Immunomodulatory effects of lactic acid bacteria vary with strain and may vary with growth phase and medium. The ability of different lactobacilli strains (Lactobacillus helveticus R0052, L. rhamnosus R0011, L. rhamnosus GG) at different growth phases to modulate macrophage and intestinal epithelial cell cytokine production following a pro-inflammatory challenge was examined. Modulation of cytokine production by human macrophage cell lines (U-937) and intestinal epithelial cells (HT-29) induced by Tumor Necrosis Factor α was assayed by ELISA for interleukin-8 (IL-8). Granulocyte-macrophage colony stimulating factor (GM-CSF) production was assayed by ELISA in the HT-29 cell line. Strain-dependent differences were observed in the ability of viable bacteria and spent de Mann-Rogosa- Sharpe (MRS) broths from log versus stationary growth phase in HT-29 and U-937 cells. Overall, variation in the immunomodulatory activity of these lactic acid bacteria and spent broths reflects not only strain variation but potentially also differences in growth phase and substrate. / UOIT

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O cÃncer à uma doenÃa que afeta cada vez mais um nÃmero maior de pessoas em todo o mundo. As terapias atuais utilizadas para o tratamento do cÃncer sÃo ainda insatisfatÃrias. Produtos naturais tÃm sido avaliados para seleÃÃo de compostos ativos, capazes de reduzir os tumores malignos de uma forma mais eficiente e com menos efeitos indesejÃveis. O polissacarÃdeo sulfatado extraÃdo da alga Champia feldmannii (Cf-PLS) foi testado para avaliaÃÃo do seu potencial antitumoral e imunoestimulante. AlÃm disso, foram feitos testes de toxicidade do fÃgado, rins e baÃo apÃs o tratamento com Cf-PLS. Os resultados demonstraram que Cf-PLS nÃo apresenta citotoxicidade in vitro, mas à capaz de reduzir o tumor Sarcoma 180 implantado em camundongos em 48,16% e 48,62% nas doses de 10 e 25mg/kg, respectivamente, e reduz 68,32% quando adiministrado juntamente com 5-Fluorouracil (5-FU). As anÃlises do fÃgado e rins revelaram que houve certa toxicidade no rim, com Ãreas de necrose tubular aguda na maior dose. Os testes da perfusÃo renal revelaram que Cf-PLS causa aumento da pressÃo de perfusÃo, resistÃncia vascular renal, ritmo de filtraÃÃo glomerular e fluxo urinÃrio, alÃm da excreÃÃo de sÃdio, cloreto e potÃssio. NÃo houve alteraÃÃes nos percentuais de transporte totais ou tubular proximais de sÃdio, cloreto ou potÃssio. Houve discreta deposiÃÃo protÃica nos glomÃrulos e tÃbulos renais. NÃo houve alteraÃÃes nas anÃlises bioquÃmicas e os testes hematolÃgicos revelaram uma leucopenia causada por 5-FU, entretanto esta foi revertida pelo tratamento com Cf-PLS. TambÃm foi demonstrado que Cf-PLS age como agente imunoestimulante e imunomodulador, aumentando a produÃÃo de anticorpos totais e especÃficos contra Cf-PLS e OVA, aumentando tambÃm a polpa branca e o nÃmero de megacariÃcitos nos baÃos dos animais tratados e induzindo a migraÃÃo de neutrÃfilos para a cavidade peritoneal de camundongos. Pode-se concluir que Cf-PLS apresenta atividade antitumoral e que isso pode estar relacionado com suas propriedades imunoestimulantes. / Cancer is a desease that occurs in a larger number of people each year. The therapies used to treat it are still not satisfatory. Natural products have been studied to select new compounds capable of reducing tumours and with fewer side effects. The sulfated polysaccharide isolated from the seaweed C. feldmannii (Cf-PLS) was investigated for its antitumor and immunostimulating properties and also for the toxicological aspects related to Cf-PLS treatment. The Cf-PLS did not show any significant in vitro cytotoxic effect, but showed a strong in vivo antitumor effect. The inhibition rates of sarcoma 180 tumor development were 48.16 % and 48.62% at the doses of 10 and 25 mg/kg, respectively, and 68.32% when treated together with 5-fluorouracil (5-FU). The histopathological analysis of liver and kidney showed that the kidneys were affected by Cf-PLS-treatment, presenting some focal areas of acute tubular necrosis at the higher dose. Cf-PLS caused considerable changes in renal physiology, as shown by an increase in parameters such as perfusion pressure, renal vascular resistance, glomerular filtration rate, urinary flow and sodium, chloride and potassium excretion. Neither enzymatic activity of alanine aminotransferase, urea nor creatinin levels were significantly altered. In hematological analyses, leucopeny was observed after 5-FU treatment, but this effect was prevented when the treatment was associated with the Cf-PLS. It was also demonstrated that Cf-PLS acts as an immunomodulatory agent, raising the production of specific antibodies, and also increasing the production of OVA-specific antibodies. In addition, it induced a discreet increase of the white pulp and nest of megakaryocytic in spleen of treated mice and the neutrophil migration to the intraperitoneal cavity of mice. In conclusion, Cf-PLS has some interesting antitumour activity that could be associated with its immunostimulanting properties.

Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-22T14:46:07Z No. of bitstreams: 5 André Barreiros 5.pdf: 1310338 bytes, checksum: d59dc4bf426cac1e442be4eb9ee6d894 (MD5) André Barreiros 4.pdf: 1401764 bytes, checksum: 07e4fdbbe9dd39da5506e4d366f674d3 (MD5) André Barreiros 3.pdf: 1612776 bytes, checksum: 615c8ab2914ba19f8eb7af1b4c5d83cf (MD5) André Barreiros 2.pdf: 1211895 bytes, checksum: c2f0cb1c002d0263b0c0a42dbdda2a14 (MD5) André Barreiros 1.pdf: 239109 bytes, checksum: d5ef73879c018bc308a7c7bb697a9ebc (MD5) / Made available in DSpace on 2013-04-22T14:46:07Z (GMT). No. of bitstreams: 5 André Barreiros 5.pdf: 1310338 bytes, checksum: d59dc4bf426cac1e442be4eb9ee6d894 (MD5) André Barreiros 4.pdf: 1401764 bytes, checksum: 07e4fdbbe9dd39da5506e4d366f674d3 (MD5) André Barreiros 3.pdf: 1612776 bytes, checksum: 615c8ab2914ba19f8eb7af1b4c5d83cf (MD5) André Barreiros 2.pdf: 1211895 bytes, checksum: c2f0cb1c002d0263b0c0a42dbdda2a14 (MD5) André Barreiros 1.pdf: 239109 bytes, checksum: d5ef73879c018bc308a7c7bb697a9ebc (MD5) Previous issue date: 2005 / O presente trabalho descreve o estudo fitoquímico de Dioclea violacea Mart. além da avaliação das atividades antioxidante e imunomoduladora das substâncias isoladas. Dioclea violacea é uma trepadeira pertencente à família Leguminosae (Fabaceae), subfamília Faboideae (Papilionoideae), tribo Phaseoleae, que ocorre no litoral desde a Guiana até o estado de São Paulo. O caule de um espécime foi coletado no município de Umburanas, Bahia, em área de vegetação de caatinga e relevo de tabuleiro. Após secagem e moagem o material foi submetido à maceração com metanol. O extrato metanólico obtido foi particionado fornecendo os extratos hexânico, clorofórmico e acetato de etila. Os extratos foram submetidos a purificação separadamente, sendo seus constituintes isolados e purificados através de técnicas de CC e CCDP em gel de sílica 60, 60H, 60PF, Poliamida 6 e 11 e permeação em gel de Sephadex LH20. Deste modo, as substâncias isoladas tiveram suas estruturas elucidadas através da análise de dados de RMN de 1H, 13C incluindo experimentos DEPT, ?nOe diff?, além de técnicas bidimensionais como HETCOR, HOMO/COSY, HMQC, HMBC, NOESY, auxiliadas por EMIE, FAB, UV, IV, [a]D25 e CD. Do extrato hexânico foram isolados e identificados a-tocoferol, estigmast-4-en-3-ona, b-sitosterol, estigmasterol, lupeol e b-amirina. Do extrato clorofórmico foram isolados ácido oleanólico, a nova flavanona 7,4?-diidroxi-6-metoxiflavanona, além das 7-hidroxi-6-metoxiflavanona, 5,7-diidroxiflavanona, 5,7-diidroxi-8-metoxiflavanona, 7-hidroxiflavanona, 4?,7-diidroxiflavanona, 7,3?,4?-triidroxiflavanona já anteriormente isoladas de outras fontes. Além disso, foram também isolados deste extrato o 7-hidroxi-6-metoxiflavanonol, 2?,4? diidroxichalcona, 2?,4,4?-triidroxi-3-metoxichalcona, 2?,3,4,4?-tetraidroxichalcona, além da lactona lasiodiplodina e de um novo biflavonóide a,b?-epoxi,-2,2?,4?-triidroxichalcona-(b®4?)-7,4?-diidroxi-6-metoxiflavanona. Enquanto que, do extrato acetato de etila foram isolados a epicatequina, a proantocianidina do tipo A denominada 3?,4?,7-triidroxiflavana-(2b®7,4b®8)-3-prenil-fustina, e outras duas proantocianidinas do tipo A2; epicatequina-(2b®7,4b®8)-epicatequina e epigalocatequina-(2b®7,4b®8)-epicatequina. As substâncias isoladas foram submetidas a testes de atividade antioxidante pelos métodos de inibição da autooxidação do b-caroteno, e seqüestro do radical livre DPPH, sendo que a epicatequina e as proantocianidinas epicatequina-(2b®7,4b®8)-epicatequina e epigalocatequina-(2b®7,4b®8)-epicatequina foram as mais ativas. Algumas das substâncias foram submetidas a testes de atividade imunomoduladora pelos métodos de inibição da proliferação de linfócitos e inibição da síntese de NO, onde a 7 hidroxiflavanona demonstrou maior atividade. A substância mais ativa 7-hidroxiflavanona foi sintetizada a partir da reação de esterificação do ácido cinâmico com o resorcinol em presença de ácido polifosfórico, seguida de rearranjo de Fries e ciclização, porém com baixo rendimento (1,6%). Os produtos principais da reação foram a 7-hidroxi-3,4-diidro-4-fenilcumarina (68,7%) e a 5-hidroxi-3,4-diidro-4-fenilcumarina (11,2%). / Salvador

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O cÃncer à uma doenÃa que afeta cada vez mais um nÃmero maior de pessoas em todo o mundo. As terapias atuais utilizadas para o tratamento do cÃncer sÃo ainda insatisfatÃrias. Produtos naturais tÃm sido avaliados para seleÃÃo de compostos ativos, capazes de reduzir os tumores malignos de uma forma mais eficiente e com menos efeitos indesejÃveis. O alginato extraÃdo da alga Sargassum vulgare C. AGARDH (SVHV) foi testado para avaliaÃÃo do seu potencial antitumoral e imunoestimulante. AlÃm disso, foram feitos testes de toxicidade do fÃgado, rins e baÃo apÃs o tratamento com SVHV. Os resultados demonstraram que SVHV nÃo apresenta citotoxicidade in vitro, mas à capaz de reduzir o tumor Melanoma B-16 implantado em camundongos em 75,8% na dose de 25mg/kg/dia, quando administrado por via intraperitoneal (p < 0,05), enquanto nÃo houve inibiÃÃo por via oral. As anÃlises do fÃgado e rins revelaram que houve toxicidade no rim, com Ãreas de hemorragia glomerular e intersticial nos camundongos tratados com SVHV. Essas alteraÃÃes sÃo, entretanto, consideradas reversÃveis. As anÃlises bioquÃmicas, revelaram um aumento nos nÃveis sÃricos da alanina aminotransferase (ALT) nos grupos com tumor ou tratado com SVHV por via oral e os testes hematolÃgicos revelaram um aumento na porcentagem de neutrÃfilos nestes grupos, enquanto que a porcentagem de monÃcitos foi reduzida nos grupos com tumor e nos tratados com SVHV por via intraperitoneal. TambÃm foi demonstrado que SVHV age como agente imunoestimulante e imunomodulador, ativando macrÃfagos in vitro, assim como sendo capaz de causar inflamaÃÃo atravÃs do teste do edema de pata e induzir a migraÃÃo de neutrÃfilos para a cavidade peritoneal. Conclui-se entÃo que SVHV apresenta atividade antitumoral e que esta atividade està relacionada com suas propriedades imunoestimulantes. / Cancer is a disease that occurs in a larger number of people each year. The therapies used to treat it are still not satisfatory. Natural products have been studied to select new compounds capable of reducing tumours and with fewer side effects. The alginate isolated from the seaweed S. vulgare (SVHV) was investigated for its antitumor and immunostimulating properties and also for the toxicological aspects related to SVHV treatment. The SVHV did not show any significant in vitro cytotoxic effect, but showed a strong in vivo antitumor effect. The inhibition rates of Melanoma B-16 tumor development was 75,8% at the dose of 25 mg/kg/day when treated by intraperitoneal route (p < 0,05). The histopathological analysis of liver and kidney showed that the kidneys were affected by SVHV-treatment, presenting some hemorragic areas. The enzymatic activity of alanine aminotransferase, was augmented in mice with tumor or treated with SVHV by oral route. In hematological analyses, these groups showed a higher percentage of neutrophils, while the group with tumor or treated with SVHV by intraperitoneal route showed a reduction in the percentage of monocytes. It was also demonstrated that SVHV acts as an immunomodulatory agent, stimulating macrophages in vitro, causing paw edema in rats and neutrophil migration to the intraperitoneal cavity. In conclusion, SVHV has some interesting antitumour activity that is associated with its immunostimulanting properties.

Glycodelin, a homodimeric glycoprotein belonging to the lipocalin superfamily, is synthesised predominantly by the cells of the reproductive system of certain primates including humans. Of the four different known glycoforms of the molecule, glycodelin A (GdA), secreted by the glandular epithelial cells of the endometrium in response to progesterone, is involved in the immunosuppression of the maternal immune response to the semi-allograft fetus. GdA secretion onsets few days after ovulation. In the absence of fertilization, GdA levels drop, but subsequent to a successful fertilization, the concentrations peak till the 12th week of pregnancy and fall steadily to low levels. The importance of GdA has been implicated in implantation, endometrial receptivity, trophoblast invasion and differentiation, and modulating the functions of almost all immune cells. GdA has profound influence on the activity of T cells. It inhibits the proliferation of T cells, induces apoptosis in activated T cells, inhibits the IL-2 production and leads to skewing of the Th-1/Th-2 balance towards Th-2 type of immune response. Cytotoxic T lymphocytes are more resistant to the induction of apoptosis by GdA, but, it suppresses their cytolytic activity Additionally, GdA induces apoptosis in monocytes and natural killer (NK) cells, inhibits the proliferation of B cells and induces tolerogenic phenotype in dendritic cells. Clinical studies showing that women undergoing recurring spontaneous abortions have low levels of GdA supports its role in prevention of fetus rejection. The immunomodulatory activity of Gd resides in the protein backbone, however, apart from GdA and GdF which have similar oligosaccharide chains, other glycoforms do not possess this activity. Glycosylation seems to dictate the stability, folding and activity of Gd. In absence of glycosylation, the expression of the recombinant Gd is compromised and the protein is improperly folded while over-mannosylation of Gd impairs its immunomodulatory function. Additionally, sialylation seen on the glycan chain regulates the activity. Therefore, in order to obtain adequate amounts of active recombinant Gd (rGd), expression of the protein was attempted in three different systems, insect, yeast and bacteria (Chapter 1). In all of the described systems, the rGd protein was found apoptotically active. The protein expressed in the Sf21 insect cells was demonstrated to be differentially glycosylated compromising the activity. Hence, a genetically modified yeast strain, Pichia pastoris SuperMAN5 was explored for expression. Though presence of a single glycosylated protein species was observed in small-scale cultures, similar to the case of Sf21 cell expression, differentially glycosylated proteins were detected in large-scale fermentation and even the yield was low. Eventually, mutant Gd, modified to increase the stability and aid in proper protein folding, was expressed in E.coli and demonstrated to be able to induce apoptosis in Jurkat cells (T cell leukemia cell line). This active rGd was used for further studies. The immunomodulatory function of GdA during pregnancy protects the semi-allograft fetus from rejection by the maternal immune system. In the process, GdA tweaks the T cell immune response from pro-inflammatory to anti-inflammatory in a specific and localized manner. Allograft rejection seen during mis-match transplantations is basically a pro-inflammatory condition which is mediated by the activation of cellular immune response, NK cell cytotoxicity and antibody-dependent immune response, the same processes that are suppressed for a successful pregnancy. Chapter 2 discusses whether it is feasible to use Gd to prevent allograft rejection. Killing of target graft cells by the cytotoxic T lymphocytes (CTLs) predominantly presides acute graft rejection. GdA treatment has been shown to suppress the cytotoxicity of in vitro generated CTLs. On this basis, the earlier study was translated to in vivo conditions by establishing an allograft nude mouse model. The tumor rejection mediated by the action of in vitro generated cytotoxic alloactivated PBMCs in the nude mouse imitated the allograft rejection. A heterogenous population of immune cells with the predominance of CTLs was chosen to accommodate a more interactive immune response in the tumor microenvironment and enabled the study of other cells which may contribute to the rejection. Reactivation and proliferation of CD4+ and CD8+ T cells following their infiltration in the tumor validated our hypothesis. On treatment with rGd, the cytotoxicity of the alloactivated PBMCs was suppressed, thereby inhibiting the tumor rejection in the nude mouse. Real time PCR analysis showed that rGd treatment was able to affect the functions of the immune cells in vivo. It decreased the T cell population most probably by inducing apoptosis. As expected, the reduction was more prominent in case of CD4+ T cells than CD8+ T cells. The their expression of key molecules responsible for the cytotoxicity such as IL-2, granzyme B and EOMES, was observed to be downregulated by rGd. Concomitantly, decreased levels of pro-inflammatory cytokines, TNFα and IL-6 were also seen. Expression of Foxp3, marker for regulatory T cells, was upregulated in the tumor infiltrating immune cells suggesting an expansion of the concerned population upon rGd treatment. Overall, rGd seems to suppress the cellular immune response to the tumor by modulating the T cell population and their functions. Since, T cell-dependent immune response is central to allograft rejection, the ability of rGd to regulate it could be of therapeutic use in the management of allograft rejection. NK cells are essential for the maintenance of pregnancy, evident from their abundance (70% of total leukocytes) at the first trimester decidua. The third chapter focuses on how Gd regulates the NK cell function. The cytokine production from CD56bright subset of NK cells and their interaction with the HLA antigens expressed by the trophoblast cells helps in creating a favourable environment for the growth of the fetus. It is important to note that the NK cell population present in the decidua exclusively express Gd, implicating a role of Gd in their differentiation from the peripheral CD56bright cells. However, an increased number of CD56dimCD16+ cells in the peripheral blood dictates a negative outcome for the pregnancy. The study, presented in Chapter 3, demonstrated that rGd treatment induces caspase-dependent apoptosis in the activated CD56dimCD16+ cells and reduces their cytotoxicity by downregulating granzyme B and IFNγ production. Similar effect of rGd is also seen on the NKT cells characterised as CD3+CD56dimCD16-. Furthermore, in YT-Indy cells, an activated NK cell line, it was shown that the induction of apoptosis by rGd involves Ca2+ signalling which could explain why Gd affects activated immune cells only. This study therefore reinforces the role of Gd in modulating the NK cell activity during pregnancy. Cytotoxicity of NK and NKT cells also plays an important role during allograft rejection. Decrease in the mRNA levels of CD56 upon rGd treatment in the allograft mouse model indicates that the effect of Gd on NK cells observed in cell culture system can be translated to in vivo conditions. In conclusion, suppression of the cellular immune response and NK cell mediated cytotoxicity by rGd could potentiate its’ probable use in the management of allograft rejection. .

Made available in DSpace on 2015-05-14T13:00:09Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1776418 bytes, checksum: 744ac3ac5030bc552fceb05b70d06ca5 (MD5) Previous issue date: 2015-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Leishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished efficacy due to development of resistance by the parasites has a negative impact on the current treatment options. Thus, the search for a new, effective and safer antileishmanial drug becomes of paramount importance. Compounds derived from natural products may be a better and cheaper source in this regard. This study evaluated the in vitro, in vivo and in silico antileishmanial activity of Spiranthera odoratíssima (Rutaceae) fractions and isolated compounds, using promastigote and amastigote forms of different Leishmania species. J774 A.1 macrophage was used as the parasite host cell for the in vitro assays. Evaluations of cytoxicity, nitric oxide (NO), interleukin-10, interleukin-12, IFN-γ were obtained in vitro and expression of p38 mitogen activated protein kinase (p38 MAPK), NF-κB (p50 and p65) was studied by western blotting.in vivo and in silico analysis were carried out. In vitro experiments showed that the fruit hexanic fraction (Fhf) and its alkaloid skimmianine (Skm) have a significant (P<0·001) effect against L. braziliensis. This anti-L. braziliensis activity of Fhf and Skm was due to increased production of NO and attenuation of IL-10 production in the macrophages in contrast of IL-12 and IFN-γ levels increased at concentrations ranging from 1·6 to 40·0 μg/ml. Fhf and Skm showed expression of p38 and NF-κB, pathways involved in the production of Th1 cytokines and nitric oxide. In vivo testing showed reduction in lesion size in mice infected with L. braziliensis, as well as reduction in parasite burden in linfonode and spleen. The in silico assay demonstrated significant interaction between Skm and amino acid residues of NOS2.Skm is thus a promising drug candidate for L. braziliensis due to its potent immunomodulatory activity. / A leishmaniose é uma doença negligenciada cujo tratamento disponibilizado está associado a uma série de efeitos tóxicos, alto custo e diminuição da eficácia terapêutica devido ao aumento da resistência pelos parasitas. Assim, a pesquisa de novas drogas mais eficazes e seguras torna-se de grande importância. Compostos derivados de produtos naturais pode ser uma fonte mais eficaz e econômica para o tratamento desta parasitose. Este estudo avaliou a atividade leishmanicida da espécie Spiranthera odoratíssima (Rutaceae) testando suas frações e isolados in vitro, in vivo e in silico utilizando formas promastigota e amastigota de diferentes espécies de Leishmania em macrófagos J774 A.1. Os ensaios in vitro avaliaram citotoxicidade, produção de óxido nítrico (NO), produção de citocinas interleucina 10, interleucina 12 e IFN-γ. A expressão da proteína quinase p38 ativada por mitógeno (p38 MAPK) e NF-κB (p50 e p65) foi avaliada in vitro por western blotting. Os resultados observados in vitro da fração hexânica do fruto (Fhf) e seu alcaloide isolado esquimianina (Skm) demostraram uma significante ação leishmanicida (P<0·001) contra L. braziliensis. Esta ação foi associada ao aumento da produção de óxido nítrico e diminuição de IL-10 em macrófagos assim como aumento da produção de citocinas Th1 como Il-12 e IFNγ para as concentrações estabelecidas entre 1.6 a 40 μg/ml. Fhf e Skm demostraram induzir a expressão de p38 e NFκB, vias estas envolvidas na produção de citocinas Th1 e na indução de óxido nítrico. Os ensaios in vivo demostraram reduzir lesão em camundongos Swiss infectados com L. braziliensis, assim como foi reduzido à carga parasitária em linfonodos e baço destes animais. O ensaio in silico demonstrou interação significativa entre Skm e resíduos de aminoácidos de NOS-II. Estes resultados em conjunto sugerem que o alcaloide esquimianina é um candidato promissor contra L. braziliensis devido sua potente atividade imunomoduladora.

Made available in DSpace on 2014-07-29T15:16:36Z (GMT). No. of bitstreams: 1 Dissertacao Flavia de Castro Pereira UFG 2010 - part 1.pdf: 495954 bytes, checksum: 284a68ffbde993ede09791444dec1865 (MD5) Previous issue date: 2010-01-22 / Despite the resounding success of cisplatin and closely related platinum antitumor agents, the movement of other transition-metal antitumor agents toward the clinic has been exceptionally slow. Non-Platinum chemotherapeutic metallopharmaceuticals hold much promise for the future, and needs to be actively explored in a large variety of tumor types in combination therapies. The preparations of metallocomplexes with potential antitumor activity has been one of the main targets of transition metal chemistry since Rosenberg s discovery of cisplatin cisdiamminedichloridoplatinum (II), cis-[Pt(NH3)2Cl2]} cytotoxic activity in the 1960s. In 1978, cisplatin was approved as the first platinumbased drug for the oncology treatment, although several negative side-effects (nephrotoxicity, neurotoxicity, nausea, etc.) had been induced on treated patients. Nevertheless, cisplatin was followed by carboplatin {cis-diammine-1,1´ - yclobutanedicarboxylateplatinum(II), [Pt(NH3)2(cbdc)], approved in 1985} and oxaliplatin 1R,2Rdiamminocyclohexaneoxalatoplatinum(II), [Pt(dach)(ox)], approved in 1996}, which met requirements of improving antitumor activity and reducing disadvantages of cisplatin, carboplatin and oxaliplatin represent the second, and third platinum-based drug generations, respectively. Nowadays, not only platinum-bearing complexes are extensively studied with the aim to broaden a spectrum of transition metal-based complexes which could be used in the treatment of cancer. Ruthenium complexes have shown potential utility in chemotherapy and photodynamic therapy. Ruthenium complexes generally have lower toxicities compared to cisplatin attributed to their specific accumulation in cancer tissues. In vitro and in vivo studies show high anticancer activity of Ruthenium complexes and some of them are currently undergoing clinical trials. In the present work we studied the antitumor activity of the Ruthenium(III) compound cis-Tetraammine(oxalato)Ruthenium(III) Dithionate {cis- [Ru(C2O4)(NH3)4]2(S2O6)} against different tumor and normal cells lineages, analising cell viabilities, cell cycle distribution, apoptosis induction mecanistics and genome DNA damage. Correlation tests were performed to determine the effects of the time of exposure and concentration of Ruthenium complex on mitotic index (MI) and mitotic aberration index on Allium cepa root cells. A comparison of MI results of cis- [Ru(C2O4)(NH3)4]2(S2O6) to those of lead nitrate reveals that the Ruthenium complex demonstrates an average mitotic inhibition eightfold higher than lead, with the frequency of cellular abnormalities almost fourfold lower and mitotic aberration threefold lower. A. cepa root cells exposed to a range of Ruthenium complex concentrations did not display significant clastogenic effects. The cis- Tetraammine(oxalato)Ruthenium(III) Dithionate therefore exhibits a remarkable capacity to inhibit mitosis, perhaps by inhibiting DNA synthesis or blocking the cell cycle in the G2 phase. Results showed that Ruthenium(III) causes a significant reduction of proliferation of A549 cells with viabilities ranging from 55.5% to 24.6% when treated with 40 &#956;M for 24 and 48h; and 32% to 18.2% when treated with 150 &#956;M for 24 and 48h. The Ruthenium(III) compound induced a moderate (31.9% and 39.6% for concentrations 10 and 40 &#956;M, respectively) to high degree (74% for concentration 32 &#956;M) of cytotoxic activity against A549 cells (IC50= 33.72 &#956;M). On the other hand, the normal lung fibroblast MRC-5 did not show significant reduction proliferation in the presence of Ruthenium(III) compound. Even when treated with higher concentrations of cis-Tetraammine(oxalato)Ruthenium(III) Dithionate for 48 hours, MRC-5 cells showed viabilities ranging from 85% to 78,4% for 40 &#956;M and 150 &#956;M, respectively. The antiproliferative and cytotoxic activity revealed that K562 cells cultured with concentrations 40 and 150 &#956;g mL-1 of Ruthenium(III) compound showed significant reduction of proliferation after 72h of exposition, with viabilities ranging from 88.2% to 55.6% when treated with 40 &#956;M for 24 and 72h; and 76.2% to 26.7% when treated with 150 &#956;M for 24 and 72h. The Ruthenium(III) compound induced low [22.4% (24h) to 28.2% (48h) and 29.8% (24h) to 35.7% (48h) for concentrations 10 and 40 &#956;M, respectively] to moderate [44% (24h) and 53% (48h) for concentration 150 &#956;M] of cytotoxic activity against K562. After incubation for 48 h, the IC50 value was 18.28 &#956;M. Compared to the cell cycle profiles of untreated cells, flow cytometric analysis indicated a sub-G1 arresting effect of Ruthenium compound on K562 cells, inducing a 1.7-fold, 2.2-fold and 2.4-fold increase in the number of sub-G1 cells for 24, 48 and 72 h, respectively, when compared to control. The compound also caused a significant increase in tailed cells in any of the concentrations tested compared with negative control that can be associated cytotoxicity with direct effect on K562 cells DNA. / Apesar do sucesso da cisplatina e dos medicamentos à base de platina, o mercado de fármacos ainda é acessível para novas drogas á base de metal que oferecem uma melhor viabilidade, tais como a administração oral, o que pode ajudar a diminuir os efeitos colaterais graves e custos clínicos. Além disso, novos estudos concentram-se na investigação de novas drogas com maior eficácia, ou seja, drogas que interajam de forma diferente com o DNA, o que pode levar à superação da resistência inata ou adquirida de certos tipos de tumores. Dentre os vários complexos a base de metais desenvolvidos, os complexos de rutênio (III) representam uma nova família de promissores agentes anticâncer. No presente estudo foi investigado in vitro o efeito do composto Ditionato de cis- Tetraamino(oxalato)rutênio(III) sobre a viabilidade celular, distribuição das fases do ciclo celular, mecanismos de indução de apoptose e danos a molécula de DNA. Os resultados provenientes da análise do teste Allium cepa mostraram um efeito tempo dose-dependente. A avaliação mostrou que a concentração de rutênio teve um impacto maior do que o tempo de exposição. O efeito também se mostrou cumulativo, com uma quase completa inibição da mitose em uma concentração de rutênio de 0,1 mg mL-1 ou superior por períodos superiores a 24 h. Por outro lado, os resultados não revelaram efeitos clastogênicos significativos nas células meristemáticas expostas ao complexo de rutênio (III). A comparação entre os valores dos Índice Mitótico de células meristemáticas de cebolas tratadas com o complexo de rutênio em relação às células tratadas com nitrato de chumbo também mostrou que o complexo de rutênio induziu uma inibição mitótica média oito vezes maior do que o chumbo. Notadamente, as freqüências de anomalias e aberrações celulares mitóticas foram quase quatro vezes e três vezes menores, respectivamente. Os resultados mostram que o composto estudado causa significativa redução da proliferação das células A549 com viabilidades entre 55,5% para 24,6% quando tratados com 40 &#956;M por 24 e 48h; e 32% para 18,2% quando tratados com 150 &#956;M por 24 e 48h. O composto de rutênio(III) induz moderada (31,9% e 39,6% para concentrações 10 e 40 &#956;M, respectivamente) para alta degradação (74% para a concentração 150 &#956;M) para avaliação da atividade citotóxica das células A549 (IC50= 33,72 &#956;M). Quanto à linhagem de fibroblasto de pulmão humano normal MRC-5, não mostrou redução significativa na proliferação celular na presença do composto. Quando tratadas com altas concentrações do Ditionato cis-Tetraamino(oxalato)rutênio(III) por 48 horas, celulas MRC-5 mostraram viabilidades altas de 85% e 78,4% para 40 &#956;M e 150 &#956;M, respectivamente. A atividade citotóxica e antiproliferativa revelou que a cultura de células K562 nas concentrações de 40 e 150 &#956;g mL-1 do composto de Rutênio(III) mostrou redução significativa na proliferação 72h de exposição, com viabilidades de 88,2% para 55,6% quando tratadas com 40 &#956;M por 24 e 72h; e 76,2% para 26,7% quando tratadas com 150 &#956;M por 24 e 72h. O composto de Rutênio(III) induziu baixa [22,4% (24h) para 28,2% (48h) e 29,8% (24h) para 35,7% (48h) para concentrações de 10 e 40 &#956;M, respectivamente] para moderada [44% (24h) e 53% (48h) para concentrações de 150 &#956;M] atividade citotóxica em células K562. Após a incubação de 48 h, o valor da IC50 foi de 18,28 &#956;M. Quando comparado o ciclo celular de células não tratadas, a análise indica que as células foram arrastadas para sub-G1 apresentando um aumento de 1,7 para 2,2 e 2.4% no número de células em sub-G1 por 24, 48 e 72 h, respectivamente, quando comparado com o grupo controle. O composto também causou um significativo aumento em danos celulares nas concentrações testadas quando comparado com o controle negativo, o que pode estar associado com efeitos citotóxicos diretamente no DNA celular.