Radioprotective effects of quercetin and ethanolic extract of propolis in gamma-irradiated mice.

The aim of this study was to assess radioprotective effects of quercetin and the ethanolic extract of propolis (EEP) in CBA mice exposed to a single radiation dose 4 Gy (60Co). The mice were treated with 100 mg kg(-1) quercetin or EEP a day for three consecutive days either before (pre-treatment) or after gamma-irradiation (therapy). Leukocyte count was determined in blood drawn from the tail vein, and DNA damage in leukocytes was assessed using the alkaline comet assay. Genotoxic effects of the test compounds were also evaluated in non-irradiated mice. The levels of radioprotection provided by both test compounds were compared with those established in mice that were given chemical radioprotector S-(2-aminoethy1)isothiouronium bromide hydrobromide (AET). Mice that received pre-treatment were less sensitive to irradiation. Mice given the post-irradiation therapy showed a slight but not significant increase in total leukocyte count over irradiated negative control. Quercetin showed better protective properties than EEP in both pre-treatment and therapy, and activated a higher number of leukocytes in non-irradiated mice. The alkaline comet assay suggests that both natural compounds, especially when given as pre-treatment, protect against primary leukocyte DNA damage in mice. At tested concentrations, EEP and quercetin were not genotoxic to non-irradiated mice. AET, however, caused a slight but not significant increase in DNA damage. Although the results of this study show the radioprotective potential of the test compounds, further investigation is needed to clarify the underlying protection mechanisms.

Prevention of peritoneal carcinomatosis in mice with combination hyperthermal intraperitoneal chemotherapy and IL-2.

PURPOSE: The purpose of this study was to investigate the effect of local chemoimmunotherapy and hyperthermal intraperitoneal chemotherapy (HIPEC) in a mouse model of induced peritoneal carcinomatosis. MATERIAL AND METHODS: Peritoneal carcinomatosis in mice was produced by intraperitoneal implantation of MCa cells (5 x 10(3)). Interleukin-2 (4.1 x 10(4) IU/mouse) was injected into the abdominal cavity of mice at day 7 and 3 before implantation of tumour cells. Immediately after implantation of MCa cells mice were treated twice with 2 ml of saline that was heated either at 37 degrees C or 43 degrees C and cytostatics (doxorubicin 20 mg kg(-1), cisplatin 10 mg kg(-1), mitomycin 5 mg kg(-1), or 5-FU 150 mg kg(-1)). We followed the survival of animals and side effects appearing with different forms of treatment. RESULTS: Combined treatment with Interleukin-2 (IL-2) and cytostatics (5-FU, CIS or MIT) significantly affected the development of peritoneal carcinomatosis and increased the survival of mice (ILS% - 37 degrees C = 29.88, 199.32, and 108.52, ILS% - 43 degrees C = 62.69, 260.50, and 178.05, respectively). However, intraperitoneal chemotherapy on survival time of mice with DOX + IL-2 was ineffective as compared with DOX alone. CONCLUSION: We would like to stress that treatment with IL-2 prior to tumour diagnosis is not clinically practical, rather, the manuscript attempts to describe an experimental proof of principle. Results suggest the synergistic effect of hyperthermia, chemotherapy and immunotherapy; IL-2 significantly increases antitumor activity of hyperthermic chemotherapy and survival rate of mice with peritoneal carcinomatosis.

Evaluation of radioprotective effects of propolis and its flavonoid constituents: in vitro study on human white blood cells.

This in vitro study aimed to evaluate the possible radioprotective effects of the natural substances WSDP, caffeic acid, chrysin and naringin on gamma-irradiated human white blood cells. The effectiveness of tested compounds was evaluated using the alkaline comet assay, the analysis of structural chromosome aberration and the cytokinesis-block micronucleus assay. The results obtained by the alkaline comet study indicate favourable toxicity profiles of propolis and its polyphenolic components, and confirmed the radioprotective abilities comparable to the chemical radioprotector AET. WSDP and its polyphenolic components were able to reduce the number of necrotic cells. None of tested compounds induced significant genotoxicity, but all of them offered a quite measurable protection against DNA damage. WSDP was found to be the most effective in diminishing the levels of primary and more complex cytogenetic DNA damage in white blood cells. Considering its complex composition, to undoubtedly explain the underlying mechanisms of cyto/radioprotective effects, further studies are needed.

Evaluation of radioprotective effects of propolis and quercetin on human white blood cells in vitro.

This in vitro study aimed at investigating the possible radioprotective effects of natural substances propolis and quercetin on gamma-irradiated human white blood cells. The levels of primary DNA damage were studied by the alkaline comet assay, while the cytogenetic damage was evaluated using the analysis of structural chromosome aberration and cytokinesis-block micronucleus assay. The results obtained by all endpoints indicate acceptable toxicity profiles of propolis and quercetin in vitro, and also confirmed their radioprotective abilities. Propolis was found to be more effective in diminishing the levels of primary and more complex cytogenetic DNA damage in gamma-irradiated white blood cells. Data gathered in present study support the use of propolis and quercetin as non-toxic protective substances. However, to clarify the underlying mechanisms of their cyto/radioprotective activities, additional studies are necessary at both in vitro and in vivo levels.

Evaluation of the radioprotective effects of propolis and flavonoids in gamma-irradiated mice: the alkaline comet assay study.

The radioprotective effects of water-soluble derivate of propolis (WSDP) collected in Croatia, and single flavonoids, caffeic acid, chrysin and naringin in the whole-body irradiated CBA mice were investigated. Irradiation was performed using a gamma-ray source ((60)Co), and absorbed doses were 4 and 9 Gy. The efficiency of test components was evaluated when given intraperitoneally (i.p.) at dose of 100 mg kg(-1) for 3 consecutive days before and/or after irradiation. Moreover, possible genotoxic effects of all test components were assessed on non-irradiated animals. The higher efficiency of test components was observed when given preventively. The results suggest that propolis and related flavonoids given to mice before irradiation protected mice from lethal effects of whole-body irradiation and diminish primary DNA damage in their white blood cells as detected by the alkaline comet assay.

Assessment by survival analysis of the radioprotective properties of propolis and its polyphenolic compounds.

The radioprotective effects of propolis and polyphenolic compounds from propolis on the radiation-induced mortality of mice exposed to 9 Gy of gamma-irradiation were studied. Intraperitoneal (i.p.) treatment of mice at doses of 100 mg kg(-1) body weight of propolis (water or ethanolic extract; WSDP or EEP) or its polyphenolic compounds (quercetin, naringin caffeic acid, chrysin) consecutively for 3 d before irradiation, delayed the onset of mortality and reduced the symptoms of radiation sickness. All test compounds provided protection against hematopoietic death (death within 30 d after irradiation). The greatest protection was achieved with quercetin; the number of survivors at the termination of the experiment was 63%. According to statistical analyses by the Kaplan-Meier method and the log-rank test, a significant difference between test components and control was found (p<0.001). Treatment with test components after lethal irradiation was ineffective. These results suggest that propolis and its polyphenolic compounds given to mice before irradiation protect mice from the lethal effects of whole-body irradiation.

Adaphostin has significant and selective activity against chronic and acute myeloid leukemia cells.

Adaphostin is a tyrphostin that was designed to inhibit Bcr/Abl tyrosine kinase by altering the binding site of peptide substrates rather than that of adenosine triphosphate, a known mechanism of imatinib mesylate (IM). However, it has been shown that adaphostin-mediated cytotoxicity is dependent on oxidant production and does not require Bcr/Abl. We have tested adaphostin against both Philadelphia chromosome (Ph)-positive (K562, KBM5, KBM5-R [IM resistant KBM5], KBM7, and KBM7-R [IM-resistant KBM7]) and Ph-negative (OCI/AML2 and OCI/AML3) cells, and against cells from patients with chronic myeloid leukemia (CML) and acute myeloid leukemia (AML). Adaphostin significantly inhibited growth of all cell lines (50% inhibition of cell proliferation [IC50] 0.5-1 microM) except K562 (IC50 13 microM). Ph-positive IM-resistant cell lines showed significant cross resistance to adaphostin. Simultaneous or sequential treatment with adaphostin and IM did not exert a synergistic effect in any KBM line. Adaphostin induced superoxide and apoptosis in a dose-dependent and time-dependent fashion in both Ph-positive and Ph-negative cells. Adaphostin selectively inhibited colony growth of cells from CML (IM-sensitive and IM-resistant) and AML patients. Analysis of tyrosine phosphorylated proteins after treatment with adaphostin revealed alternate effects in different cells consistent with the modulation of multiple targets. In conclusion, adaphostin showed significant and selective activity against CML and AML cells and its development for clinical testing is warranted.

Direct and indirect mechanism(s) of antitumour activity of propolis and its polyphenolic compounds.

The immunomodulatory actions of a water-soluble derivative of propolis (WSDP) and two components of propolis, caffeic acid (CA) and caffeic acid phenethyl ester (CAPE) were investigated. Oral administration (50 mg/kg) of WSDP, CA, and CAPE enhanced the weight and cellularity of the spleen (p<0.05, p<0.01) of treated mice. The response of spleen cells to polyclonal mitogens (PHA, Con A, PWM) was also increased in mice treated with WSDP as compared to control (p<0.01); in contrast, the response of spleen cells of mice treated with CA were significantly suppressed (p<0.001). The colony forming ability of HeLa cells plated on monolayers of macrophages was completely inhibited by peritoneal macrophages from mice receiving either WSDP, CAPE, or CA. Macrophages from treated mice also inhibited [3H]TdR incorporation into HeLa cells in vitro. Testing for the possible presence of NO in the supernatants of 24 hours cultured macrophages activated with either compound revealed that the toxicity of these cells to HeLa cells was in part due to the production of NO. Tumour growth was suppressed by WSDP and its polyphenolic compounds given orally to mice. Local presence of CA, and CAPE in the tissue, caused a significant delay of tumour formation. Based on these results, we postulate that the antitumour activity of the test compounds includes pronounced immunomodulatory activity mainly due to the augmentation of non-specific antitumour resistance in mice via macrophage activation and the production of soluble factors by those cells which may interfere with either cells of the immune system or directly by tumour cells.

Antitumor, hematostimulative and radioprotective action of water-soluble derivative of propolis (WSDP).

Several studies suggest that dietary supplementation with antioxidant can influence the response to chemotherapy as well as the development of adverse side effects caused by treatment with chemotherapeutic agents. Using CBA mouse model, we investigated a clinically potential use of a water-soluble derivative of propolis (WSDP) in the treatment of various cytopenias induced by radiation and/or chemotherapy. Also, the antimetastatic efficiency of WSDP given intraperitoneally alone or in combination with chemotherapeutic agents and their effects on the blood leukocytes count as well as on hematopoiesis were studied. Tumor was a transplantable mammary carcinoma (MCa) of CBA mouse. Metastases in the lung were generated by injecting viable tumor cells intravenously (iv). WSDP (50 or 150 mg/kg) exerted a significant antimetastatic effect (P < 0.001) when given either before or after tumor cell inoculation. In combined treatment WSDP and Epirubicin profoundly inhibited metastasis formation; this synergistic effect is maximal when Epirubicin and WSDP were administrated after tumor cell inoculation. Positive outcome of combined treatment with WSDP and Epirubicin was also found regarding the number of red and white blood cells in peripheral blood while in mice treated with Epirubicin alone the significant drop in all hematological parameters was noticed on day 13 after tumor cell inoculation. Furthermore, when WSDP (50 mg/kg) was given perorally (po) for 20 consecutive days an increased number of exogenous CFUs was found in treated mice. WSDP given either for 20 or 40 days increased cellularity of hematopoietic tissue and the number of leucocytes in peripheral blood; prolonged treatment with WSDP also elevated myeloid and megakaryocytic types of CFUs. To conclude, these findings indicate that the combination of WSDP with chemotherapeutics could increase the antimetastatic potential of chemotherapeutic agents; these findings suggest the benefits of potential clinical trials using WSDP combined with chemotherapeutic agents in order to maximize their antitumor activity and minimize postchemotherapeutic or radiotherapeutic deteriorated reactions.

Effects of local administration of propolis and its polyphenolic compounds on tumor formation and growth.

Many dietary constituents are chemopreventive in animal models, and experiments with cultured cells are revealing various potential mechanisms of action. Compounds classified as blocking agents can prevent, or greatly reduce, initiation of carcinogenesis, or suppressing agents can act on cell proliferation. Caffeic acid (CA) and caffeic acid phenethyl ester (CAPE), members of the polyphenolic compounds, are present in high concentrations in medicinal plants and propolis, a natural beehive product. A water-soluble extract of propolis (WSDP) and two components of propolis, CA and CAPE were investigated for direct antitumor activity in vivo and in vitro. The local presence of CA and CAPE in the tissue caused a significant delay in tumor formation and increased life span 29.30 to 51.73%, respectively. CA and CAPE, but not WSDP, significantly suppressed human HeLa cervical carcinoma cell proliferation in vitro. Based on these results, we postulate that the antitumor activity of polyphenolic compounds includes direct cytotoxic effects on tumor cells.

Water-soluble derivative of propolis and its polyphenolic compounds enhance tumoricidal activity of macrophages.

Many plants and the plant-derived honeybee propolis have shown biological activities like immunomodulation and antitumor effect. The effect of two water-soluble propolis derivatives (WSDP) from Croatia and Brazil, caffeic acid, quercetin, chrysin and naringenin which are present in WSDP was assessed on the development of Ehrlich ascites tumor (EAT). The compounds (50 mgkg(-1)) were given by gastric intubations (po) 2 h prior to the intraperitoneal injection of EAT (2x10(6)) cells. It was observed that WSDP and its compounds effectively inhibited tumor growth and proliferation of EAT. The volume of ascitic fluid induced by EAT cells and total number of cells present in the peritoneal cavity was markedly reduced in EAT-bearing mice treated with test components. Treatment with test components increased the number of polymorphonuclear (PMN) cells and decreased the number of macrophages in the peritoneal cavity of treated animals. The macrophage spreading activity revealed that WSDP and all test compounds affected the functional state of macrophages increasing their tumoricidal activity. The effect of WSDP was most pronounced suggesting synergistic effect of components present in WSDP. It is likely that part of the antitumor efficacy of the assayed components against EAT cells was the results of increased macrophage activity.

Synergistic antitumor effect of polyphenolic components of water soluble derivative of propolis against Ehrlich ascites tumour.

Effect of two preparation (Croatian and Brazilian) of water-soluble derivative of propolis (WSDP), caffeic acid, quercetin, chrysin, naringenin (components present in WSDP) on the development of Ehrlich ascites tumour (EAT) was evaluated. Test components (50 mg/kg) were given perorally or intraperitoneally 2 h prior the intraperitonel injection of EAT (2 x 10(6)) cells. It was observed that all test compounds effectively inhibited tumour growth and the proliferation of EAT. The volume of ascitic fluid induced by EAT cells and total number of cells present in the peritoneal cavity was markedly reduced in EAT-bearing mice treated with test components. In treated mice the number of polymorphonuclear (PMN) cells in the peritoneal cavity was increased while the number of macrophages was decreased. The macrophage spreading activity revealed that WSDP and all test compounds affected the functional state of macrophages increasing their tumorcidal activity; the effect of WSDP was most pronounced indicating synergistic effect of components present in WSDP. Antitumor activity of WSDP may be the result of different specific mechanism(s) of flavonoids present as compared to individual flavonoid given alone. It is likely that the part of antitumor efficacy of test components against EAT cells was the results of increased activity of macrophages.

Immunomodulatory and antimetastatic action of propolis and related polyphenolic compounds.

The effect of polyphenolic compounds isolated from propolis and propolis itself was investigated on the growth and metastatic potential of a transplantable mammary carcinoma (MCa) of CBA mouse. Metastases in the lung were generated by intravenous injection of tumor cells (2 x 10(5)). A water-soluble derivative of proplis (WSDP), caffeic acid (CA), caffeic acid phenethyl ester (CAPE) and quercetin (QU) were given to mice per os before tumor cells inoculation. Tested compounds significantly decreased the number of tumor nodules in the lung. According to the results obtained the antitumor activity of tested compounds can be related to the immunomodulatory properties of the compounds, their cytotoxicity to tumor cells, and their capacity to induce apoptosis and necrosis. The experimental data support that WSDP, CA, CAPE and QU could be potentially useful in the control of tumor growth in experimental models.

Tetrakis(tetramethylammonium) dodeca-mu-chloro-hexachloro-octahedro-hexatantalate chloride.

The title compound, (C(4)H(12)N)(4)[Ta(6)Cl(18)]Cl, crystallizes in the cubic space group Fm-3m. The crystal structure contains two different types of coordination polyhedra, i.e. four tetrahedral [(CH(3))(4)N](+) cations and one octahedral [(Ta(6)Cl(12))Cl(6)](3-) cluster anion, and one Cl(-) ion. The presence of three different kinds of Cl atoms [bridging (mu(2)), terminal and counter-anion] in one molecule makes this substance unique in the chemistry of hexanuclear halide clusters of niobium and tantalum. The Ta(6) octahedron has an ideal O(h) symmetry, with a Ta-Ta interatomic distance of 2.9215 (7) A.

Toward generating simpler QSAR models: nonlinear multivariate regression versus several neural network ensembles and some related methods.

In this study we want to test whether a simple modeling procedure used in the field of QSAR/QSPR can produce simple models that will be, at the same time, as accurate as robust Neural Network Ensemble (NNE) ones. We present results of application of two procedures for generating/selecting simple linear and nonlinear multiregression (MR) models: (1) method for selecting the best possible MR models (named as CROMRsel) and (2) Genetic Function Approximation (GFA) method from the Cerius2 program package. The obtained MR models are strictly compared with several NNE models. For the comparison we selected four QSAR data sets previously studied by NNE (Tetko et al. J. Chem. Inf. Comput. Sci. 1996, 36, 794-803. Kovalishyn et al. J. Chem. Inf. Comput. Sci. 1998, 38, 651-659.): (1) 51 benzodiazepine derivatives, (2) 37 carboquinone derivatives, (3) 74 pyrimidines, and (4) 31 antimycin analogues. These data sets were parameterized with 7, 6, 27, and 53 descriptors, respectively. Modeled properties were anti-pentylenetetrazole activity, antileukemic activity, inhibition constants to dihydrofolate reductase from MB1428 E. coli, and antifilarial activity, respectively. Nonlinearities were introduced into the MR models through 2-fold and/or 3-fold cross-products of initial (linear) descriptors. Then, using the CROMRsel and GFA programs (J. Chem. Inf. Comput. Sci. 1999, 39, 121-132) the sets of I (I < or = 8, in this paper) the best descriptors (according to the fit and leave-one-out correlation coefficients) were selected for multiregression models. Two classes of models were obtained: (1) linear or nonlinear MR models which were generated starting from the complete set of descriptors, and (2) nonlinear MR models which were generated starting from the same set of descriptors that was used in the NNE modeling. In addition, the descriptor selection method from CROMRsel was compared with the GFA method included in the QSAR module of the Cerius2 program. For each data set it has been found that the MR models have better cross-validated statistical parameters than the corresponding NNE models and that CROMRsel selects somewhat better MR models than the GFA method. MR models are also much simpler than NNEs, which is the important surprising fact, and, additionally, express calculated dependencies in a functional form. Moreover, MR models were shown to be better than all other models obtained by different methods on the same data sets ("old" multivariate regressions, functional-link-net models, back-propagation neural networks, genetic algorithm, and partial least squares models). This study also indicated that the robust NNE models cannot generate good models when applied on small data sets, suggesting that it is perhaps better to apply robust methods (like NNE ones) on larger data sets.

Inhibition of mammary carcinoma cell proliferation in vitro and tumor growth in vivo by bee venom.

The possible tumor growth- and metastasis-inhibiting effects of bee venom in mice and in tumor cell cultures were studied. The tumor was a transplantable mammary carcinoma (MCa) of CBA mouse. Intravenous administration of bee venom to mice significantly reduced the number of metastases in the lung. However, subcutaneous administration of bee venom did not reduce the number of lung metastases, indicating that the antitumor effect of the venom could be highly dependent on the route of injection as well as close contact between the components of the venom and the tumor cells, as was shown by in vitro studies on MCa cells. We also observed variations in immunological parameter induced by bee venom. We proposed that bee venom has an indirect mechanism of tumor growth inhibition and promotion of tumor rejection that is based on stimulation of the local cellular immune responses in lymph nodes. Apoptosis, necrosis, and lysis of tumor cells are other possible mechanisms by which bee venom inhibits tumor growth.

Immunomodulation by water-soluble derivative of propolis: a factor of antitumor reactivity.

The antimetastatic efficacy of a water-soluble derivative of propolis (WSDP) was studied. Tumor was a transplantable mammary carcinoma of CBA mouse. Metastases in the lung were generated by 2 x 10(5) viable tumor cells i.v. WSDP was given intraperitoneally at doses of 50 or 150 mg/kg before or after tumor cell inoculation. Therapies reduced the number of metastases in the lung and tumor growth was suppressed significantly by WSDP. It is likely that antimetastatic activity of the WSDP is mainly mediated by immunomodulatory activity. Changes in several immunological parameters such as production of lymphocyte activating factor by peritoneal macrophages and the efficacy of those macrophages to kill tumor cell in vitro, responses of lymphocytes to mitogen, and weight and cellularity of spleen, respectively, correlated well with antimetastatic properties of the WSDP. Based on results we postulate that the antimetastatic activity of propolis includes a pronounced immunomodulatory activity mainly toward augmentation of nonspecific antitumor resistance in mice via macrophage activation.

Inhibitory effect of water-soluble derivative of propolis and its polyphenolic compounds on tumor growth and metastasizing ability: a possible mode of antitumor action.

Polyphenolic compounds are widely distributed in the plant kingdom and display a variety of biological activities, including chemoprevention and tumor growth inhibition. Propolis is made up of a variety of polyphenolic compounds. We compared how the routes of administration of polyphenolic compounds deriving from propolis and of propolis itself affect the growth and metastatic potential of a transplantable mammary carcinoma (MCa) of the CBA mouse. The influence of tested compounds on local tumor growth was also studied. Metastases in the lung were generated by 2 x 10(5) tumor cells injected intravenously (IV). A water-soluble derivative of propolis (WSDP) and polyphenolic compounds (caffeic acid, CA, and CA phenethyl ester, CAPE) were given to mice per os (PO) or intraperitoneally (IP) before or after tumor cell inoculation. Tested compounds significantly decreased the number of lung colonies. When mice were inoculated with 10(5) MCa cells in the exact site of subcutaneous injection of different doses of WSDP, CA, or CAPE, tumor growth was inhibited, and survival of treated mice was prolonged. Antitumor activity, according to the results obtained, is mostly related to the immunomodulatory properties of the compounds and their capacity to induce apoptosis and necrosis. In conclusion, results presented here indicate that WSDP, CA, and CAPE could be potential useful tools in the control of tumor growth in experimental tumor models when administrated PO; because PO administration is the easiest way of introducing a compound used for prevention and/or cure of any disease, it is likely that this article has reached the goal of the investigation.