Butein (3,4,2',4'-tetrahydroxychalcone) ameliorates experimental anti-glomerular basement membrane antibody-associated glomerulonephritis (3)

Butein Ameliorates Oxidative Stress in H9c2 Cardiomyoblasts through Activation of the NRF2 Signaling Pathway

Oxidative stress, defined as an imbalance between reactive oxygen species (ROS) production and the antioxidant defense system, contributes to the pathogenesis of many heart diseases. Therefore, oxidative stress has been highlighted as a therapeutic target for heart disease treatment. Butein, a tetrahydroxychalcone, has potential biological activities, especially antioxidant properties. However, the effect of butein on oxidative-stressed heart cells has been poorly studied. Thus, we sought to identify the antioxidant effects of butein in H9c2 cardiomyoblasts. To elucidate these antioxidant effects, various concentrations of butein were used to pretreat H9c2 cells prior to H₂O₂ treatment. Thereafter, measures of oxidative damages, such as ROS production, antioxidant expression levels, and apoptosis, were evaluated. Butein effectively increased cell viability and rescued the cells from oxidative damage through the inhibition of ROS production, apoptosis, and increased antioxidant expression. Furthermore, butein dramatically inhibited mitochondrial dysfunction and endoplasmic reticulum (ER) stress, which are the main ROS inducers. Nrf2 protein translocated from the cytosol to the nucleus and consequently activated its target genes as oxidative stress suppressors. These findings demonstrate that butein has potential antioxidant effects in H9c2 cardiomyoblasts, suggesting that it could be used as a therapeutic substance for the treatment of cardiac diseases.

Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals

Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.

Butein in health and disease: A comprehensive review

BACKGROUND

The risk of suffering from many chronic diseases seems to have made no improvement despite the advancement in medications available in the modern world. Moreover, the use of synthetic chemicals as medications has proved to worsen the scenario due to the various adverse side effects associated with them.

PURPOSE

Extensive research on natural medicines provides ample evidence on the safety and efficacy of phytochemicals and nutraceuticals against diverse chronic ailments. Therefore, it is advisable to use natural products in the management of such diseases. This article aims to present a comprehensive and critical review of known pharmacological and biological effects of butein, an important chalcone polyphenol first isolated from Rhus verniciflua Stokes, implicated in the prevention and treatment of various chronic disease conditions.

METHODS

An extensive literature search was conducted using PubMed, ScienceDirect, Scopus and Web of Science^TM core collections using key words followed by evaluation of the bibliographies of relevant articles.

RESULTS

Butein has been preclinically proven to be effective against several chronic diseases because it possesses a wide range of biological properties, including antioxidant, anti-inflammatory, anticancer, antidiabetic, hypotensive and neuroprotective effects. Furthermore, it has been shown to affect multiple molecular targets, including the master transcription factor nuclear factor-κB and its downstream molecules. Moreover, since it acts on multiple pathways, the chances of non-responsiveness and resistance development is reduced, supporting the use of butein as a preferred treatment option.

CONCLUSION

Based on numerous preclinical studies, butein shows significant therapeutic potential against various diseases. Nevertheless, well-designed clinical studies are urgently needed to validate the preclinical findings.

Butein and Its Role in Chronic Diseases

Natural compounds isolated from various plant sources have been used for therapeutic purpose for centuries. These compounds have been routinely used for the management of various chronic ailments and have gained considerable attention because of their significant efficacy and comparatively low side effects. Butein, a chacolnoid compound that has been isolated from various medicinal plants has exhibited a wide range of beneficial pharmacological effects, such as anti-inflammatory, anticancer, antioxidant, and anti-angiogenic in diverse disease models. This article briefly summarizes the past published literature related to the therapeutic and protective effects of butein, as demonstrated in various models of human chronic diseases. Further analysis of its important cellular targets, toxicity, and pharmacokinetic profile may further significantly expand its therapeutic application.

Butein suppresses ICAM-1 expression through the inhibition of IκBα and c-Jun phosphorylation in TNF-α- and PMA-treated HUVECs

Butein (3,4,2',4'-tetrahydroxychalcone), a flavonoid derivative, has been reported to show several biological actions, including anti-inflammatory and anti-cancer. However, the possible molecular mechanisms involved are poorly understood. Treatment of human umbilical vein endothelial cells (HUVECs) with butein significantly inhibited cell surface intercellular adhesion molecule-1 (ICAM-1) expression, ICAM-1 protein synthesis, and mRNA expression induced by tumor necrotic factor-α (TNF-α) and/or phorbol 12-myristate 13-acetate (PMA). Electrophoretic mobility shift assay revealed that butein blocked activation of transcription factors, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), induced by TNF-α and PMA. Moreover, butein abolished TNF-α- and PMA-induced IκBα phosphorylation, which participates in NF-κB activation, and PMA-induced phosphorylation of c-Jun, a subunit composed of AP-1. In vitro, butein inhibited the phosphorylation of c-Jun, binding to GST beads, mediated by JNK isolated from PMA-treated cells. The inhibitory action of butein on the JNK-mediated in vitro c-Jun phosphorylation was abrogated in the presence of ATP. These results indicate that in HUVECs, butein suppresses the expression of ICAM-1 mRNA and protein through the inhibition of the activation of NF-κB and AP-1 induced by TNF-α and PMA, that the inhibitory action of butein on NF-κB activation results from the inhibition of IκBα phosphorylation by IκB kinase (IKK), and that the inactivation of PMA-activated AP-1 by butein is due to the blocking of JNK-mediated c-Jun phosphorylation through the inhibition of ATP binding.

Targeting the STAT3 signaling pathway in cancer: role of synthetic and natural inhibitors

Signal transducers and activators of transcription (STATs) comprise a family of cytoplasmic transcription factors that mediate intracellular signaling that is usually generated at cell surface receptors and thereby transmit it to the nucleus. Numerous studies have demonstrated constitutive activation of STAT3 in a wide variety of human tumors, including hematological malignancies (leukemias, lymphomas, and multiple myeloma) as well as diverse solid tumors (such as head and neck, breast, lung, gastric, hepatocellular, colorectal and prostate cancers). There is strong evidence to suggest that aberrant STAT3 signaling promotes initiation and progression of human cancers by either inhibiting apoptosis or inducing cell proliferation, angiogenesis, invasion, and metastasis. Suppression of STAT3 activation results in the induction of apoptosis in tumor cells, and accordingly its pharmacological modulation by tyrosine kinase inhibitors, antisense oligonucleotides, decoy nucleotides, dominant negative proteins, RNA interference and chemopreventive agents have been employed to suppress the proliferation of various human cancer cells in culture and tumorigenicity in vivo. However, the identification and development of novel drugs that can target deregulated STAT3 activation effectively remains an important scientific and clinical challenge. This review presents the evidence for critical roles of STAT3 in oncogenesis and discusses the potential for development of novel cancer therapies based on mechanistic understanding of STAT3 signaling cascade.

The role of chalcones in suppression of NF-κB-mediated inflammation and cancer

Although consumption of fruits, vegetables, spices, cereals and pulses has been associated with lower incidence of cancer and other chronic diseases, how these dietary agents and their active ingredients minimize these diseases, is not fully understood. Whether it is oranges, kawa, hops, water-lilly, locorice, wax apple or mulberry, they are all connected by a group of aromatic ketones, called chalcones (1,3-diaryl-2-propen-1-ones). Some of the most significant chalcones identified from these plants include flavokawin, butein, xanthoangelol, 4-hydroxyderricin, cardamonin, 2',4'-dihydroxychalcone, isoliquiritigenin, isosalipurposide, and naringenin chalcone. These chalcones have been linked with immunomodulation, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, anticancer, and antidiabetic activities. The current review, however, deals with the role of various chalcones in inflammation that controls both the immune system and tumorigenesis. Inflammatory pathways have been shown to mediate the survival, proliferation, invasion, angiogenesis and metastasis of tumors. How these chalcones modulate inflammatory pathways, tumorigenesis and immune system is the focus of this review.

Suppression of signal transducer and activator of transcription 3 activation by butein inhibits growth of human hepatocellular carcinoma in vivo

PURPOSE

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third cause of global cancer mortality. Increasing evidence suggest that STAT3 is a critical mediator of oncogenic signaling in HCC and controls the expression of several genes involved in proliferation, survival, metastasis, and angiogenesis. Thus, the novel agents that can suppress STAT3 activation have potential for both prevention and treatment of HCC.

EXPERIMENTAL DESIGN

The effect of butein on STAT3 activation, associated protein kinases, STAT3-regulated gene products, cellular proliferation, and apoptosis was investigated. The in vivo effect of butein on the growth of human HCC xenograft tumors in male athymic nu/nu mice was also examined.

RESULTS

We tested an agent, butein, for its ability to suppress STAT3 activation in HCC cells and nude mice model along with prospectively testing the hypothesis of STAT3 inhibition in a virtual predictive functional proteomics tumor pathway technology platform. We found that butein inhibited both constitutive and inducible STAT3 activation in HCC cells. The suppression was mediated through the inhibition of activation of upstream kinases c-Src and Janus-activated kinase 2. Butein inhibited proliferation and significantly potentiated the apoptotic effects of paclitaxel and doxorubicin in HCC cells. When administered intraperitoneally, butein inhibited the growth of human HCC xenograft tumors in male athymic nu/nu mice.

CONCLUSIONS

Overall, cumulative results from experimental and predictive studies suggest that butein exerts its antiproliferative and proapoptotic effects through suppression of STAT3 signaling in HCC both in vitro and in vivo.

Modulation of ovine neutrophil function and apoptosis by standardized extracts of Echinacea angustifolia, Butea frondosa and Curcuma longa

Impaired neutrophil function has been associated with increased infectious diseases in ruminants. Attachment of neutrophils to endothelium and superoxide production is critical features of their immune activity. Once the infection is cleared, programmed cell death ensures the rapid resolution of inflammation. To develop new natural therapeutics for ruminants, standard extracts of Echinacea angustifolia (Polinacea), Butea frondosa and Curcuma longa (Curcuvet) were first evaluated on ovine neutrophil functions. Curcuvet strongly reduced PMA-stimulated adhesion and superoxide production. Polinacea and B. frondosa extract also reduced these functions, but with less efficacy than Curcuvet. We analyzed the effect of extracts on spontaneous apoptosis and gene expression in neutrophils aged in vitro for up to 22h. IL8 is critical for neutrophil recruitment and the immune response; Bcl2-related proteins, Bcl2A1 and Bax, are key regulators of neutrophil fate. Spontaneous apoptosis strongly increased in ovine neutrophils cultured for 22h (T22), accompanied by an upregulation of IL8 and a decreased Bcl2A1:Bax ratio. Curcuvet stimulated spontaneous apoptosis and inhibited IL8 and Bcl2A1 gene expression at T22, whereas Polinacea and B. frondosa extract inhibited spontaneous apoptosis and stimulated IL8 expression at T22. These results suggest that Curcuvet has antiinflammatory activity, whereas Polinacea and B. frondosa have an immunomodulatory action on sheep neutrophils.

Antimicrobial and antioxidative activities of bioactive constituents from Hydnophytum formicarum Jack

Hydnophytum formicarum Jack. (Rubiaceae) is a medicinal plant whose tubers possesses cardiovascular, anti-inflammatory and antiparasitic effects and have been used for the treatment of hepatitis, rheumatism and diarrhea. Herein we report the isolation of its active constituents and the testing of their antimicrobial activity against 27 strains of microorganisms using an agar dilution method and of their antioxidative activity using the DPPH and SOD assays. The results show that the crude hexane, dichloromethane, ethyl acetate and methanol extracts exert such activities. Particularly, the crude ethyl acetate extract exhibits antigrowth activity against many Gram-positive and Gram-negative bacteria with MIC 256 μg/mL. Shewanella putrefaciens ATCC 8671 is completely inhibited at a lower MIC (128 μg/mL). Interestingly, Corynebacterium diphtheriae NCTC 10356 is inhibited by all the tested extracts. Significantly, the ethyl acetate extract is also the most potent antioxidant, showing 83.31% radical scavenging activity with IC₅₀ 8.40 μg/mL in the DPPH assay. The other extracts display weak to moderate antioxidative activities, ranging from 28.60-56.80% radical scavenging. The SOD assay shows that methanol extract exhibits the highest activity (74.19% inhibition of superoxide radical). The dichloromethane and ethyl acetate extracts display comparable SOD activity. The promising bioactivities of the crude ethyl acetate extract guided the first isolation of bioactive flavonoid and phenolic compounds: isoliquiritigenin (2), protocatechualdehyde (3), butin (4) and butein (5) from this species. Their structures have been fully established by 1D and 2D NMR. In addition, stigmasterol was isolated from the crude hexane and dichloromethane extracts. The antimicrobial and cytotoxic activities of compounds 3-5 were evaluated. The tested compounds were inactive against HuCCA-1 and KB cell lines, showing ED₅₀> 10 μg/mL. Protocatechualdehyde (3) completely inhibits the growth of Plesiomonas shigelloides with MIC ≤60 μg/mL. As a result, we propose that Hydnophytum formicarum Jack. can serve as a new source enriched with potent antioxidative and antimicrobial agents.

Butein, a tetrahydroxychalcone, inhibits nuclear factor (NF)-kappaB and NF-kappaB-regulated gene expression through direct inhibition of IkappaBalpha kinase beta on cysteine 179 residue

Although butein (3,4,2',4'-tetrahydroxychalcone) is known to exhibit anti-inflammatory, anti-cancer, and anti-fibrogenic activities, very little is known about its mechanism of action. Because numerous effects modulated by butein can be linked to interference with the NF-kappaB pathway, we investigated in detail the effect of this chalcone on NF-kappaB activity. As examined by DNA binding, we found that butein suppressed tumor necrosis factor (TNF)-induced NF-kappaB activation in a dose- and time-dependent manner; suppressed the NF-kappaB activation induced by various inflammatory agents and carcinogens; and inhibited the NF-kappaB reporter activity induced by TNFR1, TRADD, TRAF2, NIK, TAK1/TAB1, and IKK-beta. We also found that butein blocked the phosphorylation and degradation of IkappaBalpha by inhibiting IkappaBalpha kinase (IKK) activation. We found the inactivation of IKK by butein was direct and involved cysteine residue 179. This correlated with the suppression of phosphorylation and the nuclear translocation of p65. In this study, butein also inhibited the expression of the NF-kappaB-regulated gene products involved in anti-apoptosis (IAP2, Bcl-2, and Bcl-xL), proliferation (cyclin D1 and c-Myc), and invasion (COX-2 and MMP-9). Suppression of these gene products correlated with enhancement of the apoptosis induced by TNF and chemotherapeutic agents; and inhibition of cytokine-induced cellular invasion. Overall, our results indicated that antitumor and anti-inflammatory activities previously assigned to butein may be mediated in part through the direct inhibition of IKK, leading to the suppression of the NF-kappaB activation pathway.

Simultaneous determination of 10 major flavonoids in Dalbergia odorifera by high performance liquid chromatography

A reversed-phase liquid chromatographic method was developed for the simultaneous quantification of 10 major flavonoids, namely butin, (3R)-4'-methoxy-2',3,7-trihydroxyisoflavanone, liquiritigenin, melanettin, violanone, vistitone, formononetin, dalbergin, sativanone and medicarpin in the heartwood of Dalbergia odorifera, an important traditional Chinese medicine. Samples were extracted with 60% methanol. The optimal conditions of separation and detection were achieved on an Agilent Zorbax SB-C18 column (250 mm x 4.6 mm, 5 microm) with a gradient of acetonitrile and 0.3% (v/v) aqueous acetic acid, at a flow rate of 0.8 ml/min, detected at 275 nm. The complete separation was obtained within 55 min for the 10 target compounds. All calibration curves showed good linearity (r2>0.999) within test ranges. The assay was reproducible with overall intra- and inter-day variation of less than 3%. The mean recovery of the method was 100+/-10%, with R.S.D. less than 5%. The current assay method was considered to be suitable for the quality control of D. odorifera samples and could be readily utilized for the determination of the active principles present in this medicinal herb.

The plant polyphenol butein inhibits testosterone-induced proliferation in breast cancer cells expressing aromatase

Chalcones are precursor compounds for flavonoid synthesis in plants, and they can also be synthesized in laboratory. Previous study has documented some of the pharmacological applications of these compounds. Estrogen has long been associated with the initiation and promotion of breast cancer. Inhibiting estrogen synthesis can be effective in the prevention and treatment of the disease. Since most breast cancers received estrogen supplied from local tissues, we employed a breast cancer cell line expressing aromatase to screen for the inhibitory potentials of five hydroxychalcones, i.e. 2-hydroxychalcone, 2'-hydroxychalcone, 4-hydroxychalcone, 4,2',4'-trihydroxy-chalcone (isoquiritigenin), 3,4,2',4'-tetrahydroxychalcone (butein). In the preliminary results, butein was found to be the strongest inhibitor among the tested compounds, and its IC(50) value was 3.75 microM. Subsequent enzyme kinetic study revealed that butein acted on aromatase with a mixed type of inhibition and the K(i) value was determined to be 0.32 microM. Cell proliferation assay indicated that the cell number increased by 10 nM-testosterone treatment was significantly reduced by 5 microM butein, and the administration of flutamide could not reverse the effect. The present study illustrated that butein was an aromatase inhibitor and a potential natural alternative for the chemoprevention or therapy of breast cancer.

Hydroxychalcones exhibit differential effects on XRE transactivation

Chalcones are phenolic compounds that can be isolated from plants. Previous studies have described some pharmacological applications for these compounds. Making use of our established reporter gene system, we determined the effect of five hydroxychalcones--2-hydroxychalcone, 2'-hydroxychalcone, 4-hydroxychalcone, 4,2',4'-trihydroxychalcone, and 3,4,2',4'-tetrahydroxychalcone--on the cellular xenobiotic responsive element (XRE)-transactivation. The interference of chalcones acting against polycyclic aromatic hydrocarbon (PAH)-DNA binding was also examined. Enzyme inhibition assays of cytochrome P450 (CYP) 1A1 and CYP1B1 were initially performed on recombinant protein expressed in insect microsomes. 2'-Hydroxychalcone and 2-hydroxychalcone were the most effective among the tested hydroxychalcones. The two hydroxychalcones had comparable IC50 values for CYP1A1 and CYP1B1, which were determined to be at the micromolar and submicromolar range, respectively. However, reporter gene assays indicated that 2'-hydroxychalcone suppressed XRE-transactivation, whereas 2-hydroxychalcone induced it when 7,12-dimethylbenz[a]anthracene (DMBA) was co-administered. In the absence of DMBA, 10 microM 2-hydroxychalcone and 2'-hydroxychalcone increased XRE-transactivation by 18- and 2.5-fold, respectively, while other chalcones did not significantly alter the response. Cultures treated with the two hydroxychalcones also displayed separate trends in ethoxyresorufin-O-deethylase (EROD) activity and DMBA-DNA covalent binding. In summary, the present study illustrated that the inhibition of hydroxychalcone on CYP1 enzymes and XRE-transactivation was affected by the position and number of hydroxyl groups in its structure.

Determination of butein in rat serum by high performance liquid chromatography

A simple high performance liquid chromatography (HPLC) method was developed for the determination of butein in rat serum. The method involved the deproteinization followed by injection into a Luna C8 column. Butein was eluted at 3.8 min at a flow rate of 0.2 ml/min with the mobile phase of acetonitrile-ammonium formate (10mM, pH 3.0) (35:65, v/v). The standard curve was linear (r(2)=0.995) over the concentration range of 0.1-10 microg/ml. The coefficient of variation (CV) of intra- and inter-assay ranged from 2.7 to 7.5% and 6.0 to 7.5%, respectively. The limit of quantification was 0.1 microg/ml using a serum sample of 50 microl. This method was applied to a pharmacokinetic study after intravenous injection of butein (5mg/kg) to rats.

2'-hydroxychalcone inhibits nuclear factor-kappaB and blocks tumor necrosis factor-alpha- and lipopolysaccharide-induced adhesion of neutrophils to human umbilical vein endothelial cells

Inhibition of expression of cell adhesion molecules (CAM), including intercellular CAM-1 (ICAM-1), vascular CAM-1 (VCAM-1), and E-selectin, has been shown to be important in controlling various inflammatory diseases. The cell adhesion proteins are induced by various inflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-1, and bacterial lipopolysaccharide. The induction process primarily takes place at the level of transcription, where nuclear factor-kappaB (NF-kappaB) plays a major role. We demonstrate here that 2'-hydroxychalcone inhibits the adhesion of peripheral neutrophils to the endothelial cell monolayers by inhibiting the expression of ICAM-1, VCAM-1, and E-selectin in a concentration-dependent manner. The inhibition by 2'-hydroxychalcone is reversible. 2'-hydroxychalcone inhibits the induction of steady-state transcript levels of ICAM-1, VCAM-1, and E-selectin by tumor necrosis factor-alpha as determined by reverse transcription-polymerase chain reaction, and therefore it may interfere with the transcription of their genes. Because NF-kappaB is a major transcription factor involved in CAM expression, we studied its status in the 2'-hydroxychalcone treated cells. We demonstrate that 2'-hydroxychalcone inhibits the activation of NF-kappaB. These results have implications for using NF-kappaB inhibitors for the treatment of various inflammatory diseases.