In Vitro Free Radical and ONOO- Scavengers from Sophora flavescens

Structure-activity relationship studies of pyrogallol as a calcineurin/NFAT signaling suppressor

Previously, we have shown that pyrogallol alleviated nasal symptoms and suppressed IL-9 gene up-regulation in allergy model rats by inhibiting calcineurin/NFAT signaling. As pyrogallol has antioxidative activity, it may be responsible for inhibiting calcineurin/NFAT signaling-mediated IL-9 gene expression. However, the relationship between antioxidative activity and suppression of IL-9 gene expression has not been elucidated yet. Here, we conducted the structure-activity relationship studies of pyrogallol and its structurally related compounds to understand the mechanism of IL-9 gene suppression by pyrogallol. 2, 2-Diphenyl-1-picrylhydrazyl radical scavenging assay showed that the antioxidative activity of catechol, resorcinol, phloroglucinol, and gallic acid is 60.1%, 10.4%, 18.8%, and 113.5% of pyrogallol, respectively. Catechol, resorcinol, and phloroglucinol did not suppress NFAT dephosphorylation. Gallic acid suppressed dephosphorylation of NFAT. Gallic acid also suppressed ionomycin-induced up-regulation of IL-9 gene expression with the IC50 value of 82.6 μM. However, catechol, resorcinol and phloroglucinol showed no suppressive activity. In addition, using gallic acid-immobilized beads, we isolated and identified Poly(U)-binding-splicing factor 60 (PUF60) as a pyrogallol binding protein. These results suggest that the antioxidative activity of pyrogallol is not likely to be the mechanism of IL-9 gene suppression. Data also suggest that PUF60 is one of its target molecules responsible for the suppression of calcineurin/NFAT signaling by pyrogallol.

Flavonoids From the Aerial Parts of Sophora tonkinensis and Their Potential Anti-Inflammatory Activities

Four undescribed prenylated flavonoids, sophoratones A-D (1-4), and 17 known flavonoids, were obtained from the aerial parts of Sophora tonkinensis. Their structures with absolute configurations were elucidated by detailed interpretation of NMR spectroscopy, mass spectrometry, and ECD calculations. Meanwhile, the ability of these compounds to inhibit the release of nitric oxide (NO) by a lipopolysaccharide induced mouse in RAW 264.7 cells was assayed. The results indicated that some compounds exhibited clear inhibitory effects, with IC50 ranging from 19.91±1.08 to 35.72±2.92 μM. These results suggest that prenylated flavonoids from the aerial parts of S. tonkinensis could potentially be used as a latent source of anti-inflammatory agents.

New benzoic acid glycosides from Sophora flavescens

Two new benzoic acid derivatives, sophophenoside A (1) and sophophenoside B (2), were isolated from Sophora flavescens. Their structures were elucidated by detailed spectroscopic analysis and chemical methods. Compounds 1 and 2 were assayed for their hepatoprotective activity on the cytotoxic effect of D-galactosamine on HL-7702 cells, and compound 1 exhibited a moderate hepatoprotective activity at a concentration of 10 μM.

The flavonoids of Sophora flavescens exerts anti-inflammatory activity via promoting autophagy of Bacillus Calmette-Guérin-stimulated macrophages

Tuberculosis (TB), a highly infectious air-borne disease, has remained a global health problem. Conventional treatment and preventions such as antibiotics and Bacilli Calmette-Guerin (BCG) vaccine can be unreliable. In view of the increasing prevalence of anti-TB drug resistance, adjunctive therapy may be necessary to shorten the recovery time. We have previously shown that flavonoids in the medicinal herb Sophora flavescens exhibit anti-inflammatory and bactericidal activities. The aim of this study was to investigate the molecular and cellular characteristics of flavonoids of S. flavescens (FSF) in BCG-stimulated macrophages for assessing their roles in anti-inflammation and autophagy. Mouse alveolar macrophage (MH-S) cell line and primary mouse peritoneal macrophages were stimulated in vitro with heat-inactivated BCG and treated with FSF, with or without autophagy inhibitor Bafilomycin A1 (BafA1). Gene expression was analyzed using quantitative PCR, and cytokine/chemokine release was analyzed by Milliplex assay and ELISA. Autophagy-related proteins were quantified by Western blot and flow cytometry, and autophagolysosomes were detected using fluorescence microscopy. In both MH-S cell line and mouse peritoneal macrophages stimulated by heat-inactivated BCG, FSF was found to up-regulate autophagy-related proteins microtubule-associated protein 1A/1B-light chain 3 (LC3) and protein 62 (p62), and suppress the induced proinflammatory cytokine TNF-α, CCL5, and IL-6. FSF actively modulates immune processes through suppressing BCG-mediated inflammation by promoting autophagy in MH-S cells and mouse peritoneal macrophages. We suggest that FSF may be useful as an adjunctive therapeutic agent for TB infection by modulating cell survival through autophagy and reducing inflammation.

Flavonoid Compounds Contained in Epimedii Herba Inhibit Tumor Progression by Suppressing STAT3 Activation in the Tumor Microenvironment

M2-like tumor-associated macrophages (TAMs) in the tumor tissues promote tumor progression by various mechanisms and represent possible targets of antitumor therapy. In the present study, we tested whether compounds from Epimedii Herba inhibit macrophage polarization to the M2/protumorigenic phenotype and prevent tumor progression, using human monocyte-derived macrophages (HMDMs) and an animal sarcoma model. Four Epimedii Herba-derived flavonoid compounds, namely, limonianin, epimedokoreanin B, icaritin, and desmethylicaritin, inhibited CD163 expression and interleukin (IL)-10 production, which are known M2 markers, suggesting that these compounds inhibit M2 polarization. Among these compounds, epimedokoreanin B and limonianin suppressed STAT3 activation in HMDMs. Notably, epimedokoreanin B also suppressed cell proliferation by blocking STAT3 activation in Saos-2 human sarcoma and LM8 mouse sarcoma cell lines. Furthermore, oral administration of epimedokoreanin B inhibited tumor growth in an LM8 tumor-bearing murine model. These results indicate that Epimedii Herba and Epimedii Herba-derived compounds, such as epimedokoreanin B, may be potentially new agents that can be used for the treatment and prevention of various malignant tumors. They may also be promising compounds for targeting the tumor microenvironment by inhibiting M2 polarization of the TAMs.

Capillary electrophoresis fingerprints combined with Linear Quantitative Profiling Method to monitor the quality consistency and predict the antioxidant activity of Alkaloids of Sophora flavescens

Alkaloids of Sophora flavescens (ASF) has various pharmacological effects, and it is widely used in clinical practice. The aim of this research was to develop an environmentally friendly methodology that enables not only identification but also the quality consistency assessment of Alkaloids of Sophora flavescens. A background electrolyte composed of 50 mmol/L sodium tetraborate solution, 500 mmol/L boric acid and 1.2 mmol/L citric acid was used to conduct the fingerprint analysis coupled with quantitative determination of three components. Linear quantitative profiling method was used for comprehensive quality discrimination of the test samples from both qualitative and quantitative perspectives, and the 27 batches of samples were well differentiated. In addition, the fingerprint-efficacy relationship between chemical components and antioxidant activity in vitro was established using partial least squares regression model, which provided important medicinal efficacy information for quality control.

Potent selective monoamine oxidase B inhibition by maackiain, a pterocarpan from the roots of Sophora flavescens

Monoamine oxidase (MAO) catalyzes the oxidation of monoamines and its two isoforms, MAO-A and MAO-B, break down neurotransmitter amines. Of the compounds isolated from the roots of Sophora flavescens, (-)-maackiain (4), a pterocarpan, was found to potently and selectively inhibit human MAO-B, with an IC50 of 0.68μM, and to have a selectivity index of 126.2 for MAO-B. As compared with other herbal natural products, the IC50 value of 4 for MAO-B is one of the lowest reported to date. Genistein (1) highly, effectively and non-selectively inhibited MAO-A and MAO-B with IC50 values of 3.9μM and 4.1μM, respectively. (-)-4-Hydroxy-3-methoxy-8,9-methylenedioxypterocarpan (2) effectively and non-selectively inhibited MAO-A and MAO-B with IC50 values of 20.3μM and 10.3μM, respectively. In addition, compound 4 reversibly and competitively inhibited MAO-B with a Ki value of 0.054μM. Molecular docking simulation revealed that the binding affinity of 4 for MAO-B (-26.6kcal/mol) was greater than its affinity for MAO-A (-8.3kcal/mol), which was in-line with our inhibitory activity findings. Furthermore, Cys172 of MAO-B was found to be a key residue for hydrogen bonding with compound 4. The findings of this study suggest compound 4 be viewed as a new potent, selective, and reversible MAO-B inhibitor, and that compounds 1 and 2 be considered useful lead compounds for the developments of nonselective and reversible MAO inhibitors for the treatment of disorders like Parkinson's disease, Alzheimer disease, and depression.

Desmethylanhydroicaritin isolated from Sophora flavescens, shows antitumor activities in U87MG cells via inhibiting the proliferation, migration and invasion

This study is the first report of the antitumor activities of desmethylanhydroicaritin (DMAI) isolated from Sophora flavescens on U87MG cells. Human glioblastoma is one of the most aggressive malignant type of brain tumors and highly diffuses to around normal brain tissues. DMAI showed anti-proliferation effects on U87MG cells at the concentration of 30μM, however did not affect to HEK-293 cells. DMAI induced anti-proliferation effects via ERK/MAPK, PI3K/Akt/mTOR signal pathway and G2/M phase cell cycle arrest. DMAI led to morphological change and inhibition of filapodia formation through regulation of Rac 1 and Cdc 42. In addition, migration and invasion of U87MG cells were inhibited by DMAI via down-regulation of matrix metalloproteinase (MMP) -2 and MMP -9 expressions and activities. Our results suggest that DMAI has a potential as a therapeutic agent against glioblastoma cells.

Maackiain is a novel antiallergic compound that suppresses transcriptional upregulation of the histamine H1 receptor and interleukin-4 genes

Kujin contains antiallergic compounds that inhibit upregulation of histamine H1 receptor (H1R) and interleukin (IL)-4 gene expression. However, the underlying mechanism remains unknown. We sought to identify a Kujin-derived antiallergic compound and investigate its mechanism of action. The H1R and IL-4 mRNA levels were determined by real-time quantitative RT-PCR. To investigate the effects of maackiain in vivo, toluene-2,4-diisocyanate (TDI)-sensitized rats were used as a nasal hypersensitivity animal model. We identified (-)-maackiain as the responsible component. Synthetic maackiain showed stereoselectivity for the suppression of IL-4 gene expression but not for H1R gene expression, suggesting distinct target proteins for transcriptional signaling. (-)-Maackiain inhibited of PKCδ translocation to the Golgi and phosphorylation of Tyr(311) on PKCδ, which led to the suppression of H1R gene transcription. However, (-)-maackiain did not show any antioxidant activity or inhibition of PKCδ enzymatic activity per se. Pretreatment with maackiain alleviated nasal symptoms and suppressed TDI-induced upregulations of H1R and IL-4 gene expressions in TDI-sensitized rats. These data suggest that (-)-maackiain is a novel antiallergic compound that alleviates nasal symptoms in TDI-sensitized allergy model rats through the inhibition of H1R and IL-4 gene expression. The molecular mechanism underlying its suppressive effect for H1R gene expression is mediated by the inhibition of PKCδ activation.

Safety evaluation of Angelica gigas: Genotoxicity and 13-weeks oral subchronic toxicity in rats

As a well-known traditional medicine, Angelica gigas (AG) and its active constituents, including decursin and decursinol, have been shown to possess several health beneficial properties such as anti-bacterial, immunostimulating, anti-tumor, neuroprotective, anti-nociceptive and anti-amnestic activities. However, there is lack of toxicity studies to assess potential toxicological concerns, especially long-term toxicity and genotoxicity, regarding the AG extract. Therefore, the safety of AG extract was assessed in subchronic toxicity and genotoxicity assays in accordance with the test guidelines published by the Organization for Economic Cooperation and Development. In a subchronic toxicity study for 13 weeks (125, 250, 500, 1000 and 2000 mg/kg body weight, delivered by gavage), data revealed no significant adverse effects of the AG extract in food consumption, body weight, mortality, hematology, biochemistry, necropsy, organ weight and histopathology throughout the study in male and female rats. These results suggest that no observed adverse effect level of the AG extract administered orally was determined to be greater than 2000 mg/kg/day, the highest dose tested. In addition, a battery of tests including Ames test, in vitro chromosome aberration assay and in vivo micronucleus assay suggested that the AG extract was not genotoxic. In conclusion, the AG extract appears to be safe as a traditional medicine for oral consumption.

Dibenzoyl and isoflavonoid glycosides from Sophora flavescens: inhibition of the cytotoxic effect of D-galactosamine on human hepatocyte HL-7702

Twelve new dibenzoyl derivatives sophodibenzoside A-L (1-12) and five new isoflavone glycosides (13-17) have been isolated from the roots of Sophora flavescens together with eight known compounds (18-25). Notably, the use of acetic acid-d4 was required to enable identification of the dibenzoyl glycoside structures. Compounds 1, 2, 13, 14, and 19 exhibited weak inhibition of the cytotoxic effect of d-galactosamine on the human hepatic cell line HL-7702.

Identifying 2 prenylflavanones as potential hepatotoxic compounds in the ethanol extract of Sophora flavescens

Zhixue capsule is a prescription for hemorrhoid commonly used in traditional Chinese medicine. This drug was recalled by the State Food and Drug Administration in 2008 because of severe adverse hepatic reactions. Zhixue capsule is composed of ethanol extracts of Cortex Dictamni (ECD) and Sophora flavescens (ESF). In our preliminary study, we observed the hepatotoxic effects of ESF on rat primary hepatocytes. However, ECD did not exhibit hepatotoxicity at the same concentration range. In this study, ESF was evaluated for its potential hepatotoxic effects on rats. Bioassay-guided isolation was used to identify the material basis for hepatotoxicity. Treatment with 1.25 g/kg and 2.5 g/kg ESF significantly elevated the alanine aminotransferase and aspartate aminotransferase levels in the serum. The changes in the levels of transaminases were supported by the remarkable fatty degeneration of liver histopathology. Further investigations using bioassay-guided isolation and analysis indicated that prenylated flavanones accounted for the positive hepatotoxic results. Two isolated compounds were identified, kurarinone and sophoraflavanone G, using nuclear magnetic resonance and mass spectrometry techniques. These compounds have potent toxic effects on primary rat hepatocytes (with IC50 values of 29.9 μM and 16.5 μM) and human HL-7702 liver cells (with IC50 values of 48.2 μM and 40.3 μM), respectively. Consequently, the hepatotoxic constituents of S. flavescens were determined to be prenylated flavanones, kurarinone, and sophoraflavanone G.

Studies on lymphangiogenesis inhibitors from Korean and Japanese crude drugs

Metastasis occurs when cancer cells detach from a tumor, travel to distant sites in the body and develop into tumors in these new locations. Most cancer patients die from metastases. Among the various forms of cancer metastasis, lymphatic metastasis is an important determinant in cancer treatment and staging. In this study, we investigated lymphangiogenesis inhibitors from crude drugs used in Japan and Korea. The three crude drugs Saussureae Radix, Psoraleae Semen and Aurantti Fructus Immaturus significantly inhibited the proliferation of temperature-sensitive rat lymphatic endothelial (TR-LE) cells in vitro. By a chromatographic method using bioassay-guided fractionation methods, costunolide (1) and dehydrocostus lactone (2) from S. Radix, p-hydroxybenzaldehyde (3), psoralen (4), angelicin (5), psoracorylifol D (6), isobavachalone (7), bavachinin (8) Δ(3),2-hydroxybakuchiol (9) and bakuchiol (10) from P. Semen and cis-octadecyl ferulate (11), (2R)-3β,7,4'-trihydroxy-5-methoxy-8-(γ,γ-dimethylallyl)-flavanone (12), (2S)-7,4'-dihydroxy-5-methoxy-8-(γ,γ-dimethylallyl)-flavanone (13) and umbelliferone (14) from A. F. Immaturus were obtained. Three compounds (compounds 11-13) from A. F. Immaturus were isolated for the first time from this medicinal plant. Among isolated compounds, ten compounds (compounds 1, 2, 6-12, 13) showed an inhibitory effect on the proliferation and the capillary-like tube formation of TR-LE cells. In addition, all compounds except compound 12 showed selective inhibition of the proliferation of TR-LE cells compared to Hela and Lewis lung carcinoma (LLC) cells. These compounds might offer clinical benefits as lymphangiogenesis inhibitors and may be good candidates for novel anti-cancer and anti-metastatic agents.

Antibacterial and anti-inflammatory activity of traditional Chinese herb pairs, Angelica sinensis and Sophora flavescens

The purpose of the present study was to investigate the antibacterial and anti-inflammatory activity of Angelica sinensis extract (AE), Sophora flavescens extract (SE), and herb pair A. sinensis and S. flavescens extract (HPE). Endotoxin-induced uveitis (EIU) was induced in rats by a footpad injection of lipopolysaccharide. The anti-inflammatory potential of AE, SE, and HPE in the regulation of nuclear factor kappa B (NF-κB), maleic dialdehyde (MDA), polymorphonuclear cells (PMN), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and tumor necrosis factor-α (TNF-α), adhesion molecule (ICAM-1), and cyclooxygenase-2 (COX-2) was determined by ELISA and immunohistochemistry. HPE showed strong antibacterial activity at all tested concentrations (1.25, 2.5, and 5 μg/ml) to Escherichia coli, Staphylococcus aureus, and Shigella Castellani and Chalmers. HPE significantly inhibited EIU-induced upregulation of NF-κB activation and the production of IL-1β, TNF-α, iNOS, ICAM-1, and COX-2. Moreover, HPE suppressed MDA and infiltration of PMN. The study supports the hypothesis that the antipimple and anti-eczema activities of Dangguikushen compound recipe are attributed to herb pairs, A. sinensis and S. flavescens, used in combination.

Antitumor and immunomodulating activity of a polysaccharide from Sophora flavescens Ait

The immunostimulatory activity of Sophora flavescens polysaccharide (SFPW1) was evaluated by using in vitro cell models and in vivo animal models. The results demonstrated that SFPW1 could effectively inhibit the tumor growth in H22 tumor-bearing mice and promote the splenocyte proliferation, thus resulting in a prolonged life survival. For assay in vitro, SFPW1 significantly strengthened peritoneal macrophages to devour H22 tumor cells and stimulated macrophages to produce nitric oxide (NO) via up-regulation of inducible NO synthase (iNOS) activity. However, no direct cytotoxicity against H22 tumor cells was observed in vitro. These results suggest that SFPW1 might be a strong natural immunomodulator and the antitumor effect of this polysaccharide is associated with its potent immunostimulating effect.

Kinetics and molecular docking studies of kaempferol and its prenylated derivatives as aldose reductase inhibitors

Aldose reductase inhibitors (ARIs) suppressing the hyperglycemia-induced polyol pathway have been provided as potential therapeutic candidates in the treatment and prevention of diabetic complications. Based upon structure-activity relationships of desmethylanhydroicaritin (1) and sophoflavescenol (2) as promising ARIs, 3,4'-dihydroxy flavonols with a prenyl or lavandulyl group at the C-8 position and a hydroxyl or methoxy group at the C-5 position are important for aldose reductase (AR) inhibition. In order to prove the above results, a combination of computational prediction and enzyme kinetics has begun to emerge as an effective screening technique for the potential. In the present study, we predicted the 3D structure of AR in rat and human using a docking algorithm to simulate binding between AR and prenylated flavonoids (1 and 2) and kaempferol (3) and scrutinized the reversible inhibition of AR by these ARIs. Docking simulation results of 1-3 demonstrated negative binding energies (Autodock 4.0=-9.11 to -7.64 kcal/mol; Fred 2.0=-79.54 to -51.84 kcal/mol) and an additional hydrogen bond through Phe122 and Trp219, in addition to the previously proposed interaction of AR and phenolics through Trp20, Tyr48, His110, and Trp111 residues, indicating that the presence of 8-prenyl and 5-methyl groups might potentiate tighter binding to the active site of the enzyme and more effective AR inhibitors. Moreover, types of AR inhibition were different depending on the presence or absence of the 8-prenyl group, in that 1 and 2 are mixed inhibitors with respective Ki values of 0.69 μM and 0.94 μM, while 3 showed noncompetitive inhibition with a Ki value of 4.65 μM. The present study suggests that an effective strategy for screening potential ARIs could be established by predicting 3D structural conformation of prenylated flavonoids and the orientation within the enzyme as well as by simultaneously determining the mode of enzyme inhibition.

Selective Inhibition of Prenylated Flavonoids from Sophora flavescens against BACE1 and Cholinesterases

It was previously reported that certain lavandulylated flavanones from Sophora flavescens are β-site APP cleaving enzyme 1 (BACE1) inhibitors; however, based upon their levels within the extract, their inhibitory effects should be higher than expected. Moreover, chalcones and flavonols were reported to exert higher bioactivities than flavanones. These findings have led to a further search for other possible constituents potentially contributing to the strong inhibitory activity of the S. flavescens extract. In this study, BACE1 activities were significantly inhibited by 8-lavandulylkaempferol (IC50 7.29 μM), kuraridinol (IC50 7.10 μM), kuraridin (IC50 6.03 μM), and kushenol C (IC50 5.45 μM) from the ethyl acetate fraction, along with desmethylanhydroicaritin (IC50 1.86 μM), xanthohumol (IC50 7.19 μM), and leachianone G (IC50 8.56 μM) from the dichloromethane fraction of the extract. The results indicate that the prenyl group, rather than the lavandulyl group, and the flavonols and chalcones, rather than flavanones, might make predominant contributions to BACE1 inhibition. In particular, 8-lavandulylkaempferol exhibited significant inhibitory effects with IC50 values of 7.10 and 8.11 μM for butyrylcholinesterase and acetylcholinesterase, respectively, when compared to its counterpart, desmethylanhydroicaritin. This indicates that the lavandulyl group might play a predominant role in both cholinesterase inhibitions. This is the first study indicating that prenylated flavonoids exert varying degrees of inhibition primarily through their skeleton (flavonols, chalcones, flavanones), as well as their lipophilic chain length (prenyl and lavandulyl groups). Therefore, S. flavescens and its prenylated flavonoids, possessing low molecular weights and lipophilic moieties may be potent preventive and therapeutic candidates for Alzheimer's disease.

Anti-inflammatory effects of fermented and non-fermented Sophora flavescens: a comparative study

Background

The roots of Sophora flavescens (Leguminosae) have been used in East Asian countries as an herbal medicine and a food ingredient for thousands of years. The aim of the present study was to investigate the effects of S. flavescens fermentation on endotoxin-induced uveitis (EIU) in rats.

Methods

EIU was induced in rats via a footpad injection of lipopolysaccharide (LPS). Immediately after the LPS inoculation, fermented and non-fermented extracts of S. flavescens (FSE and NFSE, respectively) were administered orally, and the aqueous humor was collected from both eyes 24 hours later. The anti-inflammatory effects of FSE and NFSE were examined in terms of regulation of nuclear factor kappa B (NF-κB) activation and the expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), intercellular cell adhesion molecule (ICAM)-1, and cyclooxygenase-2 (COX-2). The regulation of maleic dialdehyde (MDA) levels and polymorphonuclear cell (PMN) infiltration by FSE and NFSE were also examined.

Results

Treatment with FSE significantly inhibited LPS-induced increases in IL-1β and TNF-α production and the expression of iNOS, ICAM-1 and COX-2. Moreover, FSE suppressed LPS-induced NF-κB activation, and reduced both MDA levels and infiltration by PMN.

Conclusion

These results indicate that solid state fermentation may enhance the anti-inflammatory effects of S. flavescens.

Synthesis and antioxidant activity of long chain alkyl hydroxycinnamates

Long chain alkyl hydroxycinnamates (8-21) were synthesized from the corresponding half esters of malonic acid (5-7) and benzaldehyde derivatives by Knoevenagel condensation. The total antioxidant capacity of these hydroxycinnamyl esters was evaluated using DPPH and ABTS assays. The observed antioxidant activity was highest for esters of caffeic acid followed by sinapic esters and ferulic esters. The parameters for drug-likeness of these hydroxycinnamyl esters were also evaluated according to the Lipinski's 'rule-of-five'. All the ester derivatives were found to violate one of the Lipinski's parameters (cLogP>5), even though they have been found to be soluble in protic solvents. The predictive topological polar surface area (TPSA) data allow concluding that they could have a good capacity for penetrating cell membranes. Therefore, one can propose these novel lipophilic compounds as potential antioxidants for tackling oxidative processes.

8-Prenylkaempferol accelerates osteoblast maturation through bone morphogenetic protein-2/p38 pathway to activate Runx2 transcription

AIMS

In this study, we investigated the effect of 8-prenylkaempferol (8-PK), a prenyl-flavonoid isolated from Sophora flavescens, on osteoblast differentiation and maturation.

MAIN METHODS

MC3T3-E1 cells were exposed to 8-PK and the cytotoxicity was assayed. Osteoblast differentiation and maturation were evaluated by analyzing alkaline phosphatase (ALP) activity and cell mineralization, respectively. RT-PCR and Western blot were executed to determine the effects of 8-PK on osteoblast differentiation-related gene expression and signaling pathway.

KEY FINDINGS

8-PK significantly promoted ALP activity, up-regulated mRNA expressions of osteocalcin, osteopontin, and type I collagen, and induced bone nodules formation. Induction of differentiation by 8-PK was associated with increased bone morphogenetic protein (BMP)-2 expression, and sequentially up-regulated the phosphorylations of Smad1/5/8 and p38, and increased the nuclear translocation of runt-related transcription factor 2 (Runx2). Addition of BMP-2 antagonist noggin blocked 8-PK and recombinant mouse BMP-2-induced ALP activity, reconfirming that BMP-2 production is required in 8-PK-mediated osteoblast differentiation. Noggin also abrogated 8-PK evoked phosphorylations of Smad1/5/8 and p38, suggesting that BMP-2 signaling is required for p38 activation in 8-PK-treated cells. Application of p38 inhibitor SB203580 repressed not only 8-PK-mediated activation of ALP, but also the nuclear translocation of Runx2 and bone nodules formation.

SIGNIFICANCE

The present results suggested that BMP-2/p38/Runx2 pathways were involved in 8-PK-induced differentiation/maturation of MC3T3-E1 osteoblasts and firstly demonstrated that 8-PK might be a promising agent for inducing osteogenesis.

Medicinal herbal extracts of Sophorae radix, Acanthopanacis cortex, Sanguisorbae radix and Torilis fructus inhibit coronavirus replication in vitro

BACKGROUND

Cimicifuga rhizome, Meliae cortex, Coptidis rhizome and Phellodendron cortex have been previously shown to exhibit anti-coronavirus activity. Here, an additional 19 traditional medicinal herbal extracts were evaluated for antiviral activities in vitro.

METHODS

A plaque assay was used to evaluate the effects of 19 extracts, and the concentration of extract required to inhibit 50% of the replication (EC(50)) of mouse hepatitis virus (MHV) A59 strain (MHV-A59) was determined. The 50% cytotoxic concentration (CC(50)) of each extract was also determined. Northern and western blot analyses were conducted to evaluate antiviral activity on viral entry, viral RNA and protein expression, and release in MHV-infected DBT cells.

RESULTS

Sophorae radix, Acanthopanacis cortex and Torilis fructus reduced intracellular viral RNA levels with comparable reductions in viral proteins and MHV-A59 production. The extracts also reduced the replication of the John Howard Mueller strain of MHV, porcine epidemic diarrhoea virus and vesicular stomatitis virus in vitro. Sanguisorbae radix reduced coronavirus production, partly as a result of decreased protein synthesis, but without a significant reduction in intracellular viral RNA levels. The EC(50) values of the four extracts ranged from 0.8 to 3.7 microg/ml, whereas the CC(50) values ranged from 156.5 to 556.8 microg/ml. Acanthopanacis cortex and Torilis fructus might exert their antiviral activities in MHV-A59-infected cells by inducing cyclooxygenase-2 expression via the activation of extracellular signal-related kinase (ERK) and p38 or ERK alone, respectively.

CONCLUSIONS

Sophorae radix, Acanthopanacis cortex, Sanguisorbae radix and Torilis fructus might be considered as promising novel anti-coronavirus drug candidates.

Protective effects of Korean mistletoe lectin on radical-induced oxidative stress

The radical scavenging effects and protective activities against oxidative stress of Korean mistletoe (Viscum album coloratum) lectin were investigated in vitro and with a cellular system using LLC-PK(1) renal epithelial cells. The Korean mistletoe lectin (KML) showed 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with an IC(50) value of 42.6 microg/ml. It also exerted nitric oxide (NO), superoxide anion (O(2)(-)), and hydroxyl radical scavenging activities in concentration-dependent manners. These results suggest that KML is a promising antioxidant by scavenging free radicals. Furthermore, under the LLC-PK(1) cellular model, the cells showed declines in viability and increases in lipid peroxidation through oxidative stress induced by sodium nitroprusside (SNP) and pyrogallol, generators of NO and O(2)(-), respectively. However, KML significantly and dose-dependently inhibited cell cytotoxicity and lipid peroxidation. In addition, 3-morpholinosydnonimnie (SIN-1), a generator of peroxynitrite (ONOO(-)) formed by simultaneously releases of NO and O(2)(-), caused cytotoxicity, lipid peroxidation, and NO overproduction in the LLC-PK(1) cells while KML ameliorated ONOO(-)-induced oxidative damage. Furthermore, overexpressions of cyclooxygenase-2 and inducible NO synthase induced by SIN-1 were observed, but KML down-regulated the expression levels of both genes. KML also reduced SIN-1-induced nuclear factor kappa B expression and the phosphorylation of inhibitor kappa B alpha in LLC-PK(1) cells. These results indicate that KML has protective activities against oxidative damage induced by free radicals.

Inhibitory activities of prenylated flavonoids from Sophora flavescens against aldose reductase and generation of advanced glycation endproducts

Important targets for the prevention and treatment of diabetic complications include aldose reductase (AR) inhibitors (ARIs) and inhibitors of advanced glycation endproduct (AGE) formation. Here we evaluate the inhibitory activities of prenylated flavonoids isolated from Sophora flavescens, a traditional herbal medicine, on rat lens AR (RLAR), human recombinant AR (HRAR) and AGE formation. Among the tested compounds, two prenylated chalcones — desmethylanhydroicaritin (1) and 8-lavandulylkaempferol (2) — along with five prenylated flavanones — kurarinol (8), kurarinone (9), (2S)-2′-methoxykurarinone (10), (2S)-3β,7,4′-trihydroxy-5-methoxy-8-(γ,γ-dimethylally)-flavanone (11), and kushenol E (13) were potent inhibitors of RLAR, with IC50 values of 0.95, 3.80, 2.13, 2.99, 3.77, 3.63 and 7.74 μM, respectively, compared with quercetin (IC50 7.73 μM). In the HRAR assay, most of the prenylated flavonoids tested showed marked inhibitory activity compared with quercetin (IC50 2.54 μM). In particular, all tested prenylated flavonols, such as desmethylanhydroicaritin (1, IC50 0.45 μM), 8-lavandulylkaempferol (2, IC50 0.79 μM) and kushenol C (3, IC50 0.85 μM), as well as a prenylated chalcone, kuraridin (5, IC50 0.27 μM), and a prenylated flavanone, (2S)-7,4′-dihydroxy-5-methoxy-8-(γ,γ-dimethylally)-flavanone (12, IC50 0.37 μM), showed significant inhibitory activities compared with the potent AR inhibitor epalrestat (IC50 0.28 μM). Interestingly, prenylated flavonoids 1 (IC50 104.3 μgmL−1), 2 (IC50 132.1 μgmL−1), 3 (IC50 84.6 μgmL−1) and 11 (IC50 261.0 μgmL−1), which harbour a 3-hydroxyl group, also possessed good inhibitory activity toward AGE formation compared with the positive control aminoguanidine (IC50 115.7 μgmL−1). Thus, S. flavescens and its prenylated flavonoids inhibit the processes that underlie diabetic complications and related diseases and may therefore have therapeutic benefit.

Anti-Inflammatory and antiproliferative activities of trifolirhizin, a flavonoid from Sophora flavescens roots

Trifolirhizin, a pterocarpan flavonoid, was isolated from the roots of Sophora flavescens, and its chemical structure was confirmed by (1)H and (13)C NMR and MS spectra. Its anti-inflammatory activity was examined in lipopolysaccharide (LPS)-stimulated mouse J774A.1 macrophages. Trifolirhizin not only dose-dependently inhibited LPS-induced expression of pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) but also inhibited lipopolysaccharide (LPS)-induced expression of cyclooxygenase-2 (COX-2). In addition, trifolirhizin showed in vitro inhibitory effects on the growth of human A2780 ovarian and H23 lung cancer cells. These results suggest that trifolirhizin possesses potential anti-inflammatory and anticancer activities.

Fundamentals and Health Benefits of Xanthohumol, a Natural Product Derived from Hops and Beer

In recent years, there has been a growing interest in phenolic compounds and their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. Xanthohumol, a prenylated chalcone from hops and beer, is among the phenolic compounds which have received the most attention in recent years. This compound has a range of interesting biological properties that may have therapeutic utility. Based on the health-promoting properties of xanthohumol, the production of a beer enriched in this substance would be of huge interest to the brewing industry, for the benefits this could bring to consumer's health. This paper reviews recent and important data with respect to the health benefits or biological activities of xanthohumol and beer. In addition, an overview of the chemistry and biotechnological aspects of xanthohumol is presented.

Antioxidants from the Leaf Extract of Byrsonima Bucidaefolia

The radical scavenging assay-guided fractionation of the leaf extract of Byrsonima bucidaefolia Standl. yielded two metabolites with antioxidant activity, identified as methyl gallate (1) and methyl m-trigallate (2) on the basis of their spectroscopic data. Both 1 and 2 were identified as artifacts of the extraction and/or the purification process, possibly resulting from transesterification of precursor gallotannins. Evaluation of the antioxidant activity of both the isolated metabolites 1 and 2 and three of their derivatives (3-5), showed that 1 and 2 have a stronger antioxidant activity than vitamin C when tested using the DPPH reduction assay.

Desmethylanhydroicaritin inhibits NF-kappaB-regulated inflammatory gene expression by modulating the redox-sensitive PI3K/PTEN/Akt pathway

We investigated the effect of desmethylanhydroicaritin (DMAI), a major compound of the Chinese herbal medicine Epimedium, on inflammatory gene expression and the NF-kappaB signaling pathway. We found that DMAI suppressed the expression of NF-kappaB-responsive genes, such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-1beta, and tumor necrosis factor-alpha, in lipopolysaccharide (LPS)-stimulated macrophages and endotoxemic mice as well as protected mice against LPS-induced lethality. DMAI inhibited NF-kappaB activation through the inhibition of IkappaB kinase (IKK) activation, IkappaB phosphorylation and degradation, and NF-kappaB nuclear translocation in LPS-stimulated macrophages. This compound inhibited in vitro and in vivo LPS-induced phosphatidylinositol 3-kinase (PI3K) activation, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) oxidation, and Akt phosphorylation, which are upstream modulators of IKK activation. Moreover, treatment with DMAI was not observed to affect the interaction between the Toll-like receptor 4, MyD88, and TRAF6 as well as mitogen-activated protein kinase activation. DMAI also suppressed intracellular H(2)O(2) accumulation, hydroxyl radical production, and glutathione oxidation without affecting superoxide generation and accumulation by NADPH oxidase. Moreover, DMAI inhibited redox-sensitive activation of the PI3K/PTEN/Akt pathway and NF-kappaB activation in macrophages treated with H(2)O(2). These results indicate that DMAI negatively regulates canonical NF-kappaB-regulated inflammatory gene expression by functioning as an inhibitor of the NF-kappaB pathway through the suppression of redox-based PI3K activation and PTEN inactivation and therefore can be considered as a potential drug for inflammatory diseases.

Inhibitory effects of kurarinol, kuraridinol, and trifolirhizin from Sophora flavescens on tyrosinase and melanin synthesis

Previously, it was reported that some prenylated flavonoids contained in the dichloromethane fraction of the ethanolic extract of Sophora flavescens, such as kuraridin, sophoraflavanone G, kurarinone, and kushenol F, are tyrosinase inhibitors; however, based on the level of these inhibitors in the extract, its inhibitory effect on tyrosinase activity was higher than expected. This has led us to further investigate other possible constituents that may contribute to the extract's strong inhibitory activity. The results of this study indicate that kurarinol (1), kuraridinol (2), and trifolirhizin (3), from the ethyl acetate fraction of Sophora extract, can inhibit tyrosinase activity. Compared with kojic acid (16.22+/-1.71 microM), compounds 1-3 possessed potent tyrosinase inhibitory activity with IC(50) values of 8.60+/-0.51, 0.88+/-0.06, and 506.77+/-4.94 microM, respectively. These three compounds were further tested for their inhibitory effects on melanogenesis. In cultured B16 melanoma cells, 1-3 markedly inhibited (>50%) melanin synthesis at 50 microM. This is the first study indicating that 1-3 exert varying degrees of inhibition on tyrosinase-dependent melanin biosynthesis, and therefore, are candidates as skin-whitening agents.

A new lavandulylated flavonoid with free radical and onoo-scavenging activities fromSophora flavescens

A new lavandulylated flavonoid, 8-lavandulylkaempferol (1), was isolated from the roots of Sophora flavescens AITON (Leguminosae). The structure of this compound was determined via spectroscopic analysis. Compound 1 was determined to be a scavenger on both 1,1-diphenyl-2-picrylhydrazyl radicals and ONOO-.