Dracorhodin Perchlorate Induces A375-S2 Cell Apoptosis via Accumulation of p53 and Activation of Caspases

Cascade Reactions of Alkynyl Ketones and Amides to Generate Unsaturated Oxacycles and Aromatic Carbocycles

We describe novel amine-mediated transformation of alkynyl ketones and amides to generate 2-methylene-2H-pyrans, substituted 3-hydroxy-9H-fluoren-9-ones, and amine-incorporated arenes. These cascade processes are initiated by conjugate addition of secondary amine followed by hydrolysis of the enamine/vinylogous amide intermediates. The product distribution is highly sensitive to the steric and electronic effects of the substituents on both the alkyne moieties, the tether structure connecting them, and the nature of the amine. Alkynyl amide participates in the Alder-ene reaction favorably to generate more reactive allene amide that reacts with amine to generate amine-incorporated arene products. These metal-free cascade reactions are a useful synthetic method that can be exploited for the construction of various hetero- and carbocyclic systems.

Cyclization Reactions of In Situ-Generated Acyl Ketene with Ynones to Form Oxacycles

Acyl ketenes react with polar unsaturated functional groups to give unique heterocyclic rings, yet reactions with unpolarized unsaturated functional groups have not been reported. Herein, we describe two effective ring-forming reactions between acetyl ketene and electron-deficient alkynes. The first reaction involves in situ tethering between acetyl ketene and nucleophile-containing 1,3-diynones, which promotes sequential intramolecular 1,6/1,4-additions to generate 2-methylene-2H-pyrans in various yields (24-91%). The other involves a zwitterionic intermediate generated from acetyl ketene and DABCO, which undergoes a Michael addition with terminal alkynyl ketones to generate 3-acyl-4-pyrones (11-79%).

Polyacylated Anthocyanins Derived from Red Radishes Protect Vascular Endothelial Cells Against Palmitic Acid-Induced Apoptosis via the p38 MAPK Pathway

Palmitic acid (PA), a widely consumed saturated fat, is known to induce the apoptosis of vascular endothelial cells. This study examined the protective effect of anthocyanin from red radish (ARR), which has been shown to protect the cardiovascular system and is rich in polyacylated pelargonidin (P) glycosides, on PA-treated SV 40 transfected aortic rat endothelial cells (SVAREC). In all, 22 distinct anthocyanins were identified in the ARR via ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry, the most abundant of which were pelargonidin-3-(p-coumaroyl)diglucoside-5-glucoside (31.60%), pelargonidin-3-(feruloyl)diglucoside-5-(malonyl)glucoside (22.98%), pelargonidin-3-(p-coumaroyl)diglucoside-5-(malonyl)glucoside (8.02%), and pelargonidin-3-(feruloyl)diglucoside-5-glucoside (6.25%). P displayed the highest serum level (93.72%) in the ARR-treated mice, while polyacylated P glucosides were also absorbed intact. Furthermore, ARR treatment effectively increased cellular activity and reduced the ratio of Bcl-2-associated X protein : B cell lymphoma-2, while simultaneously alleviating the excessive production of reactive oxygen species in PA-treated SVAREC. Transcriptome and further verification analyses confirmed that the ARR-inhibiting PA-induced apoptosis of SVAREC was related to the p38 mitogen-activated protein kinase signaling pathway. Our results are the first to demonstrate that ARR may be a promising phytochemical in the prevention of PA-induced endothelial dysfunction.

Daemonorops draco Blume Induces Apoptosis Against Acute Myeloid Leukemia Cells via Regulation of the miR-216b/c-Jun

Daemonorops draco Blume (DD), also called dragon’s blood, has been used as a traditional Korean medicine, especially for relieving pain caused by wound infection. Recently, it has been described that DD has antibacterial and analgesic effects. In this study, the underlying anticancer effect of DD associated with apoptosis was investigated in acute myeloid leukemia cell lines U937 and THP-1. DD exhibited cytotoxic effects and induced apoptosis in U937 and THP-1 cells. Moreover, DD treatment significantly reduced mitochondrial membrane potential (ΔΨ). The protein expression of cleaved poly(ADP-ribose) polymerase, cleaved caspase-3, p-H2A.X, CCAAT/enhancer-binding protein (CHOP), and activating transcription factor 4 was upregulated by DD treatment. Consistently, DD-treated cells had increased reactive oxygen species (ROS) level in a concentration-dependent manner via miR-216b activation in association with c-Jun inhibition. N-acetyl-L-cysteine pretreatment reversed the cytotoxic effect of DD treatment as well as prevented ROS accumulation. Collectively, the results of this study suggest that the anticancer effect of DD in AML was mediated by CHOP-dependent apoptosis along with ROS accumulation and included upregulation of miR-216b followed by a decrease in c-Jun.

Dracorhodin perchlorate enhances wound healing via β-catenin, ERK/p38, and AKT signaling in human HaCaT keratinocytes

Dracorhodin can be isolated from the exudates of the fruit of Daemonorops draco. Previous studies suggested that dracorhodin perchlorate can promote fibroblast proliferation and enhance angiogenesis during wound healing. In the present study, the potential bioactivity of dracorhodin perchlorate in human HaCaT keratinocytes, were investigated in vitro, with specific focus on HaCaT wound healing. The results of in vitro scratch assay demonstrated the progressive closure of the wound after treatment with dracorhodin perchlorate in a time-dependent manner. An MTT assay and propidium iodide exclusion detected using flow cytometry were used to detect cell viability of HaCaT cells. Potential signaling pathways underlying the effects mediated by dracorhodin perchlorate in HaCaT cells were clarified by western blot analysis and kinase activity assays. Dracorhodin perchlorate significantly increased the protein expression levels of β-catenin and activation of AKT, ERK and p38 in HaCaT cells. In addition, dracorhodin perchlorate did not induce HaCaT cell proliferation but promoted cell migration. Other mechanisms may yet be involved in the dracorhodin perchlorate-induced wound healing process of human keratinocytes. In summary, dracorhodin perchlorate may serve to be a potential molecularly-targeted phytochemical that can improve skin wound healing.

Dracorhodin perchlorate induces apoptosis and G2/M cell cycle arrest in human esophageal squamous cell carcinoma through inhibition of the JAK2/STAT3 and AKT/FOXO3a pathways

Dracorhodin perchlorate (DP), a synthetic analogue of the anthocyanin red pigment dracorhodin, has been shown to exert various pharmacological effects, including anticancer activity. However, its effects on human esophageal squamous cell carcinoma (ESCC) cells have not been previously investigated, and the molecular mechanisms underlying its anticancer activity remain unclear. In the present study, it was demonstrated that DP significantly reduced the viability of ESCC cells compared with that noted in normal human liver LO2 cells. Treatment with DP induced G2/M phase cell cycle arrest through upregulation of p21 and p27, and downregulation of cyclin B1 and Cdc2. Furthermore, DP treatment induced caspase-dependent apoptosis, which could be reversed by exposure to Z-VAD-FMK, a caspase inhibitor. Western blotting demonstrated that DP induced apoptosis through extrinsic and intrinsic pathways by upregulating death receptor 4 (DR4), DR5, cleaved caspase-3/-7/-9 and cleaved poly (ADP-ribose) polymerase (PARP), and by decreasing total PARP, total caspase-3/7, Bcl-2 and caspase-9/-10. Moreover, DP treatment decreased the phosphorylation of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), AKT, and forkhead box O3a (FOXO3a) in ESCC cells, indicating that the activity of the JAK2/STAT3 and AKT/FOXO3a signaling pathways was inhibited. Therefore, DP is a promising therapeutic agent for ESCC.

Anti-inflammatory Flavan-3-ol-dihydroretrochalcones from Daemonorops draco

Four A-type flavan-3-ol-dihydroretrochalcone dimers, dragonins A-D (1-4), were characterized from the traditional Chinese medicine Sanguis Draconis. The structures of 1-4 were elucidated by spectroscopic and spectrometric analyses. Compounds 1 and 2 exhibited significant inhibition of fMLP/CB-induced superoxide anion and elastase. The signaling pathways accounting for the inhibitory effects of compound 2 were also elucidated. These purified A-type flavan-3-ol-dihydroretrochalcones are new potential leads for the development of anti-inflammatory drugs.

Dracorhodin perchlorate induces the apoptosis of glioma cells

Dracorhodin perchlorate (Dp), a synthetic analogue of the antimicrobial anthocyanin red pigment, has recently been shown to induce apoptotic cell death in various types of cancer cells. Yet, the inhibitory effect of Dp on human glioma cells remains uninvestigated. Therefore, in the present study, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were used to detect cell viability and cell cycle progression in glioma U87MG and T98G cells, respectively. Annexin V-FITC/propidium iodide double staining and JC-1 staining were separately applied to determine cellular apoptosis and mitochondrial membrane potential damage in the cells. The expression levels of associated proteins involved in cell cycle progression and apoptosis were measured by western blotting. The activities of caspase‑9/-3 were determined by Caspase-Glo-9/3 assay. The results indicated that Dp treatment significantly inhibited cell proliferation in a dose- and time-dependent manner, and blocked cell cycle progression at the G1/S phase in the U87MG and T98G cells via the upregulation of p53 and p21 protein expression, and simultaneous downregulation of Cdc25A, Cdc2 and P-Cdc2 protein expression. Additionally, Dp treatment led to the loss of cellular mitochondrial membrane potential, and the release of cytochrome c, and strongly induced the occurence of apoptosis. Increased expression levels of Bim and Bax protein and the downregulated expression of Bcl-2 protein were observed. Caspase-9/-3 were activated and their activities were elevated after Dp treatment. These findings indicate that Dp inhibits cell proliferation, induces cell cycle arrest and apoptosis in glioma cells, and is a possible candidate for glioma treatment.

Dracorhodin perchlorate induces G1/G0 phase arrest and mitochondria-mediated apoptosis in SK-MES-1 human lung squamous carcinoma cells

Dracorhodin perchlorate (DP) has recently been revealed to induce apoptosis in various types of cancer. However, the antitumor potential and molecular mechanisms of DP in human lung cancer have not been previously reported. Therefore, the present study aimed to investigate the effects of DP on cell viability, the cell cycle and apoptosis, using an MTT assay, flow cytometry and western blot studies. DP was identified to induce cellular and DNA morphological changes, and decreased the viability of SK-MES-1 human lung squamous carcinoma cells. DP significantly inhibited the growth of SK-MES-1 cells by inducing apoptosis and G₁/G₀ cell cycle arrest in a dose-dependent manner via activation of p53 (P<0.05). Furthermore, DP promoted the significant upregulation of B cell lymphoma-2 (Bcl-2)-activated X protein and significant downregulation of Bcl-2 (P<0.05), inducing dissipation of the mitochondrial membrane potential (MMP). In addition, caspase-3 was activated by DP via the cleavage of its substrate, proteolytic cleavage of poly(ADP-ribose) polymerase. DP also induced caspase-independent apoptosis by significantly increasing the protein expression of the apoptosis-inducing factor (P<0.05), which is localized in mitochondria under the physiological conditions and released into the cytoplasm when MMP is dissipated. Furthermore, the present study demonstrated that DP significantly increased the generation of reactive oxygen species (P<0.05). In conclusion, the current study revealed that DP is able to induce cell cycle arrest and apoptosis in SK-MES-1 cells via activation of the mitochondrial pathway, indicating that DP may be a potential leading compound for the development of future lung cancer therapeutic regimes.

Plumbagin induces the apoptosis of human tongue carcinoma cells through the mitochondria-mediated pathway

BACKGROUND

Plumbagin, a quinonoid constituent isolated from the root of Plumbago zeylanica L., has been proven to possess anti-tumor activity both in vitro and in vivo. However, its anti-tumor properties for human tongue carcinoma have not been reported. This study aimed to investigate the inhibitory effect and the underlying mechanism of plumbagin on the growth of human tongue carcinoma cells.

MATERIAL AND METHODS

Cell proliferation ability was detected by EdU incorporation assay and colony formation assay. Cell-cycle distribution was determined by flow cytometric analysis using propidium iodide (PI) staining. Cellular apoptosis was then evaluated by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Western blotting was applied to assay the expression of Bax and Bcl-2.

RESULTS

Plumbagin inhibited the growth and proliferation of Tca8113 cells in vitro in a concentration- and time-dependent manner. The cell cycles of plumbagin-treated Tca8113 cells were arrested at the G2/M phase. Cells treated with plumbagin presented the characteristic morphological changes of apoptosis. The ratio of Bax/Bcl-2 was raised by plumbagin in a concentration-dependent manner.

CONCLUSIONS

These results indicate that plumbagin induces the apoptosis of Tca8113 cells through mitochondria-mediated pathway.

Dracorhodin perchlorate induced human breast cancer MCF-7 apoptosis through mitochondrial pathways

OBJECTIVE

Dracorhodin perchlorate (DP) was a synthetic analogue of the antimicrobial anthocyanin red pigment dracorhodin. It was reported that DP could induce apoptosis in human prostate cancer, human gastric tumor cells and human melanoma, but the cytotoxic effect of DP on human breast cancer was not investigated. This study would investigate whether DP was a candidate chemical of anti-human breast cancer.

METHODS

The MTT assay reflected the number of viable cells through measuring the activity of cellular enzymes. Phase contrast microscopy visualized cell morphology. Fluorescence microscopy detected nuclear fragmentation after Hoechst 33258 staining. Flowcytometric analysis of Annexin V-PI staining and Rodamine 123 staining was used to detect cell apoptosis and mitochondrial membrane potential (MMP). Real time PCR detected mRNA level. Western blot examined protein expression.

RESULTS

DP dose and time-dependently inhibited the growth of MCF-7 cells. DP inhibited MCF-7 cell growth through apoptosis. DP regulated the expression of Bcl-2 and Bax, which were mitochondrial pathway proteins, to decrease MMP, and DP promoted the transcription of Bax and inhibited Bcl-2. Apoptosis-inducing factor (AIF) and cytochrome c which localized in mitochondrial in physiological condition were released into cytoplasm when MMP was decreased. DP activated caspase-9, which was the downstream of mitochondrial pathway. Therefore DP decreased MMP to release AIF and cytochrome c into cytoplasm, further activating caspase 9, lastly led to apoptosis.

CONCLUSION

Therefore DP was a candidate for anti-breast cancer, DP induced apoptosis of MCF-7 through mitochondrial pathway.

Dracorhodin perchlorate suppresses proliferation and induces apoptosis in human prostate cancer cell line PC-3

The growth inhibition and pro-apoptosis effects of dracorhodin perchlorate on human prostate cancer PC-3 cell line were examined. After administration of 10-80 μmol/L dracorhodin perchlorate for 12-48 h, cell viability of PC-3 cells was measured by MTT colorimetry. Cell proliferation ability was detected by colony formation assay. Cellular apoptosis was inspected by acridine orange-ethidium bromide fluorescent staining, Hoechst 33258 fluorescent staining, and flow cytometry (FCM) with annexin V-FITC/propidium iodide dual staining. The results showed that dracorhodin perchlorate inhibited the growth of PC-3 in a dose- and time-dependent manner. IC50 of dracorhodin perchlorate on PC-3 cells at 24 h was 40.18 μmol/L. Cell clone formation rate was decreased by 86% after treatment with 20 μmol/L of dracorhodin perchlorate. Some cells presented the characteristic apoptotic changes. The cellular apoptotic rates induced by 10-40 μmol/L dracorhodin perchlorate for 24 h were 8.43% to 47.71% respectively. It was concluded that dracorhodin perchlorate significantly inhibited the growth of PC-3 cells by suppressing proliferation and inducing apoptosis of the cells.

Icariin inhibits hydrogen peroxide-induced toxicity through inhibition of phosphorylation of JNK/p38 MAPK and p53 activity

Oxidative stress caused by hydrogen peroxide (H(2)O(2)) plays an important role in the pathogenesis of Alzheimer's disease (AD). The prominent damages caused by H(2)O(2) include the ruin of membrane integrity, loss of intracellular neuronal glutathione (GSH), oxidative damage to DNA as well as the subsequent caspase-3 and p53 activation. Icariin is a flavonoid extracted from the traditional Chinese herb Epimedium brevicornum Maxim. We have previously reported that icariin has a good curative effect on patients with mild cognitive impairment (MCI), AD animal and cell models. However, the molecular mechanism of how icariin exerts neuroprotective effects is still not well understood. To address this question, we exposed undifferentiated neuronal cell lines (PC12 cells) to hydrogen peroxide (H(2)O(2)) and investigated the possible neuroprotective mechanisms of icariin. Vitamin E was used as a positive control. We observed that H(2)O(2) activated the JNK/p38 mitogen-activated protein kinase (MAPK) and induced PC12 cells apoptosis in a concentration-dependent manner. More over, we demonstrated that icariin protected PC12 cells by attenuating LDH leakage, reducing GSH depletion, preventing DNA oxidation damage and inhibiting subsequent activation of caspase-3 and p53, which are the main targets of H(2)O(2)-induced cell damage. In addition, we also found that icariin's neuroprotective effect may partly correlate with its inhibitory effect on JNK/p38 MAPK pathways. Therefore, our findings suggest that icariin is a candidate for a novel neuroprotective drug to against oxidative-stress induced neurodegeneration.

Single-step purification of dracorhodin from dragon's blood resin of Daemonorops draco using high-speed counter-current chromatography combined with pH modulation

Dracorhodin is a major constituent found in "Dragon's blood" resin of Daemonorops draco Willd. Blume. This natural flavylium compound is a potent pharmaceutical substance due to its biological and pharmacological activities such as antimicrobial, antiviral, antitumor and cytotoxic activity. An effective high-speed counter-current chromatography method was successfully established for the isolation and purification of dracorhodin directly from extract of D. draco by using a two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water (2:3:2:3 v/v). Under the optimal conditions, 6.6 mg dracorhodin was obtained from 100 mg crude resin. The isolated fraction of counter-current chromatography was determined by HPLC, NMR, UV/visible and ESI/MS combined with pH modulation, since dracorhodin is unstable in solution which exists in different forms depending on pH values. The data were compared with those of the reference substance, and the literatures as well. The purity of dracorhodin was over 98% based on the HPLC result.

Clematis montana lectin, a novel mannose-binding lectin from traditional Chinese medicine with antiviral and apoptosis-inducing activities

A novel mannose-binding lectin (designated CML) was isolated from Clematis montana Buch.-Ham stem (Ranunculaceae) using ion exchange and gel filtration chromatographies on DEAE-Sepharose and Sephacryl S-100. The purified C. montana lectin was a homodimer of 11,968.9 Da subunits as determined by gel filtration and MS. The hemagglutinating activity of CML was inhibited by branched oligomannosides. The N-terminal 15-amino acid sequence of CML, DNVKYSGQVKNTGSA, has not been reported for other lectins. Also, the peptide mass fingerprinting assay confirmed that there is no match result of similar plant lectins for CML, indicating CML may be a novel plant lectin. CML showed marked antiviral activity against various viruses in cell culture. Subsequently, CML was also found to exhibit remarkable inhibitory effect on L929, HeLa, MCF7 and HepG2 cells. Furthermore, CML specially induced L929 cell apoptosis in dose-dependent manner as evidenced by MTT, fluorescent microscopy, LDH activity-based cytotoxicity assays and DNA ladder. Moreover, due to both caspase inhibitors and Western blot analyses, caspase was also found to play the important role in the potential apoptotic mechanism of CML. When the carbohydrate-binding site was fully inhibited by sugars, cytotoxicity was abruptly decreased and apoptotic phenomenon in L929 cells was not observed, suggesting a significant correlation between mannose-binding-specific activity and the antineoplastic mechanism.

Dragon's blood: botany, chemistry and therapeutic uses

Dragon's blood is one of the renowned traditional medicines used in different cultures of world. It has got several therapeutic uses: haemostatic, antidiarrhetic, antiulcer, antimicrobial, antiviral, wound healing, antitumor, anti-inflammatory, antioxidant, etc. Besides these medicinal applications, it is used as a coloring material, varnish and also has got applications in folk magic. These red saps and resins are derived from a number of disparate taxa. Despite its wide uses, little research has been done to know about its true source, quality control and clinical applications. In this review, we have tried to overview different sources of Dragon's blood, its source wise chemical constituents and therapeutic uses. As well as, a little attempt has been done to review the techniques used for its quality control and safety.

Distinctive role of the cKit receptor tyrosine kinase signaling in mammalian melanocytes

The cKit receptor plays a critical role in melanocyte physiology, influencing melanogenesis, proliferation, migration, and survival of the pigment-producing cells. However, pathways of cKit-mediated intracellular signaling and molecular mechanisms, which regulate specific cellular responses to the activation of the receptor in melanocytes, remain incompletely understood. Here, by using the genetically altered mouse melanocytes expressing an endogenous, constitutively active mutant (D814Y) cKit receptor, we investigated physiological cellular responses to the ligand-independent activation of the receptor tyrosine kinase. It was anticipated that such activation would either trigger uncontrolled proliferation of the melanocytes or stimulate melanin biosynthesis. In contrast to the expectation, we found that constitutive signaling from the cKit receptor did not stimulate melanogenesis and proliferation, but significantly promoted migration of the melanocytes both in vitro and in vivo. We also showed that such signaling is not associated with tumorigenic transformation of the pigment-producing cells. Taken together, our observations suggest that, in mammalian melanocytes, activation of the cKit receptor tyrosine kinase is primarily responsible for transmission of pro-migration signals, which may antagonize proliferation and melanogenesis. Our data also provide an additional explanation as to why malignant melanocytes lose cKit expression during melanoma progression.