Brazilin Actuates Ferroptosis in Breast Cancer Cells via p53/SLC7A11/GPX4 Signaling Pathway

OBJECTIVE

To investigate the mechanism of induction of ferroptosis by brazilin in breast cancer cells.

METHODS

Breast cancer 4T1 cells were divided into 6 groups: control, brazilin 1/2 half maximal inhibitory concentration (IC50), IC50, 2×IC50, erastin (10 µg/mL) and capecitabine (10 µg/mL) groups. The effect of brazilin on the proliferation of 4T1 cells was detected by cell counting kit-8 assay, and the treatment dose of brazilin was screened. The effect of brazilin on the mitochondrial morphology of 4T1 cells, and the mitochondrial damage was evaluated under electron microscopy. The levels of Fe2+, reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase 4 (GPX4) were estimated using various detection kits. The invasion and migration abilities of 4T1 cells were detected by scratch assay and transwell assay. The expressions levels of tumor protein p53, solute carrier family 7 member 11 (SLC7A11), GPX4 and acyl-CoA synthetase long-chain family member 4 (ACSL4) proteins were quantified by Western blot assay.

RESULTS

Compared to the control group, the 10 (1/2 IC50), 20 (IC50) and 40 (2×IC50) µg/mL brazilin, erastin, and capecitabine groups showed a significant decrease in the cell survival rate, invasion and migration abilities, GSH, SLC7A11 and GPX4 protein expression levels, and mitochondrial volume and ridge (P<0.05), and a significant increase in the mitochondria membrane density, Fe2+, ROS and MDA levels, and p53 and ACSL4 protein expression levels (P<0.05).

CONCLUSIONS

Brazilin actuated ferroptosis in breast cancer cells, and the underlying mechanism is mainly associated with the p53/SLC7A11/GPX4 signaling pathway.

Article review: Brazilin as potential anticancer agent

Brazilin is the main compound in Caesalpinia sappan and Haematoxylum braziletto, which is identified as a homoisoflavonoid based on its molecular structure. These plants are traditionally used as an anti-inflammatory to treat fever, hemorrhage, rheumatism, skin problems, diabetes, and cardiovascular diseases. Recently, brazilin has increased its interest in cancer studies. Several findings have shown that brazilin has cytotoxic effects on colorectal cancer, breast cancer, lung cancer, multiple myeloma, osteosarcoma, cervical cancer, bladder carcinoma, also other cancers, along with numerous facts about its possible mechanisms that will be discussed. Besides its flavonoid content, brazilin is able to chelate metal ions. A study has proved that brazilin could be used as an antituberculosis agent based on its ability to chelate iron. This possible iron-chelating of brazilin and all the studies discussed in this review will lead us to the statement that, in the future, brazilin has the potency to be a chemo-preventive and anticancer agent. The article review aimed to determine the brazilin mechanism and pathogenesis of cancer.

Effects of Encapsulation of Caesalpinia sappan L. with Cyclodextrins for Bovine Mastitis

The main components of Caesalpinia sappan L. (CS) are brazilin and brazilein, which show high potential in pharmacologic applications. However, these have been drastically limited by the poor water solubility and stability. The present study investigates the formation of inclusion complexes F1, F2, and F3 between CS and β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD), and methyl-β-cyclodextrin (MβCD), respectively. These complexes were characterized by Fourier transform infrared spectroscopy (FT-IR). The results showed that the highest encapsulation efficiency and loading capacity of CS extract were 44.24% and 9.67%, respectively. The solubility and stability of CS extract were significantly increased through complexation in phase solubility and stability studies. The complexes F1-F3 showed mainly significant antibacterial activities on gram-positive bacteria pathogens causing mastitis. Moreover, the expression levels of COX-2 and iNOS were significantly decreased in LPS-induced inflammatory cells at concentrations of 50 and 100 µg/mL. In addition, treatment of complex F3 (CS/MβCD) in bovine endothelial cells remarkably increased the chemokine gene expression of CXCL3 and CXCL8, which were responsible for immune cell recruitment (9.92 to 11.17 and 8.23 to 9.51-fold relative to that of the LPS-treated group, respectively). This study provides a complete characterization of inclusion complexes between CS extract and βCD, HPβCD, and MβCD for the first time, highlighting the impact of complex formation on the pharmacologic activities of bovine mastitis.

Brazilin inhibits bladder cancer by promoting cell necroptosis

Brazilin possesses anticancer effects, but the mechanisms are poorly understood. This study investigated the mechanisms of brazilin-induced cell death in the T24 human bladder cancer cell line. Low serum cell culture and the lactate dehydrogenase assay were used to confirm the antitumor effect of brazilin. Annexin V and propidium iodide double staining, transmission electron microscopy, fluo-3-AM assay for Ca²⁺ mobilization and caspase activity assay were performed to identify the type of cell death after brazilin treatment. Mitochondria membrane potentials were measured using JC-1. Quantitative real-time polymerase chain reaction and western blot analyses were performed to verify the expression of the necroptosis-related genes and proteins receptor interacting protein 1 (RIP1), RIP3 and mixed lineage kinase domain-like (MLKL). The results showed that brazilin induced necrosis in T24 cells and upregulated the mRNA and protein levels of RIP1, RIP3 and MLKL and Ca²⁺ influx. The necroptosis-mediated cell death was rescued by the necroptosis inhibitor necrostatin-1 (Nec-1), but not by the apoptosis inhibitor z-VAD-fmk. Brazilin repressed caspase 8 expression and decreased the mitochondrial membrane potentials; both effects were partially reversed by Nec-1. Brazilin induced physiological and morphological changes in T24 cells and RIP1/RIP3/MLKL-mediated necroptosis might be involved. In conclusion, the results confirm the involvement of necroptosis in brazilin-induced cell death and suggest that brazilin could be explored as an anticancer agent against bladder cancer.

Brazilin inhibits the invasion and metastasis of breast cancer

This study aimed to determine the effect of brazilin on the invasion and metastasis of breast cancer. The breast cancer MDA-MB-231 and 4T1 cells were treated with brazilin to investigate proliferation and invasion using cell proliferation assay, wound healing assay, transwell assay. BALB/C mice were randomized into normal, model, positive control, and Sappan L. extract groups (n=6/group). The mice were injected with 4T1 cells via caudal veins to establish a lung metastasis model and via subcutaneous injection to establish a xenograft model. Metastatic nodules on the lung surface, survival rates and visceral indices were evaluated. Subcutaneous tumor volumes and weights were measured. Brazilin inhibited the proliferation of breast cancer cells and significantly inhibited the wound healing, migration, and invasion of MDA-MB-231 and 4T1 cells. Compared with the normal group, the average survival days and spleen index in the model group were significantly decreased, but the lung index and number of pulmonary metastatic nodules were significantly increased. Compared with the model group, the average survival and spleen index of dose groups were significantly increased, and the lung index, the number of pulmonary metastatic nodules, and tumor volume and weight were significantly decreased. Brazilin significantly inhibits the proliferation and metastasis of breast cancer. This study might suggest a new therapeutic agent for breast cancer.

Protective role of Caesalpinia sappan extract and its main component brazilin against blue light-induced damage in human fibroblasts

BACKGROUND

Ultraviolet (UV) radiation is a well-known factor that causes skin aging. Recently, with the development of technology, the skin has been exposed to not only the UV radiation but also the blue light from electronic devices. Blue light is a high-energy visible light that penetrates deep into the dermal layer, producing reactive oxygen species (ROS) and resulting in skin aging. In this study, we searched for candidate materials that can inhibit blue light-induced skin aging and found Caesalpinia sappan extract (CSE) to be effective.

METHODS

Human dermal fibroblasts (HDFs) were treated with various concentrations of CSE and brazilin and exposed to blue light. We measured that antioxidant activity, MMP-1 levels using MMP-1 ELISA, changes in collagen type 1, collagen type 3, MMP-1, and MMP-3 mRNA expressions, and ROS generation.

RESULTS

We confirmed that CSE has high absorption of blue light and antioxidant activity. Blue light irradiation at 30 J/cm² decreased the expression of collagen types 1 and 3, increased the expression of matrix metalloproteinase (MMP)-1 and 3, and decreased the production of ROS in human dermal fibroblasts as compared to those of the nonirradiated group. However, pretreatment with CSE protected against the damage caused by the blue light. Brazilin, a major constituent of C. sappan, had high absorbance in the blue light region and antioxidant activities. Pretreatment with brazilin also inhibited the damage caused by the blue light in the cells.

CONCLUSION

CSE and brazilin are potential agents for inhibiting skin aging caused by blue light-induced damage.

Antibacterial Activity against Foodborne Pathogens and Inhibitory Effect on Anti-Inflammatory Mediators' Production of Brazilin-Enriched Extract from Caesalpinia sappan Linn

Caesalpinia sappan L. heartwood was collected from Mae Chaem District, Chiang Mai Province, Thailand. Crude extracts were prepared by Soxhlet’s extraction using 50, 60, and 70% of ethanol (EtOH) at 50, 60, and 70 °C, and the brazilin content was measured using reversed-phase high performance liquid chromatography (RP-HPLC). The antibacterial activity against foodborne pathogens and anti-inflammatory aspects were investigated. C. sappan, prepared from 70% EtOH at 70 °C (E70T70), significantly (p < 0.05) exhibited the highest amount of brazilin (7.90 ± 0.50% w/w). All extracts were investigated for anti-inflammatory activity through an inhibition effect on nitric oxide (NO) and inducible nitric oxide synthase (iNOS) production in RAW264.7 mouse macrophage cells. The inhibitory effect on cyclooxygenase-2 (COX-2) production in HT-29 and HCT116 was also studied. All the extracts inhibited NO, iNOS, and COX-2 production induced by combined lipopolysaccharide and interferon-γ, especially E70T70, indicating the highest inhibition effect among other extracts. Additionally, E70T70 was selected to determine the antibacterial activity against foodborne pathogens, including Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, and Vibrio parahaemolyticus. The result showed that 200 µg/mL extract reduced all test pathogens 100% at 24 h. These results suggested the potential of using C. sappan L. extract as a natural preservative in food and a natural active pharmaceutical ingredient.

Brazilin Isolated from Caesalpina Sappan Wood Induces Intrinsic Apoptosis on A549 Cancer Cell Line by Increasing p53, caspase-9, and caspase-3

Objective:

Lung cancer is the leading cause of death among cancer patients. The majority of lung cancer is the Non-Small Lung Carcinoma (NSLC). This study evaluated the potency of brazilin isolated from Caesalpinia sappan wood to induce apoptosis on non-small lung carcinoma cell line, A549, by examining the expression of p53, caspase-9, and caspase-3.

Methods:

Brazilin was isolated from Caesalpinia sappan wood following a guided assay and it was determined by using Brazilin®SIGMA as standard. The activity of brazilin on the growth of A549 cell line was analysed by MTT assay and the apoptosis was evaluated by flowcytometer following Annexin V (FITC) and PI staining. The expression of p53, caspase-9, and caspase-3 was examined by immunocytochemistry.

Result:

The IC50 of brazilin on A549 cell line was 43µg/mL. Cell treatment with 20 µg/mL and 40 µg/mL of brazilin significantly increased early apoptosis (p<0.001). Cell treatment with 40 µg/mL of Brazilin significantly increased late apoptosis (p<0.001). Brazilin significantly increased the expression of p53, Caspase-9, and caspase-3 (p<0.001).

Conclusion:

This study showed evidence of the activity of brazilin to induce intrinsic apoptosis on a NSLC cell line A549.

Protective Effects of Caesalpinia sappan Linn. and Its Bioactive Compounds on Cardiovascular Organs

Cardiovascular diseases are the leading cause of death worldwide. The long-term aim of cardiovascular disease therapy is to reduce the mortality rate and decelerate the progression of cardiovascular organ damage. Current therapies focus on recovering heart function and reducing risk factors such as hyperglycemia and dyslipidemia. However, oxidative stress and inflammation are important causes of further damage to cardiovascular organs. Caesalpinia sappan Linn. (Fabaceae), a flowering tree native to tropical Asia, has antioxidant and anti-inflammatory properties. It is used as a natural dye to color food and beverages and as a traditional treatment for diarrhea, diabetes, and blood stasis. The phytochemical compounds in C. sappan, mainly the homoisoflavonoids brazilin, sappanone A, protosappanin, and hematoxylin, can potentially be used to protect cardiovascular organs. This review aims to provide updates on recent developments in research on C. sappan in relation to treatment of cardiovascular diseases. Many studies have reported protective effects of the plant’s bioactive compounds that reduce cardiac damage and enhance vasorelaxation. For example, brazilin and sappanone A have an impact on molecular and cellular changes in cardiovascular disease pathogenesis, mainly by modulating oxidative, inflammatory, and apoptotic signaling pathways. Therefore, bioactive compounds of C. sappan have the potential to be developed as therapeutic agents to combat cardiovascular diseases like myocardial infarction and vascular disease. This review could help further the understanding of the possible modulatory role of the compounds in cardiovascular diseases, thereby facilitating future studies.

Phytochemical characterisation and in vivo antilithiatic activity of the stems of Caesalpinia bahamensis (Brasilete)

The aim of this work was to identify the main chemical constituents and to evaluate the antilithiatic activity of the aqueous and hydroalcoholic extracts of stems of Caesalpinia bahamensis Lam. Fractionation and isolation of constituents from the hydroalcoholic extract was carried out by flash chromatography and semi-preparative liquid chromatography. The antilithiatic activity of the aqueous and hydroalcoholic extracts was evaluated in Wistar rats, where kidney stones were induced by ethylene glycol and ammonium chloride. Creatinine, calcium, and oxalate levels were evaluated and histological analysis was carried out. The homoisoflavonoids protosappanin B, 10-methyl-protosappanin B and brazilin were isolated and the antilithiatic activity of the aqueous and hydroalcoholic extracts was demonstrated by the reduction of the concentration of calcium and oxalate in urine compared to the lithiasis group. It was corroborated by histological analysis. Brazilin and protosappanin B were proposed as chemical markers for this plant species.

Integrative Bioinformatics Analysis Reveals Potential Target Genes and TNFα Signaling Inhibition by Brazilin in Metastatic Breast Cancer Cells

OBJECTIVE

Metastasis is the most significant cause of morbidity and mortality in breast cancer patients. Previously, a combination of brazilin and doxorubicin has been shown to inhibit metastasis in HER2-positive breast cancer cells. This present study used an integrative bioinformatics approach to identify new targets and the molecular mechanism of brazilin in inhibiting metastasis in breast cancer.

METHODS

Cytotoxicity and mRNA arrays data were retreived from the DTP website, whereas genes that regulate metastatic breast cancer cells were retreived from PubMed with keywords "breast cancer metastasis". Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and Drug association analysis were carried out by using WEB-based GEne SeT AnaLysis Toolkit (WebGestalt). Construction of protein-protein interaction (PPI) network analysis was performed by STRING-DB v11.0 and Cytoscape, respectively. The genetic alterations of the potential therapeutic target genes of brazilin (PB) were analyzed using cBioPortal.

RESULTS

Analysis of cytotoxicity with the public database of COMPARE showed that brazilin exerts almost the same cytotoxicity in the NCI-60 cells panel showing by similar GI50 value, in which the lowest GI50 value was observed in MDA-MB 231, a metastatic breast cancer cells. KEGG enrichment indicated several pathways regulated by brazilin such as TNF signaling pathway, cellular senescence, and pathways in cancer. We found ten drugs that are associated with PB, including protein kinase inhibitors, TNFα inhibitors, enzyme inhibitors, and anti-inflammatory agents.

CONCLUSION

In conclusion, this study identified eight PB, including MMP14, PTGS2, ADAM17, PTEN, CCL2, PIK3CB, MAP3K8, and CXCL3. In addition, brazilin possibly inhibits metastatic breast cancer through inhibition of TNFα signaling. The study results study need to be validated with in vitro and in vivo studies to strengthen scientific evidence of the use of brazilin in breast cancer metastasis inhibition.

Roles of JNK/Nrf2 Pathway on Hemin-Induced Heme Oxygenase-1 Activation in MCF-7 Human Breast Cancer Cells

Heme oxygenase-1 (HO-1) is highly induced in various human disease states, including cancer, indicating that HO-1 is an emerging target of cancer therapy. In this study, we investigated that the mechanisms of hemin-induced HO-1 expression and its signaling pathways in human breast cancer cell. We used MCF-7 cells, a human breast cancer cell line. Hemin increased HO-1 expression in MCF-7 cells in a dose- and time-dependent manner. Hemin enhanced HO-1 expression through the activation of c-Jun N-terminal kinases (JNK) signaling pathway. Hemin also induced activation of Nrf2, a major transcription factor of HO-1 expression. These responses in MCF-7 cells were completely blocked by pretreatment with brazilin, a HO-1 regulator. These results indicated that brazilin inhibits hemin-induced HO-1 expressions through inactivation of JNK/Nrf2 in MCF-7 cells. Thus, our findings suggest that HO-1 is an important anticancer-target of brazilin in human breast cancer.

Brazilin Treatment Produces Antidepressant- and Anxiolytic-Like Effects in Mice

Increasing evidence shows depression relevant to oxidative stress and inflammation. Anti-inflammatory strategies or antioxidants have led to the development of new antidepressants. Brazilin is a natural product from the Chinese traditional medicine Caesalpinia sappan L., exerting anti-inflammatory, antioxidant, anti-platelet concentration, and anti-cancer effects. While the antidepressant effect of brazilin is largely unknown. In present study, we investigated the effects of brazilin on H₂O₂-induced oxidative injury in PC12 cells and on depression- and anxiety-like behaviors of chronically mild stressed (CMS)-induced depression mice. It was found that brazilin pre-treatment (both 10 and 20 µM) significantly increased cell viability and decreased cell apoptosis in H₂O₂-treated PC12 cells. Furthermore, repetitive administration of brazilin to CMS-induced depression mice by intraperitoneal injection (10 mg/kg) made the mice significantly lose their latency of feeding in novelty-suppressed feeding test (NSF), have more the sucrose preference in sucrose preference test (SPT), and more time spent in the central zone without affecting their crossing activity in open field test (OFT). These results suggested that brazilin can play a role in antidepressant and anxiolytic-like behaviors for CMS-induced depression mice probably through inhibiting the oxidative stress. Therefore, brazilin is worth to be further explored for treating depressive and anxiety disorders.

[Effect of brazilin on apoptosis and autophagy of tongue cancer Tca8113 cells and its molecular mechanism]

OBJECTIVE

To investigate the effects of brazilin on the proliferation, apoptosis and autophagy of human tongue squamous cell carcinoma Tca8113 cells in vitro and explore its molecular mechanism.

METHODS

The changes in the proliferation, morphology and apoptosis of Tca8113 cells in response to brazilin treatment were detected using MTT assay, Hoechst33342 staining, and Annexin V/PI double staining, respectively. The expressions of apoptosis-related protein Bax, Bcl-2, cleaved caspase-3 and autophagy-related proteins p-AMPK, p-mTOR, LC3B, and p62 in the treated cells were detected using Western blotting. The effect of treatment with both the AMPK pathway inhibitor and brazilin on the expressions of the pathway-related proteins p-AMPK, p-mTOR, and LC3B was assessed.

RESULTS

MTT assay showed that brazilin significantly inhibited the proliferation of Tca8113 cells with an IC50 of 31.17 μmol/L at 24 h. Hoechst33342 staining showed that brazilin induced apoptotic morphological changes in Tca8113 cells in a concentration-dependent manner. Treatment with different concentrations of brazilin resulted in increased apoptosis in the cells. Brazilin obviously inhibited the expression of Bcl-2, p62 and p-mTOR and enhanced the expressions of Bax, cleaved caspase-3, LC3B and p-AMPK. The AMPK pathway inhibitor significantly inhibited the increase in p-AMPK and LC3B expressions and the decrease in p-mTOR expression induced by brazilin.

CONCLUSIONS

Brazilin can inhibit the proliferation and promote apoptosis in Tca8113 cells and at the same time induces autophagy in the cells through the AMPK/mTOR pathway.

Caesalpinia sappan: A promising natural source of antimicrobial agent for inhibition of cariogenic bacteria

From the previous findings, the ethanolic fractionated extract of Caesalpinia sappan (F-EtOH) has high activity against Streptococcus mutans, the most severe cariogenic bacteria. The present study was aimed to isolate and identify the active compound of F-EtOH and compare its inhibitory activity against the biofilm of S. mutans as well as the cytotoxicity to oral fibroblast cells with F-EtOH. Compound isolation was done by column chromatography. The active compound was identified using liquid chromatography-mass spectrometry with electrospray ionization and nuclear magnetic resonance spectroscopy. It was found that the major compound of F-EtOH is brazilin. F-EtOH and brazilin were compared for inhibitory potential on the biofilms of three strains of S. mutans. The results exhibited that both F-EtOH and brazilin had potential on inhibiting biofilm formation and eradicating the preformed biofilms and their activity was dose dependent. F-EtOH showed significantly less toxic to normal periodontal ligament fibroblast than brazilin. At low concentration of 1- and 2-MBC, F-EtOH showed higher effective than brazilin. The results of our study suggest that the antibacterial activity of F-EtOH is according to the synergistic effects of the existing compounds including brazilin in F-EtOH.

Preliminary study on the effect of brazilin on biofilms of Staphylococcus aureus

Biofilms significantly enhance antibiotic resistance by inhibiting penetration of antibiotics and are shielded from the immune system via the formation of an extracellular polymeric matrix. Innovative and novel approaches are required for the inhibition of biofilm formation and treatment of biofilm-associated infectious diseases. In the current study, a biofilm model of Staphylococcus aureus was established in vitro to explore inhibitory effects of brazilin (BN) on biofilm formation and to evaluate damaging effects of BN in the presence and absence of vancomycin (VCM) on the biofilm. Antibiofilm-infection mechanisms of BN were observed. In these experiments, the clinical strain of S. aureus C-4-4 was isolated for biofilm formation. Crystal violet staining and fluorescence microscopy revealed that BN inhibited biofilm formation in vitro and the best effect was observed with two times the minimum inhibitory concentration of BN following 48 h incubation. Additionally, the results demonstrated that BN in combination with VCM enhanced the damage to biofilms, whereas VCM alone did not. The results of the reverse transcription-quantitative polymerase chain reaction analyses demonstrated that BN downregulated gene expression of intercellular adhesion (ica)A and upregulated icaR and the quorum-sensing (QS) system regulator accessory gene regulator A. In summary, BN inhibited S. aureus biofilm formation and destroyed biofilms, while simultaneously increasing permeability to VCM. BN was able to reduce production of the extracellular polymeric matrix and inhibited the QS system. These results support the use of BN as a novel drug and treatment strategy for S. aureus biofilm-associated infections.

Brazilin Inhibits Prostatic Acidic Phosphatase Fibrillogenesis and Decreases its Cytotoxicity

A 39-amino acid peptide fragment that is derived from prostatic acidic phosphatase (PAP), PAP_248-286 , is secreted in large amounts in human semen and forms amyloid fibrils. These fibrils can capture HIV virions and increase the attachment of virions to target cells; as such, they are called a "semen-derived enhancer of virus infection" (SEVI). Therefore, the inhibition of the formation of PAP_248-286 amyloid fibrils is of great significance. Herein, we demonstrate that brazilin effectively inhibits PAP_248-286 aggregation. The inhibitory effect increases with increasing brazilin concentration. Thioflavin T fluorescence assays and TEM observations confirmed that a few fibrils formed when brazilin was present with PAP_248-286 in an equimolar concentration. Circular dichroism spectroscopy indicated that brazilin inhibited the secondary structural transitions from α-helices and random coils into β-sheets. Cytotoxicity assays showed that brazilin significantly decreased the cytotoxicity of the fibrils at 0.01 mmol L^-1 . Isothermal titration calorimetry revealed that hydrophobic interactions were the main driving force for the binding of brazilin to the PAP_248-286 monomer (dissociation constant, 4.03 μmol L^-1 ), and that the binding affinity of brazilin for the fibrils was at least three orders of magnitude lower than that for the monomer. These results indicate that brazilin holds great potential as a small-molecule agent against SEVIs.

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

We have synthesized a series of cis-6a,7,8,12b-tetrahydro-6H-naphtho[2,1-c]chromen-6a-ols as B-ring-modified analogues of (±)-brazilin. A completely regio- and cis-diastereoselective intramolecular Friedel–Crafts epoxy–arene cyclization of 1-tetralone-derived glycidyl ethers catalyzed by Brønsted acids was used as the key step. Our worries concerning the formation of cis–trans product mixtures and their probable conversion to naphthopyran derivatives via dehydration of the tertiary hydroxy group were laid to rest. Additionally, the angular hydroxy group of one of the synthesized products has been reductively removed by a diastereoselective method which should be useful in future for preparing libraries of chroman-fused tetralins with trans-stereochemistry at the ring junction.

inhibits rheumatoid arthritis activity in a type-II collagen induced arthritis mouse model

BACKGROUND

Caesalpinia sappan L. extracts exhibit great therapeutic potential, and have been shown to have analgesic and anti-inflammatory properties. This study aimed to understand the anti-rheumatoid activity of brazilin that was isolated from ethyl acetate extract of C. sappan L. The evaluations were conducted in mice with type-II collagen-induced arthritis (CIA).

METHODS

Brazilin was purified via preparative HPLC and identified by mass spectrometry and 1H/13C NMR analysis. DBA/1J mice were divided into four groups (n=10). Three groups of mice received intradermal injections of inducer bovine type-II collagen (BTIIC; 2 mg/ml in 0.05 ml acetic acid) and 0.1 ml of booster complete Freund's adjuvant (CFA). A second injection of BTIIC with booster incomplete Freund's adjuvant (ICFA) was given subsequently after 21 days. On 22nd day, purified brazilin (10 mg/kg body weight) or the disease-modifying anti-rheumatic drug methotrexate (3 mg/kg body weight) was administered intraperitoneally daily or every three days for 21 days, respectively to two groups of mice. At the 42nd day, mice sera were collected, and the levels of pro-inflammatory cytokines and stress enzyme markers in serum were measured using standard immunoassay methods. The microstructure and morphometric analyses of the bones were assessed using high-resolution microfocal computed tomography.

RESULTS

Brazilin isolated from C. sappan reduced the arthritis index score and the extent of acute inflammatory paw edema in CIA-mice. The bone mineral density was significantly (p<0.05) lower in only-CIA mice, and appeared to increase commensurate with methotrexate and brazilin administration. Brazilin prevented joint destruction, surface erosion, and enhanced bone formation as revealed by microstructural examinations. Brazilin markedly attenuated mouse CIA and reduced the serum levels of inflammatory cytokines including TNF-α, IL-1β, and IL-6.

CONCLUSIONS

Brazilin purified from C. sappan L. shows protective efficacy in CIA mouse, and may be useful to treat chronic inflammatory disorders including rheumatoid arthritis.

c-Fos is involved in inhibition of human bladder carcinoma T24 cells by brazilin

Crude brazilin extract from Sappan wood has demonstrated strong anti tumor activity in the mouse model of human bladder carcinoma and clinical trial for intravesical therapy. Purified brazilin was confirmed the most active molecule in inhibition of bladder carcinoma T24 cells. Brazilin decreased proliferation and viability of T24 cells in a dose- and time-dependent manner, with a calculated LC50 of 32 µg/mL. More than 1,000 of genes were found upregulated and down regulated by brazilin treatment in digital gene expression profiling. Gene ontology analysis indicated that stress response, apoptosis, and cell cycle regulatory pathways were highly enriched. Among the regulated genes, c-Fos was the most and specifically upregulated. Overexpression of c-Fos in T24 cells resulted in tumor cell specific changes in cell morphology and viability. Over expression of stress-responsive gene, HSP70, and other highly upregulated genes did not have any effect on cell growth. Brazilin may inhibit T24 cell growth and trigger cell death through a c-Fos-mediated and tumor cell specific signaling pathway. Further studies of its down stream mediators may help to identify better tumor cell type specific drug targets.