Submitted by Verena Bastos (verena@uefs.br) on 2015-08-05T22:08:06Z No. of bitstreams: 1 Disserta??o Mona Oliveira vers?o final Maio2003 PPGbiotec.pdf: 4793209 bytes, checksum: 5e62150796f4527c8d492f92de5041e2 (MD5) / Made available in DSpace on 2015-08-05T22:08:06Z (GMT). No. of bitstreams: 1 Disserta??o Mona Oliveira vers?o final Maio2003 PPGbiotec.pdf: 4793209 bytes, checksum: 5e62150796f4527c8d492f92de5041e2 (MD5) Previous issue date: 2013-05-08 / Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB / Glioblastomas (GBMs) are the most common and aggressive primary tumors of the CNS. The survival of patients with this diagnosis remains very low, with poor prognosis even after surgical therapy associated with radiotherapy and chemotherapy. The present work carried out a screening for 24 synthetic ?alkaloid-like? to determine their effects on cell viability of quimioresistentes human (Gl-15 and U251) glioblastoma cells and murine (C6) glioma cells. Among the alkaloids tested (100?M) RLB87 was the most cytotoxic for transformed cells, inhibiting the viability in 75.0% 97.2% 76.6% of GL-15, U251 and C6 cells, respectively, after 72 h exposure, and it did not show toxicity to normal glial cells. It was also observed that RLB87 promoted apoptosis, 24 and 72 h after treatment, in a time-dependent manner. Moreover RLB87 also inhibited cell migration and proliferation with cells arrest at G0/G1 phase, since 24 h after treatment. Additionally, the cytotoxicity of four RLB87 analogues was tested in view to elucidate important aspects in chemical structure, required for its activity. We observed positive correlation between cytotoxic effect and isomeric of phenyl functions, with ester function and also lipophilicity. These finding suggest the ?alkaloid-like? RLB87 as a promising anticancer agent as well as a prototype for new agents for treatment of malignant and recurrent gliomas. / Glioblastomas (GBMs) s?o os tumores prim?rios mais comuns e agressivos do SNC. A sobrevida dos pacientes com esse diagn?stico continua muito baixa, tendo progn?stico ruim mesmo ap?s terapia cir?rgica seguida de radio e quimioterapia. No presente trabalho, foi realizada a prospec??o de 24 mol?culas de s?ntese, alkaloids-like, para determina??o de seus efeitos sobre a viabilidade de c?lulas quimioresistentes de glioblastoma humano (GL-15 e U251) e murina (C6). Entre os compostos testados ? (100JM), RLB87 foi o mais citot?xico para c?lulas transformadas, inibindo a viabilidade em 75,0%, 97,2%, 76,6% da GL-15, U251 e C6, respectivamente e o mesmo n?o apresentou toxicidade para c?lulas gliais normais. Observou-se, que o RLB87 promoveu apoptose 24 e 72 h ap?s o tratamento de forma tempo-dependente. O RLB87 igualmente inibiu a prolifera??o celular com acumulo na fase G0/G1 do ciclo celular ap?s 24 h. A migra??o das c?lulas de glioma foi tamb?m inibida ap?s tratamento com RLB87. Adicionalmente 4 an?logos do RLB87 foram tamb?m avaliados, elucidando aspectos importantes na estrutura qu?mica, requeridos para sua atividade, que possuem correla??o positiva com regioisomeria das fenilas, presen?a da fun??o ?ster e lipofilicidade. O RLB87 ? apresentado como promissor agente antineopl?sico assim como um prot?tipo para novos agentes terap?uticos para o tratamento de gliomas malignos e recidivados.

Desde a descoberta da cisplatina várias tentativas têm sido feitas com o objetivo de desenvolver novos quimioterápicos com menor toxicidade e efeitos colaterais melhorados para tratar o câncer. Complexos de coordenação com metais de transição variados vêm sendo estudados buscando melhoras na biodisponibilidade, seletividade e efeitos adversos. Neste sentido, o presente trabalho consiste na síntese e caracterização estrutural de complexos de PdII e PtII com ligantes derivados de tiossemicarbazidas contendo o grupo fluoróforo pireno visando a obtenção de potenciais agentes antitumorais. Os agentes quelantes foram preparados a partir de reações de condensação entre o pirenocarboxaldeído e a tiossemicarbazida desejada resultando em compostos 1-pirenocarboxaldeído-N(3)-R-tiossemicarbazona, H2PrR, onde R = etil ou ciclohexil, Pr = pireno. A partir dos ligantes H2PrR foram realizadas as reações de complexação com os íons metálicos PdII e PtII, sendo possível obter duas classes de complexos com diferentes características: complexos monoméricos contendo ligantes clorido e trifenilfosfano do tipo [MCl(PPh3)(HPrR)] e complexos tetraméricos do tipo [M4(μ-S-PrR-κ3-C,N,S)4], onde M = PdII ou PtII, R = etil ou ciclohexil. Nas duas primeiras séries, o grupo R foi modificado por etil e ciclohexil para investigar a correlação entre lipoficilidade e atividade antiproliferativa, enquanto que o grupamento pireno foi incluído pensando que um maior número de unidades aromáticas possivelmente melhoraria a intercalação com o DNA e/ou ser utilizado como um marcador celular. A caracterização dos complexos envolveu técnicas como: análise elementar, espectroscopia na região do infravermelho e do UV-Vis, condutimetria, ressonância magnética nuclear (1H e 13C RMN) e difração de raios X em monocristal. As análises mostraram que os agentes complexantes podem atuar em diferentes modos coordenação tanto com relação à denticidade quanto à carga. A atividade antiproliferativa dos novos compostos de PdII e PtII foi determinada, sendo que vários deles apresentaram IC50 promissores contra células de câncer de ovário e, em muitos casos, as atividades observadas foram melhores do que a da cisplatina. Os dados obtidos indicam efeitos diferentes nos resultados de atividade biológica para os centros metálicos (Pd vs Pt) e ligantes utilizados (Etil vs Ciclohexil). Estudos de captação e distribuição celular mostraram que o complexo [PdCl(PPh3)(HPrCh)] atinge o núcleo celular. Com o intuito de verificar possíveis alvos biológicos, testes de interação com o DNA, ciclo celular e inibição da enzima Top IB foram realizados para os compostos. Os resultados do ciclo celular, mostraram uma maior inibição nos estádios S e G2/M para os complexos do tipo [PdCl(PPh3)(HPrR)]. Diante dos resultados obtidos, verificou-se que a Top IB é um dos alvos moleculares para os complexos do tipo [MCl(PPh3)(HPrR)], um mecanismo diferente da cisplatina. Estes resultados preliminares são bastante promissores e mostram que alguns dos complexos estudados neste trabalho apresentam-se como potenciais agentes para serem usados na terapia do câncer em combinação com os demais fármacos em uso clínico. / Since the discovery of cisplatin, many attepemts have been made to prepare new drugs with less cytotoxicity and side effects. Coordination complexes based on a variety of transition metals have been developed in the search for improved bioavailability, selectivity and reduced adverse side-effects. This work consists on the synthesis and structural characterization of PdII and PtII complexes with chelating compounds derived from thiosemicarbazides containing the pyrene fluorophore group aiming to obtain potential antitumor compounds. The chelating agents were prepared from condensation reactions between the pyrenocarboxaldehyde and the desired thiosemicarbazide resulting in 1-pyrenocarboxaldehyde-N (3) -R-thiosemicarbazone compounds, H2PrR, where R = ethyl or cyclohexyl. Complexation reactions with the metal ions PdII and PtII were carried out with the H2PrR ligands. It was possible to obtain two main classes of complexes with different characteristics: i) monomeric complexes containing chlorido and triphenylphosphane ligands of the type [MCl(PPh3)(HPrR)] and (ii) tetramer complexes of the type [{M(PrR)}4], where M = PdII or PtII and R = etyl ou cyclohexyl. In both series the R group was modified by ethyl and cyclohexyl in order to investigate the correlation between lipophilicity and antiproliferative activity, while the pyrene group was attached to the ligands with the belief that a higher number of aromatic units would improve DNA intercalation and/or to be used as an intracellular probe. The characterization of the complexes involved techniques such as: elemental analysis, infrared and UV-Vis spectroscopy, conductimetry, nuclear magnetic resonance (1H and 13C NMR) and single crystal X-ray diffraction. The antiproliferative activity of the novel PdII and PtII compounds have been determined, several of them showed promising IC50 against ovarian cancer cells, and in many cases the observed activities are better than that of cisplatin. The data obtained indicate different effects for the metal centers (Pd vs Pt) and the ligands used (ethyl vs cyclohexyl). Uptake and cellular distribution studies proved that the palladium complex [PdCl(PPh3)(HPrCh)] achieved the cell nucleus. In order to verify possible biological targets, interaction with DNA, cell cycle and inhibition experiments of the topoisomerase IB (Top IB) enzyme were performed for some compounds. Cell cycle results showed an inhibition at the S and G2/M stages for the complexes [PdCl(PPh3)(HPrR)]. Overall, the results indicated the Top IB enzyme as one of the targets of the complexes. These preliminary results are quite promising and show that some of the complexes studied here can be used in cancer therapy in combination with other anticancer drugs.

Os ensaios celulares têm ganhado relevância na gênese planejada de fármacos, devido a sua utilização nas diversas etapas envolvidas neste processo. Estes ensaios envolvem a caracterização da atividade farmacológica, propriedades farmacocinéticas e atividade tóxica para compreender a atividade biológica das moléculas de interesse. Neste trabalho, os ensaios celulares foram usados para identificar a atividade anticancerígena e a atividade tóxica de moléculas, uma vez que a morte celular é o parâmetro avaliado em ambos os casos. No presente estudo foram avaliados 34 compostos, sendo dezessete moléculas do grupo NEQUIMED, determinando-se sua atividade citotóxica na célula neoplásica de fígado (HepG2) e na célula de fibroblasto (V79-4). A determinação da atividade citotóxica dos compostos bioativos foi realizada por o método colorimétrico de triagem envolvendo o MTT (brometo de 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazólio), que é metabolizado pela mitocôndria da célula viva, com confirmação da atividade biológica realizada por citometria de fluxo para a linhagem de fibroblasto. As triagens iniciais foram estabelecidas para determinar a atividade biológica, sendo que as moléculas Neq256, Neq385 e Neq388 apresentaram atividade citotóxica frente à célula HepG2 (caracterizando assim a atividade anticancerígena), enquanto que Neq385 apresentou seletividade em relação a atividade nas células de fibroblasto. Dentre as moléculas de referência, YM-155 apresentou os melhores resultados de atividade citotóxica com IC50 (HepG2) de 0,094 µmol L-1 e IC50 (V79-4) > 100 µmol L-1, sendo muito seletiva para a linhagem cancerígena. Os resultados demonstraram que as moléculas Neq265, Neq385 e Neq388 são promissoras e serão usadas para o planejamento de modificações estruturais que visa obter moléculas com maior potência e seletividade frente às células cancerígenas. Outra vertente do trabalho envolve o planejamento de inibidores da survivina, que apresentam grande potencial para a descoberta e desenvolvimento de estratégias quimioterápicas seletivas. / Cell-based assays are gaining relevance in the drug discovery and development area, being in use almost throughout the whole process. These assays are applied to characterize the pharmacological, pharmacokinetic and toxic activities of new molecules. In this work, cell-based assays were performed to identify anticancer and toxic activities of novel compounds, once the cell death process is the parameter that was evaluated in both cases. In this work, 34 compounds were evaluated (17 of them from the NEQUIMED database) in which the cytotoxic activity in liver cancer cells (HepG2) and hamster fibroblast cells (V79-4) were determined by means of the MTT colorimetric screening. The biological activity in fibroblast cells was further confirmed by using flow cytometry. Out of the whole set, molecules Neq256, Neq385 e Neq388 were cytotoxic to HepG2 (having anticancer activity). Neq385 was selective towards the liver hepatocellular carcinoma when compared with the fibroblasts. Among the reference compounds, YM-155 was the most selective and potent anticancer molecule: IC50 (HepG2) 0.094 µmol L-1 and IC50 (V79-4) > 100 µmol L-1. Taken together, these results provide promissing new molecules (Neq265, Neq385 e Neq388) for further optimization of the potency and selectivity using drug design. Another important outcome for further exploration is the design of survivin inhibitors bearing a huge potential for novel selective chemotherapeutic approaches.

Commiphora species (from which myrrh is obtained) has been a source of several novel and bio-active natural compounds. Traditionally, Commiphora (Burseraceae) is used in southern Africa for the treatment of ulcers, fevers, and as a remedy for snake and scorpion bites. In western Africa, the macerated stem is used in the treatment of rheumatic conditions. The resin of some Commiphora species is applied topically to aid in wound healing. Documented uses include antibacterial and antifungal properties, as well as cytotoxic, cytostatic and anti-oxidant activity. The botanical diversity of this genus in South Africa warrants a study of this plant group, to provide scientific evidence for the traditional use of Commiphora species in African healing rites. Ten Commiphora species were investigated. Fresh plant material of the selected species were identified and collected from natural populations in the Limpopo Province. Active compounds, viz. kaempferol and dihydrokaempferol, in C. glandulosa (stem) were isolated using bioassay-guided fractionation and identified using nuclear magnetic resonance spectroscopy. The stem and leaf extracts of each species were analysed for in vitro anti-oxidant, antimicrobial, anti-inflammatory, anticancer activity, as well as cytotoxicity. The anti-oxidant activity of the extracts was investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the 2,2’-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) (ABTS) assays. Extracts generally exhibited poor anti-oxidant activity in the DPPH assay, with the exception of C. schimperi (stem), C. neglecta (stem), C. tenuipetiolata (stem and leaf), and C. edulis (stem), which possessed IC50 values ranging between 7.31 μg/ml and 10.81 μg/ml. Isolated compounds were subjected to the DPPH assay to determine the anti-oxidant potential of each compound, separately and in combination to establish possible synergistic, antagonistic or additive effects. The flavonol, kaempferol (IC50 = 3.32 μg/ml) showed exceptional radical scavenging activity, in contrast to the low activity displayed by dihydrokaempferol (IC50 = 301.57 μg/ml), their combination being antagonistic. Greater anti-oxidant activity was observed for most species in the ABTS assay when compared to the results obtained in the DPPH assay. The best activity was observed for the stem extracts of C. neglecta (IC50 = 7.28 μg/ml) and C. mollis (IC50 = 8.82 μg/ml). In vitro antimicrobial efficacy was determined against Gram-positive and Gram-negative bacteria as well as yeasts using the MIC microtiter plate assay. A greater selectivity was exhibited by the extracts against the Gram-positive bacteria and yeast than against the Gram-negative bacteria. Using death kinetics studies (time-kill studies), the rate at which the antimicrobial agent kills pathogens over a 24-hour period was determined. The antibacterial activity of Commiphora marlothii (stem) was observed to begin at ca. 30 min of the exposure of S. aureus to the different concentrations of plant extract. All concentrations exhibited antibacterial activity, with a complete bactericidal effect achieved by all test concentrations by the 24th hour. Commiphora pyracanthoides (stem) displayed anti-inflammatory activity through good inhibition of the 5-LOX enzyme (IC50 = 27.86 μg/ml). The ability of extracts and kaempferol to inhibit the in vitro growth of three human cancer cell lines, namely the colon adenocarcinoma (HT-29), breast adenocarcinoma (MCF-7), and the neuronal glioblastoma (SF-268), was evaluated using the sulforhodamine (SRB) antiproliferative assay. The most active Commiphora species against the HT-29 cells were C. glandulosa (leaf and stem) and C. marlothii (leaf). The MCF-7 cell line was the most sensitive to indigenous Commiphora species, with C. edulis (leaf and stem), C. glandulosa (leaf and stem), C. marlothii (leaf), C. pyracanthoides (leaf and stem), C. schimperi (stem), and C. viminea (stem) all possessing an inhibition greater than 80% at 100 μg/ml. Commiphora glandulosa (leaf and stem) and C. pyracanthoides (leaf and stem) were the two most active species against the SF-268 cells, with IC50 values ranging between 68.50 μg/ml and 71.45 μg/ml. The inhibition of the cancer cell proliferation by kaempferol in all three-cancer cell lines was determined, with IC50 values of 9.78 μg/ml in HT-29 cells, 20.21 μg/ml in MCF-7 cells and 43.83 μg/ml in SF-268 cells. The microculture tetrazolium cellular viability (MTT) assay was used to determine the cellular toxicity of the extracts against transformed human kidney epithelium (Graham) cells. Commiphora glandulosa (stem) proved to be most toxic (IC50 = 30.5 μg/ml). The IC50 values for all other extracts were in excess of 95 μg/ml suggesting low in vitro toxicity for the majority of the species. A phytochemical investigation of the non-volatile constituents of the leaf and stems was conducted using high performance liquid chromatography (HPLC). The HPLC profiles and UV spectra of the stem extracts, and the representative flavonoid patterns in the leaf extracts of the species indicate that a similarity exists in their chemical fingerprint.

Proteomics is the large scale study of proteins in cells or organisms. The purpose of this study was to characterize the proteomic alterations occurring in a prostate cancer (LNCaP) cell line after treatment with delta-tocotrienol (a form of vitamin E not very prevalent from most dietary sources). We found that both gamma- and delta-tocotrienols induced time and concentration dependent growth inhibition and programmed cell dead (apoptosis) in LNCaP cells. Secondly, we used two-dimensional gel electrophoresis (2-DE) to characterize changes in protein expression levels associated with this treatment. Our results show that a specific set of proteins are regulated at both early and late times following treatment with delta-tocotrienol and these proteins have been characterized by their apparent molecular weights and isoelectric points. The alteration observed at early time points are particularly interesting because these changes are likely to reflect the underlying molecular mechanisms for triggering cancer cell death.

This research focused on the cytotoxic properties of RRR-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in transformed and cancerous cell lines. We used RAW264.7 macrophage and prostate cancer (LNCaP) cell lines in this study. TPGS caused cell death and decreased cell viability in a dose and time dependent manner. Cell death was evaluated fluorimetrically by employing the nucleic acid-binding fluorophore; propidium iodide. A colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. Cell death can occur through necrosis or apoptosis. Our results suggested that TPGS triggered apoptotic cell death. Induction of apoptosis, as measured by caspase 3 enzymatic activity, was dependent upon the TPGS dose and incubation time. Caspase 8 was activated before caspase 9, suggesting the importance of the death receptor pathway in apoptosis. Our results indicated that TPGS cytotoxicity could also be due to one of its products of hydrolysis, alpha-tocopheryl succinate.

Faschingbauer J.: Cytotoxic and cholinesterase inhibitory activity of extracts from selected species of the Centaurea L. genus. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové, 2019. During the screening of biologically active secondary metabolites of plants carried out at the Department of Pharmaceutical Botany FAF UK, selected taxa of the genus Centaurea (Asteraceae) were investigated. This study is focused on a basic phytohemical research of extracts prepared from Centaurea cyanus, Centaurea jacea, Centaurea scabiosa, Centaurea pseudophrygia, Centuarea stoebe, Centaurea solstitialis a Centaurea benedicta. Extracts were prepared for evidence of the proof reactions of TLC and MS analysis (EI, ESI) to clarify a potential presence of alkaloids. EtOAc and ethanol extracts were evaluated for potential inhibitory activity against human erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE) and cytotoxicity against selected 9 tumor lines. C. cyanus alkaloid extract had interesting cholinesterase activity which selectively inhibited BChE (IC50 BChE = 22.62 ± 3.62 μg / ml, IC50 AChE = 221.50 ± 44.56 g / ml). Other EtOAc extracts of selected Centaurea species were considered inactive (IC50 > 100 μg/ml)....

Orientador: Cristiane Duque / Coorientador: AiméeMaria Guiotti / Banca: Marcelle Danelon / Banca: Aline Rogéria Freire de Castilho / Resumo: Embora o tratamento endodôntico convencional reduza significativamente a microbiota presente no interior dos canais radiculares, a permanência de microrganismos devido à complexidade anatômica do sistema de canais radiculares e a resistência destes ao tratamento químico-mecânico pode ocasionar infecções persistentes ou secundárias. Muitos estudos têm explorado o uso de fitoquímicos, buscando obter novos compostos que apresentem propriedades farmacológicas. A curcumina, pigmento amarelo isolado dos rizomas da Curcuma longa (Zingiberaceae), e o cinamaldeido, substância volátil responsável pelo odor e sabor das cascas dos caules de plantas do gênero Cinnamomum (Lauraceae) são possíveis substâncias promissoras. O objetivo do estudo foi avaliar o efeito citotóxico e ação antimicrobiana/antibiofilme de compostos híbridos de curcumina e cinamaldeído sobre microrganismos de interesse endodôntico. Foram realizados ensaios para determinação da Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM) do cinamaldeído, da curcumina e dos 23 híbridos sobre Enterococcus faecalis, Streptococcus mutans, Lactobacillus casei, Actinomyces israelii e Fusobacterium nucleatum. Os melhores compostos foram avaliados em ensaios de biofilme simples (cada cepa bacteriana isoladamente) e dual-espécies (E. faecalis + L. casei, E. faecalis + S. mutans, E. faecalis + A. israelii, E. faecalis + F. nucleatum) em placas de poliestireno objetivando-se determinar o efeito sobre o metabolismo ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Although conventional endodontic treatment significantly reduces the microbiota present inside the root canals, the permanence of microorganisms due to the anatomical complexity of the root canal system and their resistance to chemical-mechanical treatment can lead to persistent or secondary infections. Many studies have explored the use of phytochemicals, seeking to obtain new compounds that present pharmacological properties. Curcumin, a yellow pigment isolated from Curcuma longa rhizomes (Zingiberaceae), and cinnamaldehyde, the volatile substance responsible for the odor and taste of plant stems of the genus Cinnamomum (Lauraceae) are possible promising substances. The objective of the study was to evaluate the cytotoxic effect and antimicrobial action / antibiofilm of hybrid compounds of curcumin and cinnamaldehyde on microorganisms of endodontic interest. The minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBM) of cinnamaldehyde, curcumin and 23 hybrids on Enterococcus faecalis, Streptococcus mutans, Lactobacillus casei, Actinomyces israelii and Fusobacterium nucleatum were determined. The best compounds were evaluated on single biofilms (single bacterial strain) and dual-species biofilms (E. faecalis + L. casei, E. faecalis + S. mutans, E. faecalis + A. israelii, E. faecalis + F. nucleatum) in polystyrene plates to determine the effect on bacterial metabolism using the XTT assay and its viability by counting Colony Forming Units (CFUs) after ... (Complete abstract click electronic access below) / Mestre

Le présent travail rend compte des études phytochimiques et biologiques d'extraits non volatils de quatre plantes utilisées au Bénin dans le traitement du diabète. La première partie passe en revue la bibliographie sur les plantes sujettes à notre étude. Dans cette partie, la systématique, l'importance en pharmacopée ainsi que les travaux déjà effectués sur ces plantes ont été présentés. La deuxième partie présente le mode d'extraction et les études chimiques des extraits et les résultats obtenus. La spectrophotométrie a permis de déterminer quelques grandes familles de composés présents dans les extraits : les polyphénols totaux, les flavonoïdes et les tanins tandis que la GC/MS et la LC/MS ont servi à mettre en exergue la présence de composés volatils et non volatils. La troisième partie décrit les tests biologiques in vitro et ex vitro effectués sur les extraits. Les extraits ont montré de manière générale des activités : inhibitrice de l' α-glucosidase, antioxydantes (DPPH, FRAP, ORAC), antimicrobiennes et l'une (Bridelia ferruginea) une activité cytotoxique sur les cellules cancéreuses (PA1, MCF7, PC3, DU-145), avec une efficacité variable d'une plante à une autre. La quatrième partie discute de manière générale des résultats issus des études phytochimiques et des tests biologiques. Parmi les quatre échantillons de plantes sélectionnées pour notre étude, seul l'extrait semi-éthanolique des racines de Ceiba pentandra a une faible teneur en familles de composés dosés et présente des activités biologiques (ci-dessus citées) faibles comparativement aux extraits de Bridelia ferruginea, de Pseudocedrela kotschyi et de Polygonum senegalensis. L'ensemble des résultats tant sur le plan chimique que biologique met en évidence les potentialités des extraits de plantes étudiées, pour une exploitation à des fins thérapeutiquesfutures. / The present work had reported on the phytochemical and biological studies of non-volatile extracts of four plants used in Benin for diabetes treatment. The first part reviewed the bibliography of investigated plants in our study. In this part, the systematic, the importance in the pharmacopoeia and the previous works done on these plants were presented. The second part has presented the extraction method and chemical studies of the extracts and results obtained. The spectrophotometry has permitted to identify some important families of compounds in the extracts: the total polyphenols, flavonoids and tannins whereas the GC / MS and LC/MS were used to highlight the presence of volatile and non-volatile compounds. The third part described the biological tests in vitro and ex vitro carried out on the extracts. The extracts showed in general activities: α-glucosidase inhibition, antioxidant (DPPH, FRAP, ORAC), antimicrobial, and one of them (Bridelia ferruginea) were cytotoxic on cancer cells (PA1, MCF7, PC3, DU-145), with a variable efficiency from one plant to another. The fourth part had discussed in general about the results obtained from phytochemical studies and biological tests. Among the four plants samples selected for our study, only the semi-alcoholic extract of Ceiba pentandra roots had a low-dosed compounds families and presented of this biological activities (cited below) low comparatively to Bridelia ferruginea, Pseudocedrela kotschyi and Polygonum senegalensis extracts. Both of the chemical and biological results highlight the potential of certain species for future exploitation of their non-volatile extract for therapeutic purposes.

<p>The development of resistance by tumour cells to chemotherapeutic agents is a major problem in cancer treatments. One way to counter this is to find compounds with cytotoxic mechanisms other than those of drugs in clinical use today. The biological and chemical diversity encountered in Nature provide opportunities to discover completely new chemical classes of compounds. Some of these may represent previously unknown anticancer agents, and in some cases, novel, potentially relevant cytotoxic mechanisms. </p><p>The selection of plants for the cytotoxic investigation in this project was designed to cover large parts of the angiosperm system, providing a broad representation of species. Extracts of the plants were subjected to a polypeptide fractionation protocol, followed by bioassay-guided isolation, yielding series of fractions with increasing purity and cytotoxicity. The cytotoxicity assay included tumour cells from patients and a cell-line panel including ten different cell lines representing several types of resistant and non-resistant tumours. This screening strategy allowed fractions and compounds acting with novel mechanisms to be detected at an early stage. </p><p>The compounds isolated represent substantial chemical diversity and originate from diverse parts of the phylogenetic spectrum examined. They include the highly potent cytotoxic alkaloid, thiobinupharidine, the structure of which was determined by NMR techniques. Furthermore, two types of compound were shown to have previously unreported cytoxic activity: cyclotides (small macrocyclic polypeptides, in this case from violets) and polypeptides, possibly of thionine type, of loranthaceaeous mistletoes (collected in Panama). The well known cardiac glycosides from the foxglove, Digitalis, were identified as being responsible for the anti-tumour activity of this species.</p><p>In conclusion, the results obtained in this project show that selection based on phylogenetic information, together with a robust and reliable method to detect cytotoxicity, can be a useful approach for exploring the plant kingdom for cytotoxic substances.</p>