaluated based on different parameters. The ZnO-MJE-NPs were prepared by mixing 10 mM ZnSO4·7H2O and 0.8% w/v NaOH in distilled water. To the above, a solution of 10 mL MJE (10 mg) in 50 mL of zinc sulfate was added. Box-Behnken design (Design-Expert software 12.0.1.0) was used for the optimization of ZnO-MJE-NP formulations. The ZnO-MJE-NPs were evaluated for their physicochemical characterization, in vitro release activity, ex vivo permeation across rat skin, antimicrobial activity using sterilized agar media, and antioxidant activity by the DPPH free radical method. The optimized ZnO-MJE-NP formulation (F13) showed a particle size of 257.1 ± 0.76 nm, PDI value of 0.289 ± 0.003, and entrapment efficiency of 79 ± 0.33%. Drug release kinetic models showed that the formulation followed the Korsmeyer-Peppas model with a drug release of 34.50 ± 2.56 at pH 7.4 in 24 h. In ex vivo studies ZnO-MJE-NPs-opt permeation was 63.26%. The antibacterial activity was found to be enhanced in ZnO-MJE-NPs-opt and antioxidant activity was found to be highest (93.14 ± 4.05%) at 100 µg/mL concentrations. The ZnO-MJE-NPs-opt formulation showed prolonged release of the MJE and intensified permeation. Moreover, the formulation was found to show significantly (p < 0.05) better antimicrobial and antioxidant activity as compared to conventional suspension formulations.

Visualization of the distribution of anthraquinone components from madder roots in rat kidneys by desorption electrospray ionization-time-of-flight mass spectrometry imaging.

Madder color (MC), a natural dye isolated from Rubia tinctorum, is a potent carcinogen that targets the outer stripe of outer medulla (OSOM) in the kidneys of rats. To clarify the role of MC components in renal carcinogenesis, we examined distributions of MC components and metabolites in the kidneys of rats treated with MC using desorption electrospray ionization-mass spectrometry imaging (DESI-MSI). Alizarin, lucidin, munjistin, nordamnacanthal, purpurin, pseudopurpurin, rubiadin, and some other metabolites detected and identified by liquid chromatography time-of-flight MS analysis of rat serum 1 h after MC administration were subjected to DESI-MSI. This analysis enabled visualization of the distribution of anthraquinones in the kidney, and the ion images showed a characteristic distribution according to their chemical structure. Among the components, lucidin and rubiadin specifically localized in the OSOM, suggesting that their genotoxicity was a direct cause of MC carcinogenesis. Alizarin showed greater distribution in the OSOM than the cortex and may therefore participate in renal carcinogenicity owing to its tumor-promoting activity. Overall, our data suggested that the distribution of carcinogenic components to the OSOM was responsible for the site-specific renal carcinogenicity of MC and that DESI-MSI analysis may be a powerful tool for exploring the mechanisms of chemical carcinogenesis.

Chemistry, Biosynthesis, Physicochemical and Biological Properties of Rubiadin: A Promising Natural Anthraquinone for New Drug Discovery and Development.

Anthraquinones (AQs) are found in a variety of consumer products, including foods, nutritional supplements, drugs, and traditional medicines, and have a wide range of pharmacological actions. Rubiadin, a 1,3-dihydroxy-2-methyl anthraquinone, primarily originates from Rubia cordifolia Linn (Rubiaceae). It was first discovered in 1981 and has been reported for many biological activities. However, no review has been reported so far to create awareness about this molecule and its role in future drug discovery. Therefore, the present review aimed to provide comprehensive evidence of Rubiadin's phytochemistry, biosynthesis, physicochemical properties, biological properties and therapeutic potential. Relevant literature was gathered from numerous scientific databases including PubMed, ScienceDirect, Scopus and Google Scholar between 1981 and up-to-date. The distribution of Rubiadin in numerous medicinal plants, as well as its method of isolation, synthesis, characterisation, physiochemical properties and possible biosynthesis pathways, was extensively covered in this review. Following a rigorous screening and tabulating, a thorough description of Rubiadin's biological properties was gathered, which were based on scientific evidences. Rubiadin fits all five of Lipinski's rule for drug-likeness properties. Then, the in depth physiochemical characteristics of Rubiadin were investigated. The simple technique for Rubiadin's isolation from R. cordifolia and the procedure of synthesis was described. Rubiadin is also biosynthesized via the polyketide and chorismate/o-succinylbenzoic acid pathways. Rubiadin is a powerful molecule with anticancer, antiosteoporotic, hepatoprotective, neuroprotective, anti-inflammatory, antidiabetic, antioxidant, antibacterial, antimalarial, antifungal, and antiviral properties. The mechanism of action for the majority of the pharmacological actions reported, however, is unknown. In addition to this review, an in silico molecular docking study was performed against proteins with PDB IDs: 3AOX, 6OLX, 6OSP, and 6SDC to support the anticancer properties of Rubiadin. The toxicity profile, pharmacokinetics and possible structural modifications were also described. Rubiadin was also proven to have the highest binding affinity to the targeted proteins in an in silico study; thus, we believe it may be a potential anticancer molecule. In order to present Rubiadin as a novel candidate for future therapeutic development, advanced studies on preclinical, clinical trials, bioavailability, permeability and administration of safe doses are necessary.

Rubioncolin C, a natural naphthohydroquinone dimer isolated from Rubia yunnanensis, inhibits the proliferation and metastasis by inducing ROS-mediated apoptotic and autophagic cell death in triple-negative breast cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Rubia yunnanensis Diels is a traditional Chinese medicine that has diverse pharmacological activities, including antituberculosis, antirheumatism and anticancers. Rubioncolin C (RC), a natural naphthohydroquinone dimer isolated from the roots and rhizomes of R. yunnanensis Diels, has shown potent antitumor activity. However, the antitumor activity and its potential mechanism of RC in triple-negative breast cancer (TNBC) cell lines remained unclear. AIM OF THE STUDY: This study was aim to investigate the anti-proliferation and anti-metastasis activity as well as the potential mechanism of RC on triple-negative breast cancer cells in vitro and in vivo. MATERIALS AND METHODS: The sulforhodamine B assay, colony formation assay and cell cycle analysis were used to determine the anti-proliferative activity of RC on TNBC. The anti-metastatic activity in vitro of RC was detected through the scratch wound assay, cell migration and invasion assays and gelatin zymography. The flow cytometry, JC-1, GFP-LC3B plasmid transfection, MDC, Lysotracker red and Carboxy-H2DCFDA, DHE, and MitoSOX™ Red staining were performed to investigate the effect of RC on apoptosis, autophagy and ROS level. The apoptosis inhibitor, autophagy inhibitors and ROS inhibitors were used to further verify the antitumor mechanism of RC. The protein levels related with cell cycle, apoptosis, and autophagy were examined with western blotting. In addition, the anti-tumor activity of RC in vivo was assessed in an experimental metastatic model. RESULTS: In the present study, RC suppressed the proliferation of TNBC cells in a time- and dose-dependent manner via regulating cell cycle. Further experiments showed that RC inhibited the migration and invasion of TNBC cells by downregulating MMPs and inhibiting EMT. Moreover, we demonstrated that RC induced obviously apoptotic and autophagic cell death, activated MAPK signaling pathway and inhibited mTOR/Akt/p70S6K and NF-κB signaling pathways. Furthermore, the excessive ROS was produced after treatment with RC. The antioxygen NAC and GSH could rescue the cell viability and reestablish the ability of cell metastasis, and inhibit the RC-induced apoptosis and autophagy. In a mice lung metastasis model of breast cancer, RC inhibited lung metastasis, and induced autophagy and apoptosis. CONCLUSION: These findings clarified the antitumor mechanism of RC on TNBC cell lines and suggested that RC is a key active ingredient for the cancer treatment of R. yunnanensis, which would help RC develop as a new potential chemotherapeutic agent for TNBC treatment.

Antioxidant and Polyphenol-Rich Ethanolic Extract of Rubia tinctorum L. Prevents Urolithiasis in an Ethylene Glycol Experimental Model in Rats.

Treatment of kidney stones is based on symptomatic medications which are associated with side effects such as gastrointestinal symptoms (e.g., nausea, vomiting) and hepatotoxicity. The search for effective plant extracts without the above side effects has demonstrated the involvement of antioxidants in the treatment of kidney stones. A local survey in Morocco has previously revealed the frequent use of Rubia tinctorum L. (RT) for the treatment of kidney stones. In this study, we first explored whether RT ethanolic (E-RT) and ethyl acetate (EA-RT) extracts of Rubia tinctorum L. could prevent the occurrence of urolithiasis in an experimental 0.75% ethylene glycol (EG) and 2% ammonium chloride (AC)-induced rat model. Secondly, we determined the potential antioxidant potency as well as the polyphenol composition of these extracts. An EG/AC regimen for 10 days induced the formation of bipyramid-shaped calcium oxalate crystals in the urine. Concomitantly, serum and urinary creatinine, urea, uric acid, phosphorus, calcium, sodium, potassium, and chloride were altered. The co-administration of both RT extracts prevented alterations in all these parameters. In the EG/AC-induced rat model, the antioxidants- and polyphenols-rich E-RT and EA-RT extracts significantly reduced the presence of calcium oxalate in the urine, and prevented serum and urinary biochemical alterations together with kidney tissue damage associated with urolithiasis. Moreover, we demonstrated that the beneficial preventive effects of E-RT co-administration were more pronounced than those obtained with EA-RT. The superiority of E-RT was associated with its more potent antioxidant effect, due to its high content in polyphenols.

H2O-Induced Hydrophobic Interactions in MS-Guided Counter-Current Chromatography Separation of Anti-Cancer Mollugin from Rubia cordifolia.

Counter-current chromatography (CCC) is a unique liquid-liquid partition chromatography and largely relies on the partition interactions of solutes and solvents in two-phase solvents. Usually, the two-phase solvents used in CCC include a lipophilic organic phase and a hydrophilic aqueous phase. Although a large number of partition interactions have been found and used in the CCC separations, there are few studies that address the role of water on solvents and solutes in the two-phase partition. In this study, we presented a new insight that H2O (water) might be an efficient and sensible hydrophobic agent in the n-hexane-methanol-based two-phase partition and CCC separation of lipophilic compounds, i.e., anti-cancer component mollugin from Rubia cordifolia. Although the n-hexane-methanol-based four components solvent systems of n-hexane-ethyl acetate-methanol-water (HEMWat) is one of the most popular CCC solvent systems and widely used for natural products isolation, this is an interesting trial to investigate the water roles in the two-phase solutions. In addition, as an example, the bioactive component mollugin was targeted, separated, and purified by MS-guided CCC with hexane-methanol and minor water as a hydrophobic agent. It might be useful for isolation and purification of lipophilic mollugin and other bioactive compounds complex natural products and traditional Chinese medicines.

RA-XII, a bicyclic hexapeptidic glucoside isolated from Rubia yunnanensis Diels, exerts antitumor activity by inhibiting protective autophagy and activating Akt-mTOR pathway in colorectal cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Rubia yunnanensis Diels (Chinese name 'Xiao-Hong-Shen'), a traditional Chinese medicine native to Yunnan province (China), have a long history of use for treating several diseases, such as tuberculosis, rheumatism and cancers. A bicyclic hexapeptidic glucoside named RA-XII was isolated from R. yunnanensis, which has been reported to exert anti-inflammatory and antitumor activities. AIM OF THE STUDY: This study was designed to investigate the antitumor activity and potential mechanism of RA-XII on colorectal cancer (CRC) cell lines. MATERIALS AND METHODS: Sulforhodamine B assay, clonogenic assay and cell cycle analysis were conducted to assess the anti-proliferative activity of RA-XII on CRC cells. GFP-LC3B plasmid transfection, MDC and AO staining assays, cathepsin activity assay, and siRNAs against several genes were used to investigate the effect of RA-XII on autophagy. Western blotting was used to examine the expression levels of proteins associated with cell cycle arrest, apoptosis and autophagy. Human CRC xenograft-bearing BALB/c nude mice were used to evaluate the antitumor effect of RA-XII in vivo. RESULTS: RA-XII showed favorable antineoplastic activity in SW620 and HT29 cells in vitro and in vivo. RA-XII did not induce apoptosis indicated by no obvious changes on mitochondrial membrane potential and apoptosis-related marker proteins in SW620 or HT29 cells. Treatment of RA-XII inhibited the formation of autophagosomes, which is implied by the GFP-LC3 fluorescent dots, MDC-stained autophagic vesicles and LC3 protein expression. It was indicated that RA-XII suppressed autophagy by regulating several signaling pathways including mTOR and NF-κB pathways. Pharmacological or genetic inhibition of autophagy could enhance the cytotoxicity of RA-XII while autophagy inducer could rescue RA-XII-induced cell death. Besides, RA-XII could increase the susceptibility of CRC cells to bortezomib. CONCLUSION: Our study demonstrated that RA-XII exerted antitumor activity independent of apoptosis, and suppressed protective autophagy by regulating mTOR and NF-κB pathways in SW620 and HT29 cell lines, which suggested that RA-XII is a key active ingredient for the cancer treatment of Rubia yunnanensis and possesses a promising prospect as an autophagy inhibitor for CRC therapy.

Anti-inflammatory Activity of Mollugin on DSS-induced Colitis in Mice.

We aimed to explore the anti-inflammatory activity of mollugin extracted from Rubia cordifolia L, a traditional Chinese medicine, on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. Thirty C57BL/6 mice were divided into a control group (n=6), a model group (n=6), and three experimental groups (40, 20, 10 mg/kg of mollugin, n=6 each). DSS solution (3%) was given to mice in the model group and experimental groups from day 4 to day 10 to induce the mouse UC model. Mice in the experimental groups were intragastrically administrated mollugin from day 1 to day 10. Animals were orally given distilled water in the control group for the whole experiment time and in the model group from day 1 to day 3. The changes in colon pathology were detected by hematoxylin and eosin (HE) staining. Interleukin-1ß (IL-1ß) in the serum, and tumor necrosis factor-α (TNF-α) and interferon-γ (IFN) in the tissues were measured by enzyme linked immunosorbent assay. Expression levels of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 in the colon tissues were detected by immunohistochemistry. Results showed that mollugin could significantly reduce weight loss and the disease activity index in the DSS-induced UC mouse model. HE examinations demonstrated that mollugin treatment effectively improved the histological damage (P<0.05). The overproduction of IL-1ß and TNF-α was remarkably inhibited by mollugin treatment at doses of 20 and 40 mg/kg (P<0.05). Additionally, the levels of TLR4 in colon tissues were significantly reduced in mollugin-treated groups compared with the DSS group. Our findings demonstrated that mollugin ameliorates DSS-induced UC by inhibiting the production of pro-inflammatory chemocytokines.

TMARg, a Novel Anthraquinone Isolated from Rubia cordifolia Nakai, Increases Osteogenesis and Mineralization through BMP2 and ß-Catenin Signaling.

BACKGROUND: Plant extracts have long been regarded as useful medicines in the treatment of human diseases. Rubia cordifolia Nakai has been used as a traditional medicine, as it has pharmacological properties such as antioxidant and anti-inflammatory activity. However, the biological functions of TMARg, isolated from the roots of R. cordifolia, in osteoblast differentiation remain unknown. This study was performed to investigate the pharmacological effects and intracellular signaling of TMARg in the osteoblast differentiation of pre-osteoblast MC3T3-E1 cells and mesenchymal precursor C2C12 cells. METHODS: Cell viability was evaluated using an MTT assay. Early and late osteoblast differentiation was examined by analyzing the activity of alkaline phosphatase (ALP), and by staining it with Alizarin red S (ARS). Cell migration was determined by using migration assays. Western blot analysis and immunocytochemical analysis were used to examine the intracellular signaling pathways and differentiation proteins. RESULTS: In the present study, TMARg showed no cytotoxicity and increased the osteoblast differentiation in pre-osteoblasts, as assessed from the alkaline phosphate (ALP) staining and activity and ARS staining. TMARg also induced BMP2 expression and increased the p-smad1/5/8-RUNX2 and ß-catenin pathways in both MC3T3-E1 and C2C12 cells. Furthermore, TMARg activated mitogen-activated protein kinases (MAPKs) and increased the cell migration rate. In addition, the TMARg-mediated osteoblast differentiation was suppressed by BMP and Wnt inhibitors with the downregulation of BMP2 expression. CONCLUSION: These findings demonstrate that TMARg exerts pharmacological and biological effects on osteoblast differentiation through the activation of BMP2 and ß-catenin signaling pathways, and suggest that TMARg might be a potential phytomedicine for the treatment of bone diseases.

Development of an ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry method for determination of xanthopurpurin in rat plasma and its application to pharmacokinetic study.

A rapid and sensitive method was developed and validated for the quantitative determination of xanthopurpurin (XPP) in rat plasma using ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry. XPP inhibits IgE production and prevents peanut-induced anaphylaxis. The XPP and emodin (internal standard) were determined in negative ion mode with m/z 239.0350 → 211.0400 and 269.0455 → 241.0507, respectively. The separation process was achieved using an ACQUITY UPLC HSS T3 column with acetonitrile and 0.1% formic acid in water (85:15). The linear range was 0.5-100 ng/mL, and the correlation coefficient (r2 ) was > 0.993. The inter-day and intra-day precision was within an acceptable range of 15%. The extraction recovery and matrix effect were 78.9-87.2% and 94.3-98.5%, respectively. Under different conditions, the XPP was stable in the range of 5.6-10.6%. This method was successfully applied to study the pharmacokinetics of XPP with an oral dose of 10.0 mg/kg and intravenous dose of 2.0 mg/kg in rats. The absolute oral bioavailability of XPP was 4.6%.

Green synthesis of silver nanoparticles using Rubia tinctorum extract and evaluation the anti-cancer properties in vitro.

Cancer is one of the leading causes of human death. Nanotechnology could offer new and optimised anticancer agents in order to fight cancer. It was shown that metal nanoparticles, in particular silver nanoparticles (AgNPs) were effective in cancer therapy. In this study, AgNPs were synthesised using Rubia tinctorum L. extract (Ru-AgNPs). Then, cytotoxicity effects of the Ru-AgNPs against MDA-MB-231 carcinoma cell line and human dermal fibroblast as normal cell line were performed. Furthermore, anti-apoptotic effects of Ru-AgNPs on these cancer and normal cell lines were compared using acridine orange/propidium iodide staining, flow cytometry analysis and real-time qPCR in apoptosis gene markers. Results of UV-vis spectroscopy showed that Ru-AgNPs have a peak at 430 nm, which indicated synthesis of AgNPs. Ru-AgNPs had spherical shape and average size of 12 nm. Ru-AgNPs have cytotoxicity on MDA-MB-231 cells and decrease cancerous cell viability (IC50 = 4 µg/ml/48 h). Ru-AgNPs could induce apoptosis in MDA-MB-231 cells through upregulation of Bax and downregulation of Bcl-2 gene expression. The results opened up new avenues to develop Rubia based metal complexes as an anticancer agent.

Network pharmacology-based research on the active component and mechanism of the antihepatoma effect of Rubia cordifolia L.

Rubia cordifolia L. is widely used in Asia and its antihepatoma effect has been proved by in vitro and in vivo experiments. However, there are few studies on its specific mechanism. In the present study, the network pharmacology method was used to construct the component/target/pathway molecular regulatory network for the antihepatoma effect of Rubia cordifolia L. to explore the effective components of Rubia cordifolia L. and its potential mechanism. The chemical components of Rubia cordifolia L. were identified through literature and databases, and the components were evaluated and screened by drug likeness and pharmacokinetic characteristics (ADMET). The targets of active components were predicted according to the reverse pharmacophore matching model. The hepatic carcinoma-related genes were found in databases, and antihepatoma-related gene targets were selected through comparison. The functions of target genes and related pathways were analyzed and screened using the Database for Annotation, Visualization and Integrated Discovery, and the component/target/pathways network of antihepatoma effect of Rubia cordifolia L. was constructed using Cytoscape software. Finally, 16 active compounds were screened from Rubia cordifolia L., and 39 gene targets, including AKT1, mitogen-activated protein kinase 1, and epidermal growth factor receptor, were involved. Rubia cordifolia L. also affected the hepatitis B, phosphoinositide-3-kinase-protein kinase B, and mitogen-activated protein kinase signaling pathways. Many direct-acting tumor-related signaling pathways and indirect-acting hepatitis pathways inhibit the generation of liver cancer. The present study provided a scientific basis for further elucidating the mechanism of Rubia cordifolia L. against liver cancer.

Cytotoxic properties of the anthraquinone derivatives isolated from the roots of Rubia philippinensis.

BACKGROUND: Cancer is one of the most frequently occurring diseases and is the second leading cause of death worldwide. In this study, anthraquinone derivatives (Compounds 1-5) were evaluated for their anti-cancer potential against various skin and breast cancer cell lines to assess whether these anthraquinone derivatives may serve as a lead for the augmentation of anti-cancer drug. METHODS: Anthraquinone derivatives, 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(6'-O-acetyl)-α-rhamnosyl(1 → 2)-ß-glucoside (Comp 1), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone (Comp 2), and alizarin (Comp 3) were isolated from the dichloromethane fraction of the roots of Rubia philippinensis., whereas ethyl acetate fraction yielded xanthopurpurin (Comp 4) and lucidin-ω-methyl ether (Comp 5). Structures of all the isolated compounds were determined by spectral data analysis. All isolated compounds (Comp 1-5) were assessed for cytotoxicity by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against four different cancer cell lines, i.e. human melanoma (SK-MEL-5), murine melanoma (B16F10), and human breast adenocarcinoma (MCF7 and MDA-MB-231). RESULTS: Significant activity of the compounds 4 and 5 was observed against the breast cancer cell line MDA-MB-231 with IC50 values of 14.65 ± 1.45 and 13.03 ± 0.33 µM, respectively. Encouragingly, IC50 values of 67.89 ± 1.02 and 79.01 ± 0.03 µM against normal kidney epithelial cells (MDCK) were also obtained for compounds 4 and 5, respectively, which indicated very low toxicity and favorable selectivity indices for compounds 4 and 5 in the range of 1.85 to 3.95 and 2.11 to 6.06 against skin cancer cell lines (SK-MEL-5, and B16F10), and breast cancer cell lines (MCF7 and MDA-MB-231), respectively. CONCLUSION: Our results suggested that the compounds 4 (xanthopurpurin) and 5 (lucidin-ω-methyl ether) showed high selective toxicity towards breast cancer cells at lower concentrations without showing toxicity towards normal cells, thus could be of potential as new lead molecules in cancer treatment.

Evaluation of analgesic and anti-inflammatory activities of Rubia cordifolia L. by spectrum-effect relationships.

The objective of the current work was to evaluate the spectrum-effect relationships between high-performance liquid chromatography fingerprints and analgesic and anti-inflammatory effects of Rubia cordifolia L. extract (RCE), and to identify active components of RCE. Chemical fingerprints of ten batches of RC from various sources were obtained by HPLC, and similarity and hierarchical clustering analyses were carried out. Pharmacodynamic assays were performed in adjuvant-induced arthritis rat model to assess the analgesic and anti-inflammatory properties of RCE. The spectrum-effect relationships between chemical fingerprints and the analgesic and anti-inflammatory effects of RCE were established by gray correlation analysis. UPLC-ESI-MS was used to identify the structures of potential active components, by reference standards comparison. The results showed that a close correlation existed between chemical fingerprints with analgesic and anti-inflammatory activities, and alizarin, 6-hydroxyrubiadin, purpurin and rubiadin might be the active constituents of RCE. In addition, RCE attenuated pathological changes in adjuvant-induced arthritis. The current findings provide a strong basis for combining chemical fingerprints with analgesic and anti-inflammatory activities in assessing the spectrum-effect relationships of RCE.

Rubipodanones A-D, naphthohydroquinone dimers from the roots and rhizomes of Rubia podantha.

Four previously undescribed naphthohydroquinone dimers named rubipodanones A-D, together with 19 known quinones containing three known napthohydroquinone dimers named rubioncolin C, methyl 5-hydroxy-dinaphtho[1,2-2',3']furan-7,12-dione-6-carboxylate and rubialatin B, were isolated from the roots and rhizomes of Rubia podantha. Their structures and absolute configurations were determined mainly by NMR, X-ray diffraction, and computational methods. Rubipodanones C and D, the glycosides of rubipodanone A and a pair of C-3 epimer, are the first identified dimeric napthohydroquinone glycosides from the Rubia plants. All naphthohydroquinone dimers were evaluated for their cytotoxicities against ten tumor cell lines and effects on the tumor-associated NF-κB signaling pathway, and rubioncolin C showed the best cytotoxicity with IC50 value of 1.53 µM and NF-κB inhibitory activity with IC50 value of 2.97 µM. These results also demonstrated that the key roles of C-3 configuration and sugar group for biological activities of rubipodanone C.