Auswahl der wissenschaftlichen Literatur zum Thema „Cucurbitacin D“

Cucurbitacins are triterpenoids commonly found in Cucurbitaceae and Cruciferae and have long been used in traditional medicine. Cucurbitacins demonstrate anti-inflammatory and anti-cancer activities. We investigated whether cucurbitacin D affects viability in breast cancer cells and its mechanism of action. An MTT assay was used to measure the viability of breast cancer cells. Western blot analysis was used to measure the expression of various modulators, such as p-p53, p-Stat3, p-Akt, and p-NF-κB. Doxorubicin and cucurbitacin D affected the viability of MCF7, MDA-MB-231, and SKBR3 cells. Cucurbitacin D and doxorubicin increased p-p53 expression in MCF7, SKBR3, and MDA-MB-231 cells. Cucurbitacin D suppressed p-Akt, p-NF-κB, and p-Stat3 expression in MCF7, MDA-MB-231, and SKBR3 cells. Doxorubicin alone did not decrease p-Akt and p-Stat3 levels. Cucurbitacin D decreased p-NF-κB and p-Stat3 levels. Doxorubicin in combination with cucurbitacin D increased p-p53 levels and suppressed Akt, NF-κB, Stat3, and Bcl-2 expression more than cucurbitacin D alone. Our results clearly demonstrate that cucurbitacin D could be a useful compound for treating human breast cancer.

The objective of this study was to develop a rapid, economic, and efficient method for simultaneous selective isolation, separation, and purification of cucurbitacin D and I from Ecballium elaterium (L.) A. Rich fruit juice via reversed-phase flash chromatography combined with HPLC. The chloroform extract of the fruit juice was fractionated with flash chromatography using a chloroform, acetone and methanol solvent combination at a 5 ml/min flow rate. Then, a validated HPLC method was utilized for purification of the two targeted cucurbitacins. Cucurbitacin D and I were collected automatically by the fraction collector. The fractions containing the same compounds were pooled and lyophilized. The purified cucurbitacin D and I compounds were identified by NMR, LC-MS, and UV spectra analysis. The results suggest that the applied procedure is simple, quick, and highly efficient. The HPLC method was found to be linear, accurate, precise and rugged for the quantification of the cucurbitacins studied.

Phytochemical investigation of the ethyl acetate extract of the stem of Dendrosicyos socotrana Balf. f. resulted in the isolation of a new pentacyclic cucurbitane glycoside Socotroside, in addition to the three known cucurbitacins, dihydrocucurbitacin D, dihydrocucurbitacin F and cucurbitacin G. The structures of the isolated compounds were established on the basis of their spectral data. The isolated cucurbitacin aglycones showed marked cytotoxic activity.

Cucurbitacins are highly oxidized tetracyclic triterpenoids that are widely present in traditional Chinese medicines (Cucurbitaceae family), possess strong anticancer activity, and are divided into 12 classes from A to T with over 200 derivatives. The eight most active cucurbitacin components against cancer are cucurbitacin B, D, E, I, IIa, L glucoside, Q, and R. Their mechanisms of action include antiproliferation, inhibition of migration and invasion, proapoptosis, and cell cycle arrest promotion. Cucurbitacins are also found to be the inhibitors of JAK-STAT3, Wnt, PI3K/Akt, and MAPK signaling pathways, which play important roles in the apoptosis and survival of cancer cells. Recently, new studies have discovered synergistic anticancer effects by using cucurbitacins together with clinically approved chemotherapeutic drugs, such as docetaxel and methotrexate. This paper provides a summary of recent research progress on the anticancer property of cucurbitacins and the various intracellular signaling pathways involved in the regulation of cancer cell proliferation, death, invasion, and migration. Therefore, cucurbitacins are a class of promising anticancer drugs to be used alone or be intergraded in current chemotherapies and radiotherapies to treat many types of cancers.

Abstract A novel cucurbitacin glycoside has been isolated from aerial parts of Kageneckia oblonga R. et P. and shown to be 3β-(β-D-glucosyloxy)-16α,23α-epoxycucurbita-5,24-dien-11-one. The structure was established by usual spectroscopic and two-dimensional (2D ) NMR techniques. This compound has found to be nontoxic when tested in-vivo cell culture assays. In previous investigations we reported 23,24-dihydrocucurbitacin F and prunasine. This was the first report on cucurbitacins from the genus Kageneckia (Rosaceae).

Cucurbitacins, a group of diverse tetracyclic triterpenes, display a variety of biological effects. Glycosylation mediated by glycosyltransferases (UGTs) plays a vital role in structural and functional diversity of natural products and influences their biological activities. In this study, GT-SM, a mutant of UGT74AC1 from Siraitia grosvenorii, was chosen as a potential catalyst in glycosylation of cucurbitacins, and its optimal pH, temperature, and divalent metal ions were detected. This enzyme showed high activity (kcat/Km, 120 s−1 µM−1) toward cucurbitacin F 25-O-acetate (CA-F25) and only produced CA-F25 2-O-β-d-glucose which was isolated and confirmed by 1D and 2D nuclear magnetic resonance. A pathway for uridine diphosphate glucose (UDP-Glc) regeneration and cucurbitacin glycoside synthesis was constructed by combing GT-SM and sucrose synthase to cut down the costly UDP-Glc. The molar conversion of CA-F25 was 80.4% in cascade reaction. Molecular docking and dynamics simulations showed that CA-F25 was stabilized by hydrophobic interactions, and the C2-OH of CA-F25 showed more favorable catalytic conformation than that of C3-OH, explaining the high regioselectivity toward the C2-OH rather than the ortho-C3-OH of CA-F25. This work proved the important potential application of UGT74AC1 in cucurbitacins and provided an understanding of glycosylation of cucurbitacins.

The probable antipyretic, antiinflammatory, analgesic and antioxidant properties of Kageneckia oblonga, Rosaceae, were investigated and the major compounds of its active extracts were isolated. The study comprised the acute toxicity of the extracts of global methanol, hexane, dichloromethane and methanol. The cytotoxicity of global methanol extract was studied in three tumoral cell lines. All the extracts exhibited the pharmacological activities under study. Methanol and dichloromethane were the most toxic extracts. From the global methanol extract, isolations were performed of prunasin, 23,24- dihydro-cucurbitacin F, and a new cucurbitacin, 3β-(β-d-glucosyloxy)-16α,23α-epoxycucurbita-5,24-diene-11-one. The cytotoxicity of both cucurbitacins on human neutrophils at the assayed concentrations was not statistically significant. In-vitro assays showed that both cucurbitacins can be partly responsible for the analgesic, antipyretic, and anti-inflammatory activities. Evaluation was done of the cytotoxicity of global methanol extract, 23, 24-dihydrocucurbitacin F, aqueous extracts and prunasin against P-388 murine leukaemia, A-549 human lung carcinoma and HT-29 colon carcinoma. Since global methanol extract presented a strong cytotoxicity against P-388 murine leukaemia, A-549 human lung carcinoma, and HT-29 cell lines, it is highly probable that this extract contain one or more cytotoxic compounds that could be investigated for their potential use as an agent against cancer.

Two triterpenoids, cucurbitacins B and D, have been isolated from seeds of Iberis umbellata (Cruciferae) and shown to be responsible for the antagonistic activity of a methanolic extract of this species in preventing the 20-hydroxyecdysone (20E)-induced morphological changes in the Drosophila melanogaster BII permanent cell line. With a 20E concentration of 50 nM, cucurbitacins B and D give 50% responses at 1.5 and 10 μM respectively. Both cucurbitacins are able to displace specifically bound radiolabelled 25-deoxy-20-hydroxyecdysone (ponasterone A) from a cell-free preparation of the BII cells containing ecdysteroid receptors. The Kd values for cucurbitacins B and D (5 and 50 μM respectively) are similar to the concentrations required to antagonize 20E activity with whole cells. Cucurbitacin B (cucB) prevents stimulation by 20E of an ecdysteroid-responsive reporter gene in a transfection assay. CucB also prevents the formation of the Drosophila ecdysteroid receptor/Ultraspiracle/20E complex with the hsp27 ecdysteroid response element as demonstrated by gel-shift assay. This is therefore the first definitive evidence for the existence of antagonists acting at the ecdysteroid receptor. Preliminary structure/activity studies indicate the importance of the Δ23-22-oxo functional grouping in the side chain for antagonistic activity. Hexanorcucurbitacin D, which lacks carbon atoms C-22 to C-27, is found to be a weak agonist rather than an antagonist. Moreover, the side chain analogue 5-methylhex-3-en-2-one possesses weak antagonistic activity.

Prostate cancer (PrCa) metastasis is the major cause of mortality and morbidity among men. Metastatic PrCa cells are typically adopted for aberrant glucose metabolism. Thus, chemophores that reprogram altered glucose metabolic machinery in cancer cells can be useful agent for the repression of PrCa metastasis. Herein, we report that cucurbitacin D (Cuc D) effectively inhibits glucose uptake and lactate production in metastatic PrCa cells via modulating glucose metabolism. This metabolic shift by Cuc D was correlated with decreased expression of GLUT1 by its direct binding as suggested by its proficient molecular docking (binding energy −8.5 kcal/mol). Cuc D treatment also altered the expression of key oncogenic proteins and miR-132 that are known to be involved in glucose metabolism. Cuc D (0.1 to 1 µM) treatment inhibited tumorigenic and metastatic potential of human PrCa cells via inducing apoptosis and cell cycle arrest in G2/M phase. Cuc D treatment also showed inhibition of tumor growth in PrCa xenograft mouse model with concomitant decrease in the expression of GLUT1, PCNA and restoration of miR-132. These results suggest that Cuc D is a novel modulator of glucose metabolism and could be a promising therapeutic modality for the attenuation of PrCa metastasis.

Zhang, Siwei.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 87-98).
Abstracts in English and Chinese.
Chapter 1. --- General introduction --- p.1
Chapter 1.1. --- "Types, structure and function of human hemoglobin" --- p.1
Chapter 1.1.1. --- Structure and functions of human hemoglobin --- p.1
Chapter 1.1.2. --- Types of human hemoglobin --- p.2
Chapter 1.2. --- Regulatory mechanism of human hemoglobin expression --- p.3
Chapter 1.2.1. --- The human a and β locus --- p.3
Chapter 1.2.2. --- Development of globin genes switching concept --- p.4
Chapter 1.2.3. --- Factors that regulate globin gene expression --- p.5
Chapter 1.2.3.1. --- The locus control region (LCR) --- p.5
Chapter 1.2.3.2. --- The cis-regulatory elements --- p.5
Chapter 1.2.3.3. --- The trans-acting factors --- p.6
Chapter 1.3. --- The human hemoglobinopathies --- p.8
Chapter 1.3.1. --- α-thalassemia --- p.8
Chapter 1.3.2. --- β-thalassemia --- p.9
Chapter 1.3.3. --- Sickle cell anemia --- p.10
Chapter 1.4. --- Current approaches towards β-thalassemia treatment --- p.11
Chapter 1.4.1. --- Blood transfusion --- p.11
Chapter 1.4.2. --- Bone marrow transplantation --- p.12
Chapter 1.4.3. --- Drug-induced activation of fetal hemoglobin production --- p.12
Chapter 1.4.3.1. --- Hydroxyurea --- p.12
Chapter 1.4.3.2. --- Butyrate and short-chain fatty acids --- p.13
Chapter 1.4.3.3. --- "Mutagens, DNA methyltransferase inhibitors and other HbF inducible agents" --- p.13
Chapter 1.4.3.4. --- Cucurbitacin D --- p.14
Chapter 1.4.4. --- Gene therapy --- p.14
Chapter 1.5. --- Research Objectives --- p.15
Chapter 2. --- "Analysis of CuD, Hydroxyurea and other inducers on the induction of α, β, γ, δ， ε，ζ BP-1 genes and fetal hemoglobin induction" --- p.16
Chapter 2.1. --- Introduction --- p.16
Chapter 2.1.1. --- Properties of human K562 cell line --- p.16
Chapter 2.1.2. --- Induction and measurement of fetal hemoglobin --- p.16
Chapter 2.1.3. --- "Induction of α, β, γ, δ, ε , ζ and BP-1 gene and Real-time RT-PCR analysis" --- p.17
Chapter 2.2. --- Materials --- p.18
Chapter 2.2.1. --- Chemicals and reagents --- p.18
Chapter 2.2.2. --- Kits --- p.19
Chapter 2.2.3. --- Buffers and solutions --- p.19
Chapter 2.2.4. --- Cell lines --- p.20
Chapter 2.3. --- Experimental procedures --- p.20
Chapter 2.3.1. --- Hemoglobin quantity measurement by HbF ELISA --- p.20
Chapter 2.3.1.1. --- MTT assay --- p.21
Chapter 2.3.1.2. --- Preparation of capture-antibody coated ELISA plates --- p.21
Chapter 2.3.1.3. --- Plate blocking --- p.22
Chapter 2.3.1.4. --- Sample and standard preparation --- p.22
Chapter 2.3.1.5. --- HRP antibody and colorimetric detection --- p.23
Chapter 2.3.1.6. --- Statistical analysis --- p.23
Chapter 2.3.2. --- Preparation of mRNA extract from K562 cells --- p.23
Chapter 2.3.3. --- Reverse transcription and Real-time PCR analysis --- p.24
Chapter 2.4. --- Results --- p.25
Chapter 2.4.1. --- CuD significantly upregulates HbF expression in K562 cells --- p.25
Chapter 2.4.2. --- "CuD augments α, β, γ, δ, ε , ζ and BP-1 genes at different level in K562 cells" --- p.28
Chapter 2.4.3. --- Cucurbitacin D-induced γ-globin gene activation requires12-24 hours in K562 cells --- p.31
Chapter 2.5. --- Discussion --- p.33
Chapter 2.5.1. --- Enhancement of fetal hemoglobin production using different chemical compounds --- p.33
Chapter 2.5.2. --- CuD increased HbF synthesis by increasing γ-globin mRNA amount --- p.35
Chapter 2.5.3. --- CuD and HU down-regulated the BP-1 gene expression --- p.36
Chapter 3. --- Determination of potential signal transduction pathways during CuD and HU-mediated fetal hemoglobin production --- p.36
Chapter 3.1. --- Introductions --- p.36
Chapter 3.1.1. --- The p38 MAPK family --- p.37
Chapter 3.1.2. --- The JAK2-STAT3 pathway --- p.38
Chapter 3.1.3. --- Fundamentals on inhibition assay of p38 MAPK and JAK2-STAT3 pathway --- p.39
Chapter 3.1.4. --- Fundamentals on nuclear translocation of STAT3 --- p.41
Chapter 3.2. --- Materials --- p.41
Chapter 3.2.1. --- Chemicals and reagents --- p.41
Chapter 3.2.2. --- Kits --- p.44
Chapter 3.2.3. --- Buffers and solutions --- p.44
Chapter 3.3. --- Experimental procedures --- p.45
Chapter 3.3.1. --- Detection of p3 8 MAPK phosphorylation status --- p.46
Chapter 3.3.1.1. --- Preparation of cytosolic protein extracts --- p.46
Chapter 3.3.1.2. --- Quantitative measurement of phospho-p38 and pan-p38 by ELIS A method --- p.46
Chapter 3.3.1.2.1. --- Antigen adsorption and establishment of standard curves --- p.46
Chapter 3.3.1.2.2. --- Plate washing and application of detection antibody --- p.47
Chapter 3.3.1.2.3. --- Plate washing and application of secondary antibody --- p.47
Chapter 3.3.1.2.4. --- Plate washing and chromogen detection --- p.48
Chapter 3.3.2. --- Detection of signal cascade on JAK2-STAT3 pathway --- p.48
Chapter 3.3.2.1. --- Preparation of cytosolic protein extracts for Western Blot detection --- p.48
Chapter 3.3.2.2. --- Gel running and Western Blot detection --- p.48
Chapter 3.3.3. --- Quantitative measurement of phospho-STAT3-Tyr705 using ELISA method --- p.50
Chapter 3.3.3.1. --- Preparation of cytosolic protein extracts --- p.50
Chapter 3.3.3.2. --- Reconstitution and Dilution of STAT3 [pY705] Standard --- p.50
Chapter 3.3.3.3. --- Measurement of STAT3 [pY705] concentration in cell lysates --- p.51
Chapter 3.3.4. --- Inhibitor assay of JAK2-STAT3 and p38 MAPK pathway --- p.52
Chapter 3.3.4.1. --- Establishment of inhibitor assay --- p.52
Chapter 3.3.4.2. --- HbF ELISA detection --- p.53
Chapter 3.3.5. --- Detection of STAT3 nuclear translocation and DNA binding affinity --- p.53
Chapter 3.3.5.1. --- Preparation of nuclear extract from K562 cells --- p.53
Chapter 3.3.5.2. --- EMS A detection of transcriptional factors binding to γ-promoter region --- p.54
Chapter 3.3.5.2.1. --- 3´ة end-labeling of EMS A probes --- p.54
Chapter 3.3.5.2.2. --- Dot blotting for labeling efficiency estimation --- p.56
Chapter 3.3.5.2.3. --- EMSA binding reaction and non-denaturing gel electrophoresis --- p.57
Chapter 3.3.5.2.4. --- Membrane development and chemiluminescence detection --- p.58
Chapter 3.3.5.3. --- Preparation of K562 samples for immunofluorescence detection --- p.60
Chapter 3.3.5.3.1. --- Slide coating for cell capture --- p.60
Chapter 3.3.5.3.2. --- Preparation of cell slide --- p.60
Chapter 3.3.5.3.3. --- Sample fixation and antibody probing treatment --- p.60
Chapter 3.3.5.3.4. --- Sample imaging and immunofluorescence detection --- p.61
Chapter 3.4 --- Results --- p.62
Chapter 3.4.1. --- Activation of p38 MAPK pathway and STAT3 phosphorylation by hydroxyurea --- p.62
Chapter 3.4.1.1. --- "The p38 MAPK pathway is activated by hydroxyurea, but not activated by Cucurbitacin D" --- p.62
Chapter 3.4.1.2. --- Increased p38 phosphorylation level elicits STAT3 phosphorylation at Ser727 site --- p.64
Chapter 3.4.2. --- Activation of JAK2 and STAT3 phosphorylation by Cucurbitacin D --- p.66
Chapter 3.4.2.1. --- Cucurbitacin D promotes JAK2 activation --- p.66
Chapter 3.4.2.2. --- Cucurbitacin D and hydroxyurea promote STAT3 phosphorylation at Tyr705 site --- p.66
Chapter 3.4.3. --- Basal activity of signal transduction pathways is essential for HbF induction --- p.69
Chapter 3.4.3.1. --- Activation of γ-globin gene requires presence of basal phosphorylation level of p38 MAPK --- p.69
Chapter 3.4.3.2. --- Inhibition on JAK2-STAT3 pathway results in reduced fetal hemoglobin production --- p.71
Chapter 3.4.4. --- Translocation and DNA binding of STAT under Cucurbitacin D induction --- p.72
Chapter 3.4.4.1. --- Cucurbitacin D and hydroxyurea both enhance binding affinity of transcriptional factors to the Gγ/Aγ promoter --- p.72
Chapter 3.4.4.2. --- Cucurbitacin D and hydroxyurea induces nuclear translocation of STAT3 --- p.75
Chapter 3.5. --- Discussion --- p.77
Chapter 3.5.1. --- The role of p38 MAPK activation during γ-globin gene activation --- p.77
Chapter 3.5.2. --- STAT3 phosphorylation at Ser727 site promotes transcription factor activity and γ-globin gene expression --- p.77
Chapter 3.5.3. --- The role of JAK2-STAT3 activation during γ-globin gene activation --- p.78
Chapter 3.5.4. --- Inhibitor assay --- p.79
Chapter 3.5.5. --- Relations between STAT3 nuclear translocation and enhanced fetal hemoglobin production --- p.82
Chapter 4. --- Summery and Prospect --- p.83
Chapter 5. --- References --- p.87

Liu, Kan.
"November, 2010"--Abstract.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (leaves 116-129).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.

Chemotherapy is still the most widely used anti-cancer treatment. The majority of chemotherapeutics inhibit proliferating cells generally, not selectively cancer cells. The side effects associated with chemotherapy can be partly limited by conjugating a cytotoxic drug with a polymer nanocarrier. Such binding facilitates solubility in aqueous solutions, reduces systemic toxicity; and passively targets the drug directly into the tumour through the enhanced permeability and retention (EPR) effect. This thesis focuses on testing polymer conjugates based on N-(2-hydroxypropyl)methacrylamide (HPMA) carrying cucurbitacin D (CuD), a naturally occurring compound with potential anti-cancer activity. The mechanism of action is not elucidated yet, but several studies have depicted the inhibitory effect on signal transducer and activator of transcription 3 (STAT3) transcription factor. A STAT3 signalling pathway is overexpressed in several cancer cell lines and is also involved in the differentiation of myeloid- derived suppressor cells (MDSCs). We examined the therapeutic effect of the HPMA copolymers based on CuD in combined therapy with other polymer chemotherapeutics. CuD conjugates have shown in vitro cytotoxic effect on several model cancer cell lines. The combination with conjugates carrying doxorubicin...

Luffa cylindrica, popularly known as sponge gourd is a tropic and sub-tropical fibrous plant with fruits containing black seeds. The fruit is consumed by humans as a vegetable in many parts of Asia, while different parts of the plant are used for cosmetics and as medicine in many parts of the globe. The plant has been used in the treatment of many ailments including nose cancer, snake venom, wound healing, edema, enterobiasis, filaria, whooping cough, stomach upset, stomach pain and malaria. Many health-promoting compounds such as flavonoids (apigenin-7- glucuronide luteolin-7-O-β-D-glucuronide methyl ester, -O-feruloyl-β-D-glucose, luteolin-7-O-β-D-glucuronide methyl ester), phenolics acids (p-Coumaric, gallic, caffeic, chlorogenic), triterpenoids (oleanolic acid and echinocystic acid), saponins (Lucyoside A-M), tannins (catechin), ribosome-inactivating proteins (α- luffin), carotenoids (9 -cis neoxanthin, all-trans-lutein, all-trans-β-carotene), chlorophylls (chlorophyll a and b, pheophytin), cucurbitacin B and gypsogenin have been detected or isolated from different parts of the plants. Extracts of the plant and isolated compounds have wide spectrum pharmacological activities and have been shown to possess antiemetic, antidiabetic, antiviral, wound healing, anticancer, antipyretic, anti-inflammatory, antifungal, anti-bacteria, anthelmintic, hypoglycemic and antihyperglycemic, anti-inflammatory, antioxidant activity, and hepato-protective effects in animal models. However, further information is needed on its safety and mechanisms of action. The present article is an updated review of the ethnobotanical uses, pharmacological actions, phytochemistry, safety, and future application of Luffa cylindrica in translational medicine.