Naphth[1,2-d]imidazoles Bioactive from ß-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells.

Theranostics combines therapeutic and imaging diagnostic techniques that are extremely dependent on the action of imaging agent, transporter of therapeutic molecules, and specific target ligand, in which fluorescent probes can act as diagnostic agents. In particular, naphthoimidazoles are potential bioactive heterocycle compounds to be used in several biomedical applications. With this aim, a group of seven naphth[1,2-d]imidazole compounds were synthesized from ß-lapachone. Their optical properties and their cytotoxic activity against cancer cells and their compounds were evaluated and confirmed promising values for molar absorptivity coefficients (on the order of 103 to 104), intense fluorescence emissions in the blue region, and large Stokes shifts (20-103 nm). Furthermore, the probes were also selective for analyzed cancer cells (leukemic cells (HL-60). The naphth[1,2-d]imidazoles showed IC50 between 8.71 and 29.92 µM against HL-60 cells. For HCT-116 cells, values for IC50 between 21.12 and 62.11 µM were observed. The selective cytotoxicity towards cancer cells and the fluorescence of the synthesized naphth[1,2-d]imidazoles are promising responses that make possible the application of these components in antitumor theranostic systems.

Synthesis and antileishmanial activity of naphthoquinone-based hybrids / Síntesis y actividad antileishmania de híbridos naftoquinónicos / Síntese e atividade antileishmania de híbridos naftoquinónicos

SUMMARY Introduction: Leishmaniasis is a disease caused by protozoa of the genus Leishmania and is considered endemic in 98 countries. Treatment with pentavalent antimonials has a high toxicity, which motivates the search for effective and less toxic drugs. α- and β-lapachones have shown different biological activities, including antiprotozoa. In recent studies, the isonicotinoylhydrazone and phthalazinylhydrazone groups were considered innovative in the development of antileishmania drugs. Molecular hybridization is a strategy for the rational development of new prototypes, where the main compound is produced through the appropriate binding of pharmacophoric subunits. Aims: To synthesize four hybrids of α- and β-lapachones, together with the isonicotinoylhydrazone and phthalazinylhydrazone groups and to determine the antileishmania activity against the promastigotic forms of L. amazonensis, L. infantum and L. major. Results: β-lapachone derivatives were more active against all tested leishmania species. βACIL (IC50 0.044μM) and βHDZ (IC50 0.023μM) showed 15-fold higher activity than amphotericin B. The high selectivity index exhibited by the compounds indicates greater safety for vertebrate host cells. Conclusion: The results of this work show that the hybrids βACIL and (3HDZ are promising molecules for the development of new antileishmania drugs.

RESUMEN Introducción: Leishmaniasis es una enfermedad causada por protozoos del género Leishmania y se considera endémica en 98 países. El tratamiento con antimoniales pentavalentes tiene una alta toxicidad, lo que motiva la búsqueda de fármacos eficaces y menos tóxico. α- y β-lapachones han mostrado diferentes actividades biológicas, incluido los antiprotozoarios. En estudios recientes, los grupos isonicotinoilhidra-zona y ftalazinilhidrazona se consideraron innovadores en el desarrollo de fármacos antileishmania. La hibridación molecular es una estrategia para el desarrollo racional de nuevos prototipos, donde el compuesto principal se produce a través de la unión apropiada de subunidades farmacofóricas. Objetivos: Sintetizar cuatro híbridos de α- y β-lapachones, junto con los grupos isonicotinoilhidrazona y ftalazinilhidrazona y determinar la actividad antileishmania frente a las formas promastigotas de L. amazonensis, L. infantum y L. major. Resultados: Los derivados de β-lapachone fueron más activos contra todas las especies de leishmania probadas. La βACIL (CI50 0,044μM) y βHDZ (CI50 0,023μM) mostraron actividad 15 veces mayor que la anfotericina B. El alto índice de selectividad que presentan los compuestos indica una mayor seguridad para las células huésped del vertebrado. Conclusión: Los resultados de este trabajo demuestran que los híbridos (ACIL y (HDZ son moléculas prometodoras para el desarrollo de nuevos fármacos antileishmania.

RESUMO Introdução: A leishmaniose é uma doença causada por protozoários do género Leishmania e é considerada endémica em 98 países. O tratamento com antimoniais pentavalentes apresenta alta toxicidade, o que motiva a pesquisa por medicamentos eficazes e menos tóxicos. α- e β-lapachones tém mostrado diferentes atividades biológicas, incluindo antiprotozoários. Em estudos recentes, os grupos isonicotinoilhi-drazona e ftalazinilhidrazona foram considerados inovadores no desenvolvimento de drogas antileishmania. A hibridização molecular é uma estratégia para o desenvolvimento racional de novos protótipos, onde o composto principal é produzido através da ligação apropriada de subunidades farmacofóricas. Objetivos: Sintetizar quatro híbridos de α- e β-lapachones, juntamente com os grupos isonicotinoil-hidra-zona e ftalazinilhidrazona e determinar a atividade antileishmania contra as formas promastigóticas de L. amazonensis, L. infantum e L. major. Resultados: Os derivados de β-lapachona foram mais ativos contra todas as espécies de leishmania testadas. BACIL (IC50 0,044 μM) e βHDZ (IC50 0,023 μM) apresentaram atividade 15 vezes maior do que a anfotericina B. O alto índice de seletividade dos compostos indica maior segurança para células hospedeiras de vertebrados. Conclusaõ: Os resultados deste trabalho mostram que os híbridos βACIL e βHDZ são moléculas promissoras para o desenvolvimento de novos fármacos antileishmania.

Cellular and biochemical antileukemic mechanisms of the meroterpenoid Oncocalyxone A.

Oncocalyxone A, a 1,4-benzoquinone derived from Cordia oncocalyx, exhibits anti-inflammatory, antimicrobial and antidiabetic properties. The aim of this study was to (1) examine the cytotoxic actions of oncocalyxone A on human normal and tumor cell lines and (2) determine mechanistic actions underlying effects upon leukemia cells using cellular and molecular techniques. Antiproliferative studies on cancer cell lines, peripheral blood mononuclear cells, and human erythrocytes were performed using colorimetric assays. To understand cytotoxicity, assessments were performed with HL-60 leukemia cells (8, 16.5, or 33 µM) after 24 hr incubation using light and fluorescence microscopy, trypan blue, flow cytometry, Comet assay, western blot of caspases and poly-ADP-ribose polymerase (PARP), and effects on topoisomerase I and II. Oncocalyxone A exhibited cytotoxic action upon HL-60 cells and dividing leukocytes, but minimal hemolytic action on erythrocytes. Mechanistic investigations demonstrated reduction of cell viability, loss of membrane integrity, cell shrinking, chromatin condensation, blebbings, externalization of phosphatidylserine, caspase activation, PARP cleavage, mitochondrial depolarization, and DNA damage. Pre-treatment with N-acetylcysteine 4 mM significantly reduced DNA damage and prevented membrane integrity loss. Oncocalyxone A displayed free radical dependent antileukemic activity via apoptotic pathways and induced DNA damage in HL-60 cells. Oncocalyxone A possesses structural chemical simplicity enabling it to be a cost-effective alternative. These properties justify further improvements to enhance activity and selectivity and the development of pharmaceutical formulations. Abbreviations Acridine orange, AO; ANOVA, analysis of variance; BSA, bovine serum albumin; DI, Damage Index; DMSO, dimethylsulfoxide; EC50, effective concentration 50%; EDTA, ethylenediamine tetraacetic acid; EB, ethidium bromide; HCT-116, colon carcinoma line; HL-60, promyelocytic leukemia line; IC50, inhibitory concentration 50%; MTT, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide; OVCAR-8, ovarian carcinoma line; NAC, N-acetylcysteine, PBMC, peripheral blood mononuclear cells; PBS, phosphate-buffered saline; PI, propidium iodide; PARP, poly-ADP-ribose polymerase; RPMI-1640, Roswell Park Memorial Institute medium; SF-295, glioblastoma line; ROS, reactive oxygen species; 7-AAD, 7-amino-actinomycin D; H2-DCF-DA, 7'-dichlorodihydrofluorescein diacetate.

Toxicological, chemopreventive, and cytotoxic potentialities of rare vegetal species and supporting findings for the Brazilian Unified Health System (SUS).

Caatinga flora which are found in a poor Brazilian region contain a substantial number of endemic taxa with biomedical and social importance for regional communities. This study examined the antioxidant and cytotoxic potential of 35 samples (extracts/fractions) from 12 Caatinga species and determined the antiproliferative and genotoxic action of dichloromethane fraction from Mimosa caesalpiniifolia stem bark (DC-Mca) on human and vegetal cells. Samples were assessed for chemopreventive ability, toxic effects on Artemia salina shrimp as well as cytotoxicity on tumor cell lines and erythrocytes. DC-Mca was also tested with respect to antiproliferative and genotoxic effects upon normal leukocytes and meristematic cells from A. cepa roots. Some extracts reduced free radical levels >95% and 7 samples exhibited a lethal concentration (LC) 50 < 100 µg/ml upon Artemia salina larvae. Eight samples displayed in vitro antitumor effects and three produced hemolysis. Data also demonstrated the pharmacological significance of bioactive extracts from Brazilian semi-arid region. There was no significant relationship between antioxidant, toxic, and antiproliferative activities, and that these properties were dependent upon the extractant. DC-Mca contained betulinic acid as main compound (approximately 70%), which showed higher (1) cytotoxic activity on cancer cell lines and dividing leukocytes, (2) reduced mitotic index of Allium cepa roots, and (3) induced cell cycle arrest and chromosomal bridges, thereby providing native promising sources for phytotherapy development. ABBREVIATIONS: ABTS: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid); AcOH: ethyl acetate; ANOVA: analysis of variance; SUS: Brazilian Unified Health System; DC-Mca: dichloromethane fraction from Mimosa caesalpiniifolia stem bark; DMSO: dimethylsulfoxide; DPPH: 1,1-diphenyl-2-picrylhydrazyl; EC50: effective concentration 50%; EtOAc: ethyl acetate; FDA: Food and Drug Administration; GC-Qms: gas chromatograph quadrupole mass spectrometer; GI: genotoxic index; HCT-116: colon carcinoma line; HL-60: promyelocytic leukemia line; HPLC: high-performance liquid chromatography; HRAPCIMS: high resolution atmospheric pressure chemical ionization mass spectrum; IC50: inhibitory concentration 50%; LC50: lethal concentration 50%; MeOH = methyl alcohol; MI: mitotic index; MTT: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide; MutI: mutagenic index; OVCAR-8 = ovarian carcinoma line; PBMC: peripheral blood mononuclear cells; RPMI-1640: Roswell Park Memorial Institute medium; SF-295: glioblastoma line; TEAC: trolox equivalent antioxidant capacity; TLC: thin-layer chromatography; Trolox: 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid.

Uma revisão das atividades biológicas da trans-desidrocrotonina, um produto natural obtido de Croton cajucara / A review of the biologic activities of trans-dehydrocrotonin, a natural product obtained from Croton cajucara

Croton cajucara Beth (Euphorbiaceae) uma espécie medicinal nativa da região Amazônica do Brasil, onde é vulgarmente conhecida como 'sacaca', representa um recurso terapêutico eficaz no tratamento e cura de várias doenças. O metabólito majoritário trans-desidrocrotonina (DCTN), isolado das cascas do caule desta planta, encontra-se correlacionado com grande parte das propriedades medicinais da sacaca. Este artigo de revisão, descreve os resultados fitoquímicos e farmacológicos que foram realizados com o diterpeno do tipo clerodano DCTN, bem como seus derivados semi-sintéticos. Adicionalmente, apresenta perspectivas para a biodisponibilização deste protótipo de fármaco em nanosistemas.

Croton cajucara Beth (Euphorbiaceae) is a plant found in the Amazonian Region of North Brazil, where it is popularly known as sacaca. The major secondary metabolite, trans-dehydrocrotonin (DCTN) a clerodane-type diterpene, isolated from the stem bark is a chief bioactive compound of Croton cajucara. This review describes results of extensive pharmacological studies of DCTN, as well as its semi-synthetic derivatives, and also presents insights into the use of DCTN as a therapeutic agent and some potential advantages of its incorporation in drug delivery systems.