As part of an International Cooperative Biodiversity Group (ICBG) program and a collaborative research project with the Natural Products Discovery Institute, twenty plant extracts were investigated for their antiproliferative and antimalarial activities. Bioassay guided fractionation of thirteen extracts led to the identification of three new antiproliferative compounds, ethyl leptaulosides A-C (5.1-5.3), six new antiplasmodial compounds, apoplanesiacarpan A and B (2.4-2.5), (±)-rhodomyrtosone F (3.1), (±)-calliviminone C (3.2), 3α-angeloyloxy-15-hydroxylabda-7,13-dien-16,15-olid-18-oic acid (4.1), 3α-angeloyloxy-15-methoxylabda-7,13-dien-16,15-olid-18-oic acid (4.2), and twenty-six known compounds. The structures of these compounds were elucidated by using a combination of 1D (1H and 13C) and 2D NMR spectroscopy, mass spectrometry, UV, IR, CD, optical rotation, and chemical modifications. Compounds 5.1 and 5.2 showed moderate antiproliferative activity against the A2780 human ovarian cancer cell line assay with IC50 values of 3 uM and 10 uM, respectively. Compound 3.1 showed potent antiplasmodial activity with an IC50 value of 100 nM, while compounds 3.2 and 4.1 showed moderate antiplasmodial activity with IC50 values of 4 uM and 10 uM, respectively. The other compounds had IC50 values larger than 20 ug/mL, and were thus either inactive or only weakly active. / Ph. D. / Plant based natural products have a long history of being used for medicinal purposes and have played an important role in the modern drug discovery program, with the best known examples being paclitaxel as an anticancer drug, and quinine and artemisinin as antimalarial drugs. Despite great progress in fighting malarial and cancer, both diseases remain difficult to combat due to emergence of drug resistance in malarial parasites and hardness to treat various types of cancer. Therefore, it is urgent to discover new antimalarial and anticancer agents to treat these deadly diseases. This research focuses on identifying new antimalarial and anticancer agents from plant extracts. Investigation of twenty plant extracts led to the isolation of three new anticancer, six new antimalarial and twenty-six known compounds. The isolation and structure elucidation of these new bioactive compounds will be discussed in this dissertation.

No description available.

As part of an International Cooperative Biodiversity Groups (ICBG) program and a continuing search for anticancer natural products from the Madagascar rainforest, twenty extracts from Madagascar were selected for investigation based on their antiproliferative activity. Bioassay-guided fractionation of five of the extracts yielded sixteen new compounds, and their structures were determined using a combination of 1D and 2D NMR experiments, including COSY, HSQC/HMQC, HMBC, and ROESY/NOESY sequences, mass spectrometry, and chemical conversion. In addition, ten known compounds were obtained from five of the extracts. Studies on the remaining extracts were suspended due to various reasons. A multi-step synthesis of the sesquiterpenoid, (7R*)-opposite-4(15)-ene-1beta,7-diol, was also described. The first chapter of this dissertation reviews the new compounds isolated from Malagasy plants and marine organism in the last two decades. Chapters II to VI discuss the isolation, structure elucidation and bioactivities of new compounds from Scutia myrtina, Cordyla madagascariensis ssp. madagascariensis, Elaeodendron alluaudianum, Cassipourea lanceolata, and Sclerocarya birrea subsp. caffra. Chapter VII describes the synthesis and bioactivity of the sesquiterpenoid,(7R*)-opposite-4(15)-ene-1beta,7-diol. The isolation of known compounds is discussed briefly in the last chapter. / Ph. D.

The natural product, paclitaxel, has made tremendous contributions in supplying the arsenal of anticancer therapeutics, and was FDA approved for clinical use in 1992. In order to design simplified analogs, the conformation that paclitaxel adopts when binding to tubulin has been the subject of ongoing studies. Much evidence has led to a T-taxol proposal and a C3' constrained analog has been designed and synthesized as a test of this conformation. In the search for more active analogs, a number of modifications have been made to paclitaxel by other researchers. However, the nature of the alterations, and combinations thereof, have not been exhausted. To this end, synthesis of northern hemisphere B-ring analogs is underway. / Master of Science

Devido ao grande avanço na descoberta de novos fármacos a partir de compostos naturais, tornou-se interessante avaliar o potencial antiproliferativo de moléculas isoladas de extratos de plantas. Este trabalho prioriza o estudo da atividade antitumoral de benzofenonas (carifenona A e carifenona B) e floroglucionóis (japonicina A e uliginosina B), isolados das espécies nativas do sul do Brasil, Hypericum carinatum e Hypericum myrianthum, respectivamente, bem como a associação destes com quimioterápicos utilizados na clínica. Os experimentos propostos foram realizados em modelos in vitro, utilizando diferentes tipos de linhagens tumorais humanas comercialmente disponíveis. Foi avaliado o efeito de diferentes doses destes compostos através de experimentos de viabilidade e sobrevivência celular, análise morfométrica nuclear (NMA) e citometria de fluxo. Na análise estatística foi utilizada a variância de uma via (ANOVA) seguida de teste post-hoc (Tukey). Os resultados foram expressos como média ± erro padrão da média (SEM), sendo valores de P menores do que 0,05 considerados significativos. Verificamos que nas linhagens de adenocarcinoma de ovário e colorretal e de glioblastoma (OVCAR-3, HT-29 e U-251) ocorreu uma diminuição significativa na viabilidade celular quando tratadas com a dose de 100μg/mL tanto de carifenona A como de carifenona B, enquanto os compostos japonicina A (50μg/mL) e uliginosina B (20μg/mL) só foram ativos na linhagem OVCAR-3. Dentre as associações com quimioterápicos, a única que apresentou efeito sinérgico foi a combinação de japonicina A e paclitaxel na linhagem OVCAR-3. A partir deste momento selecionamos a japoncina A para dar continuidade aos estudos. Este composto foi avaliado frente a outros tipos de linhagens tumorais, sendo ativa somente em células de adenocarcinoma de ovário e próstata (OVCAR-3 e PC-3). Na linhagem PC-3, a análise do ciclo celular demonstrou decréscimo da fase G1 e indução ao arraste da fase G2, assim como, através da técnica de NMA, foi verificado um aumento de células apoptóticas, quando as células foram tratadas com japonicina A. Estudos moleculares devem ser realizados para melhor entendimento do mecanismo de ação da japonicina A, composto que pode servir de modelo para o desenho de fármacos mais específicos para este tipo de neoplasia. / Due to the great progress in the discovery of new drugs from natural compounds, it has become interesting to evaluate the antiproliferative activity of molecules isolated from plant extracts. This work emphasizes the study of antitumor activity of benzophenones (cariphenone A and cariphenone B) and phloroglucionols (japonicin A and uliginosin B), isolated from Hypericum species native to southern Brazil, H. carinatum and H. myrianthum, respectively, as well as their association with chemotherapeutic drugs used in the clinic. The proposed experiments were performed in vitro using commercially available cell lines. The effect of different doses of these compounds were evaluated via cell viability and survival assay, nuclear morphometric analysis (NMA) and flow cytometry. One way analysis of variance (ANOVA) followed by post hoc tests (Tukey) were utilized for statistical analysis. Results were expressed as mean ± standard error of the mean (SEM), and P values less than 0.05 were considered significant. We found that in ovarian, colorectal (adenocarcinoma) and glioblastoma cell lines (OVCAR-3, HT-29 and U-251) a significant decrease in cell viability occurred when these were treated with a dose of 100μg/mL of cariphenone A and B, while compounds japonicin A (50μg/mL) and uliginosin B (20μg/mL) were active only in OVCAR- 3. Among the associations with chemotherapeutic agents, only japonicin A presented a synergistic effect with paclitaxel in the OVCAR-3 cell line. We then selected japonicin A for evaluation against other cell lines, but its effects were only observed in ovary and prostate adenocarcinoma cell lines (OVCAR-3 e PC-3). In PC-3, the cell cycle revealed a decreased in the G1 phase and induction of G2 arrest, the NMA showed an increase in apoptotic cells when cells were treated with japonicin A. More studies should be conducted to better understand the mechanisms of action of japonicin A, since this compound may serve as pharmacophore model for the design of more specific drugs to treat this tumor type.

The trioxacarcins are structurally complex, highly oxygenated bacterial isolates that potently inhibit the growth of human cancer cells in culture as a consequence of their ability to alkylate guanosine residues of duplex DNA. This dissertation presents a component-based synthetic route to the trioxacarcin structural class, broadly defined, which resulted in fully synthetic routes to trioxacarcin A (1), DC-45-A1 (10), and a diverse collection of analogs. / Chemistry and Chemical Biology

Devido ao grande avanço na descoberta de novos fármacos a partir de compostos naturais, tornou-se interessante avaliar o potencial antiproliferativo de moléculas isoladas de extratos de plantas. Este trabalho prioriza o estudo da atividade antitumoral de benzofenonas (carifenona A e carifenona B) e floroglucionóis (japonicina A e uliginosina B), isolados das espécies nativas do sul do Brasil, Hypericum carinatum e Hypericum myrianthum, respectivamente, bem como a associação destes com quimioterápicos utilizados na clínica. Os experimentos propostos foram realizados em modelos in vitro, utilizando diferentes tipos de linhagens tumorais humanas comercialmente disponíveis. Foi avaliado o efeito de diferentes doses destes compostos através de experimentos de viabilidade e sobrevivência celular, análise morfométrica nuclear (NMA) e citometria de fluxo. Na análise estatística foi utilizada a variância de uma via (ANOVA) seguida de teste post-hoc (Tukey). Os resultados foram expressos como média ± erro padrão da média (SEM), sendo valores de P menores do que 0,05 considerados significativos. Verificamos que nas linhagens de adenocarcinoma de ovário e colorretal e de glioblastoma (OVCAR-3, HT-29 e U-251) ocorreu uma diminuição significativa na viabilidade celular quando tratadas com a dose de 100μg/mL tanto de carifenona A como de carifenona B, enquanto os compostos japonicina A (50μg/mL) e uliginosina B (20μg/mL) só foram ativos na linhagem OVCAR-3. Dentre as associações com quimioterápicos, a única que apresentou efeito sinérgico foi a combinação de japonicina A e paclitaxel na linhagem OVCAR-3. A partir deste momento selecionamos a japoncina A para dar continuidade aos estudos. Este composto foi avaliado frente a outros tipos de linhagens tumorais, sendo ativa somente em células de adenocarcinoma de ovário e próstata (OVCAR-3 e PC-3). Na linhagem PC-3, a análise do ciclo celular demonstrou decréscimo da fase G1 e indução ao arraste da fase G2, assim como, através da técnica de NMA, foi verificado um aumento de células apoptóticas, quando as células foram tratadas com japonicina A. Estudos moleculares devem ser realizados para melhor entendimento do mecanismo de ação da japonicina A, composto que pode servir de modelo para o desenho de fármacos mais específicos para este tipo de neoplasia. / Due to the great progress in the discovery of new drugs from natural compounds, it has become interesting to evaluate the antiproliferative activity of molecules isolated from plant extracts. This work emphasizes the study of antitumor activity of benzophenones (cariphenone A and cariphenone B) and phloroglucionols (japonicin A and uliginosin B), isolated from Hypericum species native to southern Brazil, H. carinatum and H. myrianthum, respectively, as well as their association with chemotherapeutic drugs used in the clinic. The proposed experiments were performed in vitro using commercially available cell lines. The effect of different doses of these compounds were evaluated via cell viability and survival assay, nuclear morphometric analysis (NMA) and flow cytometry. One way analysis of variance (ANOVA) followed by post hoc tests (Tukey) were utilized for statistical analysis. Results were expressed as mean ± standard error of the mean (SEM), and P values less than 0.05 were considered significant. We found that in ovarian, colorectal (adenocarcinoma) and glioblastoma cell lines (OVCAR-3, HT-29 and U-251) a significant decrease in cell viability occurred when these were treated with a dose of 100μg/mL of cariphenone A and B, while compounds japonicin A (50μg/mL) and uliginosin B (20μg/mL) were active only in OVCAR- 3. Among the associations with chemotherapeutic agents, only japonicin A presented a synergistic effect with paclitaxel in the OVCAR-3 cell line. We then selected japonicin A for evaluation against other cell lines, but its effects were only observed in ovary and prostate adenocarcinoma cell lines (OVCAR-3 e PC-3). In PC-3, the cell cycle revealed a decreased in the G1 phase and induction of G2 arrest, the NMA showed an increase in apoptotic cells when cells were treated with japonicin A. More studies should be conducted to better understand the mechanisms of action of japonicin A, since this compound may serve as pharmacophore model for the design of more specific drugs to treat this tumor type.

Devido ao grande avanço na descoberta de novos fármacos a partir de compostos naturais, tornou-se interessante avaliar o potencial antiproliferativo de moléculas isoladas de extratos de plantas. Este trabalho prioriza o estudo da atividade antitumoral de benzofenonas (carifenona A e carifenona B) e floroglucionóis (japonicina A e uliginosina B), isolados das espécies nativas do sul do Brasil, Hypericum carinatum e Hypericum myrianthum, respectivamente, bem como a associação destes com quimioterápicos utilizados na clínica. Os experimentos propostos foram realizados em modelos in vitro, utilizando diferentes tipos de linhagens tumorais humanas comercialmente disponíveis. Foi avaliado o efeito de diferentes doses destes compostos através de experimentos de viabilidade e sobrevivência celular, análise morfométrica nuclear (NMA) e citometria de fluxo. Na análise estatística foi utilizada a variância de uma via (ANOVA) seguida de teste post-hoc (Tukey). Os resultados foram expressos como média ± erro padrão da média (SEM), sendo valores de P menores do que 0,05 considerados significativos. Verificamos que nas linhagens de adenocarcinoma de ovário e colorretal e de glioblastoma (OVCAR-3, HT-29 e U-251) ocorreu uma diminuição significativa na viabilidade celular quando tratadas com a dose de 100μg/mL tanto de carifenona A como de carifenona B, enquanto os compostos japonicina A (50μg/mL) e uliginosina B (20μg/mL) só foram ativos na linhagem OVCAR-3. Dentre as associações com quimioterápicos, a única que apresentou efeito sinérgico foi a combinação de japonicina A e paclitaxel na linhagem OVCAR-3. A partir deste momento selecionamos a japoncina A para dar continuidade aos estudos. Este composto foi avaliado frente a outros tipos de linhagens tumorais, sendo ativa somente em células de adenocarcinoma de ovário e próstata (OVCAR-3 e PC-3). Na linhagem PC-3, a análise do ciclo celular demonstrou decréscimo da fase G1 e indução ao arraste da fase G2, assim como, através da técnica de NMA, foi verificado um aumento de células apoptóticas, quando as células foram tratadas com japonicina A. Estudos moleculares devem ser realizados para melhor entendimento do mecanismo de ação da japonicina A, composto que pode servir de modelo para o desenho de fármacos mais específicos para este tipo de neoplasia. / Due to the great progress in the discovery of new drugs from natural compounds, it has become interesting to evaluate the antiproliferative activity of molecules isolated from plant extracts. This work emphasizes the study of antitumor activity of benzophenones (cariphenone A and cariphenone B) and phloroglucionols (japonicin A and uliginosin B), isolated from Hypericum species native to southern Brazil, H. carinatum and H. myrianthum, respectively, as well as their association with chemotherapeutic drugs used in the clinic. The proposed experiments were performed in vitro using commercially available cell lines. The effect of different doses of these compounds were evaluated via cell viability and survival assay, nuclear morphometric analysis (NMA) and flow cytometry. One way analysis of variance (ANOVA) followed by post hoc tests (Tukey) were utilized for statistical analysis. Results were expressed as mean ± standard error of the mean (SEM), and P values less than 0.05 were considered significant. We found that in ovarian, colorectal (adenocarcinoma) and glioblastoma cell lines (OVCAR-3, HT-29 and U-251) a significant decrease in cell viability occurred when these were treated with a dose of 100μg/mL of cariphenone A and B, while compounds japonicin A (50μg/mL) and uliginosin B (20μg/mL) were active only in OVCAR- 3. Among the associations with chemotherapeutic agents, only japonicin A presented a synergistic effect with paclitaxel in the OVCAR-3 cell line. We then selected japonicin A for evaluation against other cell lines, but its effects were only observed in ovary and prostate adenocarcinoma cell lines (OVCAR-3 e PC-3). In PC-3, the cell cycle revealed a decreased in the G1 phase and induction of G2 arrest, the NMA showed an increase in apoptotic cells when cells were treated with japonicin A. More studies should be conducted to better understand the mechanisms of action of japonicin A, since this compound may serve as pharmacophore model for the design of more specific drugs to treat this tumor type.

As a part of search for bioactive natural products from the plants in collaboration with the Natural Products Discovery Institute (NPDI), ten plant extracts were investigated for their antiplasmodial activity against Plasmodium falciparum Dd2 strain. Twenty-eight compounds were isolated, and twelve of them were new compounds. The structures of all these compounds were determined by analysis of their mass spectrometric, 1D and 2D NMR, and ECD spectrum. Among these natural products, there were three compounds with good antiplasmodial activity, trichospirolide A with an IC50 value of 1.5 μM, malleastrumolide A with an IC50 value of 2.7 μM, and (+)-lariciresinol with an IC50 value of 3.7 μM. In addition to the studies of drug delivery of bioactive natural product, doxorubicin, a novel thiolated doxorubicin analog were designed and synthesized. Its analogs and PEG stabilizing ligands were then conjugated to gold nanoparticles and the resulting Au-Dox constructs were evaluated by TEM. The release of native drug can be achieved by the action of reducing agents, and that reductive drug release gave the cleanest drug release. / Ph. D. / Natural products from plants have been used as medicines for a very long history, with the best known example of antimalarial drugs. There were two famous antimalarial natural products used as medicines. The first one is an alkaloid, quinine which was isolated from cinchona bark in 1817. Its analog chloroquine was discovered in 1934 and was very effective. But in 1950’s the Plasmodium parasite developed resistance and chloroquine resistant plasmodia were widely spread all over the world. Today, the major antimalarial drug is a sesquiterpenoid, artemisinin which was isolated from artemisia in 1972. Unfortunately, the first report on drug resistance to artemisinin derivative have appeared in 2010. In the future, artemisinin may be useless. So we need to discover new antimalarial natural products. This dissertation focuses on the isolation and structural elucidation of fourteen new natural products with potential antimalarial activities from ten plant extracts.

As part of an International Cooperative Biodiversity Group (ICBG) program and a collaborative research project with the Natural Products Discovery Institute, four plant extracts were investigated for their antiproliferative and antiplasmodial activities. With the guidance of bioassay guided fractionation, two known antiproliferative terpenoids (2.1 and 2.2) were isolated from Hypoestes sp. (Acanthaceae), four known antiplasmodial liminoids (3.1-3.4) were isolated from Carapa guianensis (Meliaceae), one inactive terpenoid (4.1) was isolated from Erica maesta (Ericaceae), and four cerebrosides (4.2-4.5) were obtained from Hohenbergia antillana (Bromeliaceae). The structures of these compounds were elucidated by using 1D (1H and 13C), 2D (HMBC, HSQC, COSY, NOESY) NMR spectroscopy and mass spectrometry. The structures of the compounds were also confirmed by comparing them with reported values from the literature. Compounds 2.1 and 2.2 showed moderate antiproliferative activity against the A2780 human ovarian cancer cell line with IC50 values of 6.9 uM and 3.4 uM, respectively. They also exhibited moderate antiplasmodial activity against chloroquine-resistant Plasmodium falciparum strain Dd2 with IC50 values of 9.9 ± 1.4 uM and 2.8 ± 0.7 uM, respectively. Compounds 3.1 to 3.4 had moderate antiplasmodial activity against Plasmodium falciparum Dd2 strain with IC50 values of 2.0 ± 0.3 uM, 2.1 ± 0.1 uM, 2.1 ± 0.2 uM and 2.8 ± 0.2 uM, respectively. Compounds 4.1 and 4.2 showed very weak antiplasmodial activity against Plasmodium falciparum Dd2 strain, with IC50 values between 5 and 10 ug/mL. / Master of Science / Cancer has a major impact all over the world and is one of the leading causes of death. Malaria remains as one of the most severe tropical diseases in the world. It is a common and often fatal disease caused by a parasitic infection. The treatment of cancer and malaria is a significant challenge, and has become a top priority in drug discovery field. The natural products from plants have been used for medicinal purpose for a long time, and a lot of well-known plant based natural product drugs have been discovered, including anticancer drug paclitaxel, and antimalarial drug chloroquine and artemisinin. However, the resistances for these drugs have developed, and it is urgent to find new drug that can take their place. This research is trying to find promising anticancer and antimalarial natural products from plant extracts. From four plant extracts, two antiproliferative compounds and four antiplasmodial compounds were discovered. In this thesis, the isolation and structure elucidation of these compounds will be discussed.