Ana Carolina Leal

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A series of new heterocyclic derivatives of ursolic acid 1 were synthesized and evaluated for their antiproliferative activity against AsPC-1 pancreatic cancer cells. Compounds 24-32, with an α,β unsaturated ketone in conjugation with an heterocyclic ring in ring A have improved antiproliferative activities. Compound 32 is the most active compound with an(More)
This review highlights the potential of natural and semisynthetic ursane-type triterpenoids as candidates for the design of multi-target bioactive compounds, with focus on their anticancer effects. A brief illustration of the biosynthesis, sources, and general biological effects of the main classes of naturally occurring pentacyclic triterpenoids (PTs) are(More)
Bone metastases, present in 70% of patients with metastatic breast cancer, lead to skeletal disease, fractures and intense pain, which are all believed to be mediated by tumor cells. Engraftment of tumor cells is supposed to be preceded by changes in the target tissue to create a permissive microenvironment, the pre-metastatic niche, for the establishment(More)
Coagulation proteins play a critical role in numerous aspects of tumor biology. Cancer cells express tissue factor (TF), the protein that initiates blood clotting, which frequently correlates with processes related to cell aggressiveness, including primary tumor growth, invasion, and metastasis. It has been demonstrated that TF gets incorporated into(More)
Bovine papillomavirus type 4 (BPV-4) and bracken fern are cofactors in the carcinogenesis of the upper gastrointestinal (GI) tract of cattle. An experimental in vitro model system has been developed to analyse the co-operation between the viral transforming protein E7, the cellular ras oncogene and quercetin, one of the mutagens of bracken fern, during(More)
BACKGROUND Invasion of mosquito salivary glands (SGs) by Plasmodium falciparum sporozoites is an essential step in the malaria life cycle. How infection modulates gene expression, and affects hematophagy remains unclear. PRINCIPAL FINDINGS Using Affimetrix chip microarray, we found that at least 43 genes are differentially expressed in the glands of(More)
A series of new oleanane imidazole carbamates, N-acylimidazoles or N-alkylimidazoles were synthesized, characterized and evaluated for their antiproliferative activity in AsPC-1 pancreatic cancer cells. Structure-activity relationship analysis revealed that the N-alkylimidazole 27 was the most active compound with apoptosis induction abilities correlated(More)
The objective of this study was to assess the effects of nitric oxide (NO) on heparin-induced capacitation in vitro of fresh bull sperm, through the addition of Nomega-nitro-l-arginine methyl ester (L-NAME, a NO-synthesis inhibitor) and l-arginine (L-Arg, a NO-synthesis precursor) to the capacitation medium. In Experiment 1, different concentrations of(More)
A new, straightforward and high yielding procedure to convert oleanolic acid derivatives into the corresponding δ-hydroxy-γ-lactones, by using the convenient oxidizing agent magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) in refluxing acetonitrile, is reported. In addition, a two-step procedure for the preparation of oleanolic 12-oxo-28-carboxylic(More)
A series of ursolic acid ((1S,2R,4aS,6aR,6aS,6bR,8aR,10S,12aR,14bS)-10-hydroxy-1,2,6a,6b,9,9,12a-heptamethyl-2,3,4,5,6,6a,7,8,8a,10,11,12,13,14b-tetradecahydro-1H-picene-4a-carboxylic acid) derivatives with a 12-fluoro-13,28β-lactone moiety were synthesized using the electrophilic fluorination reagent Selectfluor. The antiproliferative effects of these(More)
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