RESUMO
A new chromone, 2-(2-hydroxy-2-phenylethyl)chromone (1), was isolated together with ten known phenylethyl chromones from MeOH extracts of agarwood (Aquilaria filaria). The selected compounds were evaluated in an antiproliferative assay against five human tumor cell lines, including a multidrug-resistant cell line. They were also tested for antitumor promoting activity, as mediated by 12-O-tetradecanoylphorbol-13-acetate-induced activation of the Epstein-Barr virus early antigen in Raji cells. Among all compounds, 4',7-dimethyoxy-6-hydroxychromone (2) displayed broad spectrum antiproliferative activity against all tumor cell lines tested with IC50 values of 25-38 µM, while 8 was selectively inhibitory against multidrug-resistant cells. All tested compounds suppressed tumor promotion at noncytotoxic concentrations. 4',6-Dihydroxyphenylethylchromone (7) exhibited the most potent effect with an IC50 value of 319 mol ratio relative to 12-O-tetradecanoylphorbol-13-acetate. This study is the first to report the antitumor promoting activity of 2-(2-phenylethyl)chromone derivatives, as well as the selective antiproliferative activity of 8 against a multidrug-resistant tumor cell line.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Cromonas/química , Cromonas/farmacologia , Thymelaeaceae/química , Antígenos Virais/metabolismo , Antineoplásicos/isolamento & purificação , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Cromonas/isolamento & purificação , Resistencia a Medicamentos Antineoplásicos , Flavonoides/química , Flavonoides/farmacologia , Humanos , Concentração Inibidora 50 , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Aplysiatoxin (ATX) is a protein kinase C (PKC) activator with potent tumor-promoting activity. In contrast, 10-methyl-aplog-1 (1), a simplified analog of ATX, was anti-proliferative towards several cancer cell lines without significant tumor-promoting and proinflammatory activities. To determine the effects of the phenolic group on the biological activities of 1, we synthesized new derivatives (2, 3) that lack the phenolic hydroxyl group and/or the aromatic ring. Compound 2, like 1, showed potent anti-proliferative activity against several cancer cell lines, but little with respect to tumor-promoting and proinflammatory activities. In contrast, 3 exhibited weaker growth inhibitory activity, and promoted inflammation and tumorigenesis. The binding affinity of 3 for PKCδ, which is involved in growth inhibition and apoptosis, was several times lower than those of 1 and 2, possibly due to the absence of the hydrogen bond and CH/π interaction between its side chain and either Met-239 or Pro-241 in the PKCδ-C1B domain. These results suggest that both the aromatic ring and phenolic hydroxyl group can suppress the proinflammatory and tumor-promoting activities of 1 and, therefore, at least the aromatic ring in the side chain of 1 is indispensable for developing anti-cancer leads with potent anti-proliferative activity and limited side effects. In accordance with the binding affinity, the concentration of 3 necessary to induce PKCδ-GFP translocation to the plasma membrane and perinuclear regions in HEK293 cells was higher than that of 1 and 2. However, the translocation profiles for PKCδ-GFP due to induction by 1-3 were similar.
Assuntos
Carcinógenos/química , Carcinógenos/farmacologia , Toxinas de Lyngbya/química , Toxinas de Lyngbya/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Camundongos , Modelos Moleculares , Estrutura Molecular , Proteína Quinase C/química , Proteína Quinase C/metabolismo , Proteína Quinase C-delta/química , Proteína Quinase C-delta/metabolismo , Relação Estrutura-AtividadeRESUMO
A series of 2-oxindole derivatives were synthesized and evaluated for cytotoxic activity against different human and murine cancer cell lines and cancer chemopreventive activity. Among the tested compounds VS-06, 08, 12 and 17 displayed cytotoxic activity in the range of 5.0 to 8.5 pM against human T-lymphocyte cells (CEM). Results showed that molecules with electron withdrawing substituent at 4 position of N-phenylacetamide group exhibited an increase in activity against the human tumor cell line CEM. The cancer chemo- preventive effect of VS-01 (IC50 = 451 nM) displayed equipotent activity in comparison to standard oleanolic acid (IC50 = 449 nM).
Assuntos
Anticarcinógenos/síntese química , Antineoplásicos/síntese química , Animais , Anticarcinógenos/farmacologia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Humanos , Relação Estrutura-AtividadeRESUMO
Chemoprevention of human cancer appears to be a feasible strategy for cancer control, especially when chemopreventive intervention is involved during early stages of the carcinogenesis process. As a part of our ongoing research program into new chemopreventive agents, herein are reported the isolation, structural elucidation, and biological evaluation of 10 new (1-10) and three known (11-13) sesquiterpenes with a dihydro-ß-agarofuran skeleton from the leaves of Maytenus jelskii Zahlbr. Their stereostructures have been elucidated by means of spectroscopic analysis, including 1D and 2D NMR techniques, ECD studies, and biogenetic considerations. The isolated metabolites and eight previously reported sesquiterpenes (14-21) were screened for their antitumor-promoting activity using a short-term in vitro assay for Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Six compounds from this series (4, 5, 11, and 13-15) were found to exhibit higher efficacies than ß-carotene, used as reference inhibitor for EBV-EA activation. In particular, promising antitumor activity was observed for compound 5, exhibiting inhibition even at the lowest concentration assayed (10 mol ratio/TPA). Preliminary structure-activity relationship analysis revealed that the acetate, benzoate, and hydroxy groups are the most desirable substituents on the sesquiterpene scaffold for activity in the EBV-EA activation assay.
Assuntos
Anticarcinógenos , Maytenus/química , Sesquiterpenos , Anticarcinógenos/química , Anticarcinógenos/isolamento & purificação , Anticarcinógenos/farmacologia , Antígenos Nucleares do Vírus Epstein-Barr/efeitos dos fármacos , Antígenos Nucleares do Vírus Epstein-Barr/farmacologia , Humanos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peru , Folhas de Planta/química , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Estereoisomerismo , Relação Estrutura-Atividade , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Six acetophenone derivatives, acronyculatins I (1), J (2), K (3), L (4), N (5), and O (6), were recently isolated from Acronychia trifoliolata, and the structure of the known acronyculatin B (7) was revised. Because of the limited quantities of isolated products as well as their structure similarity, racemic acronyculatins I-L, N, O, and B (1-7) were synthesized to confirm their structures and to obtain sufficient material for biological evaluation. Trihydroxyacetophenone was converted to the target compounds by various sequences of hydroxy group protection, allylation or prenylation, and epoxidation followed by cyclization. C-Prenylations were carried out by direct addition of a prenyl group or through 1,3- or 3,3-sigmatropic rearrangement. The synthesized racemic compounds were evaluated in an anti-tumor-promoting assay using the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All tested compounds significantly inhibited EBV-EA activation. Especially, racemic acronyculatin I (1) displayed the most potent inhibitory effects, with an IC50 value of 7.3 µM.
Assuntos
Acetofenonas/síntese química , Acetofenonas/farmacologia , Rutaceae/química , Acetofenonas/química , Antígenos Virais/efeitos dos fármacos , Carcinógenos/farmacologia , Herpesvirus Humano 4/efeitos dos fármacos , Humanos , Estrutura Molecular , Neoplasias , Estereoisomerismo , Relação Estrutura-Atividade , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Aplog-1 is a simplified analog of debromoaplysiatoxin (DAT) with potent tumor-promoting and proinflammatory activities. Aplog-1 and DAT exhibited anti-proliferative activities against several human cancer cell lines, whereas aplog-1 did not have tumor-promoting nor proinflammatory activities. We have recently found 10-methyl-aplog-1 (1) to have strong anti-proliferative activity compared with aplog-1. To further investigate the structural factors involved in the tumor-promoting, proinflammatory, and anti-proliferative activities, two dimethyl derivatives of aplog-1 (2, 3) were synthesized, where two methyl groups were installed at positions 4 and 10 or 10 and 12. 10,12-Dimethyl-aplog-1 (2) had stronger inhibitory effects on the growth of several human cancer cell lines than 1 and DAT, but exhibited no tumor-promoting and proinflammatory activities. In contrast, 4,10-dimethyl-aplog-1 (3) displayed weak tumor-promoting and proinflammatory activities along with anti-proliferative activity similar to that of 1 and DAT. Compound 2 would be the optimized seed for anticancer drugs among the simplified analogs of DAT.
Assuntos
Antineoplásicos/síntese química , Carcinógenos/síntese química , Lactonas/síntese química , Toxinas de Lyngbya/síntese química , Animais , Antineoplásicos/farmacologia , Carcinógenos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Lactonas/farmacologia , Toxinas de Lyngbya/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Papiloma/induzido quimicamente , Papiloma/patologia , Neoplasias Cutâneas/induzido quimicamente , Neoplasias Cutâneas/patologia , Relação Estrutura-AtividadeRESUMO
A series of 2-(4-methylbenzyl)-5,6-substituted-imidazo[2,1-b][1,3,4]thiadiazole derivatives were synthesized, characterized and evaluated for antiproliferative activity and cancer chemopreventive activity. Results showed that molecules with formyl and thiocyanate substiments at the 5 position exhibited an increase in activity against the full panel of 60 human tumor cell lines at a minimum of five concentrations at 10-fold dilutions. Derivative 22 displayed significant in vino anticancer activity against colon cancer (MID GI50 = 0.75 µM). The cancer chemopreventive effect of 19 (IC50 = 489 nM) was almost equipotent to standard oleanolic acid (IC50 = 449 nM).
Assuntos
Anticarcinógenos/síntese química , Antineoplásicos/síntese química , Imidazóis/síntese química , Tiadiazóis/síntese química , Animais , Anticarcinógenos/farmacologia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Feminino , Humanos , Imidazóis/farmacologia , Camundongos , Camundongos Endogâmicos ICR , Tiadiazóis/farmacologiaRESUMO
Aplog-1 is a simplified analog of the tumor-promoting aplysiatoxin with anti-proliferative and cytotoxic activities against several cancer cell lines. Our recent findings have suggested that protein kinase Cδ (PKCδ) could be one of the target proteins of aplog-1. In this study, we synthesized amide-aplog-1 (3), in which the C-1 ester group was replaced with an amide group, to improve chemical stability in vivo. Unfortunately, 3 exhibited seventy-fold weaker binding affinity to the C1B domain of PKCδ than that of aplog-1, and negligible anti-proliferative and cytotoxic activities even at 10(-4) M. A conformational analysis and density functional theory calculations indicated that the stable conformation of 3 differed from that of aplog-1. Since 27-methyl and 27-methoxy derivatives (1, 2) without the ability to bind to PKC isozymes exhibited marked anti-proliferative and cytotoxic activities at 10(-4) M, 3 may be an inactive control to identify the target proteins of aplogs.
Assuntos
Amidas/química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Toxinas de Lyngbya/síntese química , Toxinas de Lyngbya/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Técnicas de Química Sintética , Humanos , Isoenzimas/antagonistas & inibidores , Toxinas de Lyngbya/química , Modelos Moleculares , Conformação Molecular , Proteína Quinase C-delta/antagonistas & inibidores , Relação Estrutura-AtividadeRESUMO
Two jasmonate derivatives, glucosylcucurbic acid (1) and methyl glucosylcucurbate (2), were isolated from the MeOH extract of defatted shea (Vitellaria paradoxa; Sapotaceae) kernels. These and their deglucosylated derivatives, cucurbic acid (3) and methyl cucurbate (4), were evaluated for their melanogenesis-inhibitory and cancer chemopreventive potencies. Compounds 1, 3, and 4 exhibited potent melanogenesis-inhibitory activities in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16 melanoma cells. Western-blot analysis revealed that compounds 1 and 3 reduced the protein levels of MITF (=microphthalmia-associated transcription factor), tyrosinase, TRP-1 (=tyrosine-related protein 1), and TRP-2 mostly in a concentration-dependent manner. In addition, compound 1 exhibited inhibitory effects against Epstein-Barr virus early antigen (EBV-EA) activation induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, against TPA-induced inflammation in mice, and against skin tumor promotion in an in vivo two-stage mouse skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator, and with TPA as promoter.
Assuntos
Anticarcinógenos/química , Anticarcinógenos/farmacologia , Glucosídeos/farmacologia , Melaninas/metabolismo , Oxilipinas/farmacologia , Sapotaceae/química , Animais , Antígenos Virais/metabolismo , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral/efeitos dos fármacos , Glucosídeos/química , Humanos , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/patologia , Camundongos Endogâmicos , Estrutura Molecular , Monofenol Mono-Oxigenase/metabolismo , Oxirredutases/metabolismo , Oxilipinas/química , Extratos Vegetais/química , Sementes/química , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia , Acetato de Tetradecanoilforbol/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , alfa-MSH/metabolismo , alfa-MSH/farmacologiaRESUMO
Ten new 3,4-seco betulinic acid (BA) derivatives were designed and synthesized. Among them, compounds 7-15 exhibited enhanced chemopreventive ability in an in vitro short-term 12-O-tetradecanoylphorbol-13-acetate (TPA) induced Epstein-Barr virus early antigen (EBV-EA) activation assay in Raji cells. Specifically, analogs with a free C-28 carboxylic acid, including 7, 8, 11, and 13, inhibited EBV-EA activation significantly. The most potent compound 8 displayed 100% inhibition at 1×10(3) mol ratio/TPA and 73.4%, 35.9%, and 8.4% inhibition at 5×10(2), 1×10(2), and 1×10 mol ratio/TPA, respectively, comparable with curcumin at high concentration and better than curcumin at low concentration. The potent chemopreventive activity of novel seco A-ring BAs (8 and 11) was further confirmed in an in vivo mouse skin carcinogenesis assay.
Assuntos
Anticarcinógenos/química , Anticarcinógenos/farmacologia , Neoplasias/prevenção & controle , Triterpenos/química , Triterpenos/farmacologia , Animais , Linhagem Celular , Herpesvirus Humano 4/efeitos dos fármacos , Humanos , Camundongos , Triterpenos Pentacíclicos , Triterpenos/síntese química , Ácido BetulínicoRESUMO
Compared to the current knowledge on cancer chemotherapeutic agents, only limited information is available on the ability of organic compounds, such as drugs and/or natural products, to prevent or delay the onset of cancer. In order to evaluate chemical chemopreventive potentials and design novel chemopreventive agents with low to no toxicity, we developed predictive computational models for chemopreventive agents in this study. First, we curated a database containing over 400 organic compounds with known chemoprevention activities. Based on this database, various random forest and support vector machine binary classifiers were developed. All of the resulting models were validated by cross validation procedures. Then, the validated models were applied to virtually screen a chemical library containing around 23,000 natural products and derivatives. We selected a list of 148 novel chemopreventive compounds based on the consensus prediction of all validated models. We further analyzed the predicted active compounds by their ease of organic synthesis. Finally, 18 compounds were synthesized and experimentally validated for their chemopreventive activity. The experimental validation results paralleled the cross validation results, demonstrating the utility of the developed models. The predictive models developed in this study can be applied to virtually screen other chemical libraries to identify novel lead compounds for the chemoprevention of cancers.
Assuntos
Anticarcinógenos/química , Anticarcinógenos/farmacologia , Desenho de Fármacos , Máquina de Vetores de Suporte , Anticarcinógenos/síntese química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Desenho Assistido por Computador , Bases de Dados de Produtos Farmacêuticos , Humanos , Modelos Biológicos , Neoplasias/tratamento farmacológico , Relação Quantitativa Estrutura-AtividadeRESUMO
A new and efficient total synthesis has been developed to obtain plagiochin G (22), a macrocyclic bisbibenzyl, and four derivatives. The key 16-membered ring containing biphenyl ether and biaryl units was closed via an intramolecular SNAr reaction. All synthesized macrocyclic bisbibenzyls inhibited Epstein-Barr virus early antigen (EBVEA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells and, thus, are potential cancer chemopreventive agents.
RESUMO
Two of each semisynthetic lanostane- and cycloartane-type triterpenes with a cyano-enone functionality, i.e., 13 and 18, and 23 and 28, respectively, sixteen of their synthetic intermediates, 9-12, 14-17, 19-22, and 24-27, along with seven semisynthetic oxygenated triterpene acetates, 29-35, and eight natural hydroxy triterpenes, 1-8, were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK-BR-3) cancer cell lines. One natural triterpene, 8, and ten semisynthetic triterpenes, 9, 13, 15, 18, 23, 25, 28, 29, 32, and 33, exhibited potent cytotoxicities against one or more cell lines with IC50 values in the range of 1.4-9.9â µM. Two lanostane-type triterpenes with a cyano-enone functionality, 3-oxolanosta-1,8,24-triene-2-carbonitrile (13) and 3-oxolanosta-1,8-diene-2-carbonitrile (18), induced apoptosis in HL60 cells, as observed by membrane phospholipid exposure in flow cytometry. Western blot analysis showed that 13 and 18 significantly reduced procaspases-3, -8, and -9, and increased cleaved caspases-3, -8, and -9. These findings indicated that compounds 13 and 18 induced apoptosis in HL60 cells via both the mitochondrial and the death receptor-mediated pathways. In addition, upon evaluation of the inhibitory effects on EpsteinBarr virus early antigen (EBV-EA) activation induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, seven natural triterpenes, 1-6 and 8, and ten semisynthetic triterpenes, 9, 10, 14, 15, 19, 20, 24, 25, 29, and 30, exhibited inhibitory effects which were higher than that of ß-carotene, a vitamin A precursor studied widely in cancer-chemoprevention animal models.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Triterpenos/química , Triterpenos/farmacologia , Antígenos Virais/metabolismo , Antineoplásicos Fitogênicos/química , Caspases/metabolismo , Linhagem Celular Tumoral , Técnicas de Química Sintética , Ensaios de Seleção de Medicamentos Antitumorais , Células HL-60/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Relação Estrutura-Atividade , Acetato de Tetradecanoilforbol/farmacologia , Triterpenos/síntese químicaRESUMO
Nine limonoids, 1-9, one apocarotenoid, 11, one alkaloid, 12, and one steroid, 13, from the leaf extract; and one triterpenoid, 10, five steroids, 14-18, and two flavonoids, 19 and 20, from the bark extract of Melia azedarach L. (Chinaberry tree; Meliaceae) were isolated. Among these compounds, three compounds, 4-6, were new, and their structures were established as 3-deacetyl-28-oxosalannolactone, 3-deacetyl-28-oxosalanninolide, and 3-deacetyl-17-defurano-17,28-dioxosalannin, respectively, on the basis of extensive spectroscopic analyses and comparison with literature data. All of the isolated compounds were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK-BR-3) cancer cell lines. 3-Deacetyl-4'-demethyl-28-oxosalannin (3) against HL60 and AZ521 cells, and methyl kulonate (10) against HL60 cells exhibited potent cytotoxicities with IC50 values in the range of 2.8-5.8 µM. In addition, upon evaluation of compounds 1-13 against production of nitric oxide (NO) in mouse macrophage RAW 264.7 cells induced by lipopolysaccharide (LPS), seven, i.e., trichilinin B (1), 4, ohchinin (7), 23-hydroxyohchininolide (8), 21-hydroxyisoohchininolide (9), 10, and methyl indole 3-carboxylate (12), inhibited production of NO with IC50 values in the range of 4.6-87.3 µM with no, or almost no, toxicity to the cells (IC50 93.2-100 µM). Western blot analysis revealed that compound 7 reduced the expression levels of the inducible NO synthase (iNOS) and COX-2 proteins in a concentration-dependent manner. Furthermore, compounds 5, 6, 13, and 18-20 exhibited potent inhibitory effects (IC50 299-381 molar ratio/32 pmol TPA) against Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cell line.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Limoninas/farmacologia , Melia azedarach/química , Óxido Nítrico/metabolismo , Animais , Antineoplásicos Fitogênicos/química , Linhagem Celular Tumoral , Inibidores de Ciclo-Oxigenase 2/farmacologia , Inibidores de Ciclo-Oxigenase/farmacologia , Células HL-60 , Humanos , Concentração Inibidora 50 , Limoninas/química , Limoninas/isolamento & purificação , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Estrutura Molecular , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/metabolismo , Casca de Planta/química , Folhas de Planta/químicaRESUMO
Seventeen limonoids (tetranortriterpenoids), 1-17, including three new compounds, i.e., 17-defurano-17-(2,5-dihydro-2-oxofuran-3-yl)-28-deoxonimbolide (14), 17-defurano-17-(2ξ-2,5-dihydro-2-hydroxy-5-oxofuran-3-yl)-28-deoxonimbolide (15), and 17-defurano-17-(5ξ-2,5-dihydro-5-hydroxy-2-oxofuran-3-yl)-2',3'-dehydrosalannol (17), were isolated from an EtOH extract of the leaf of neem (Azadirachta indica). The structures of the new compounds were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Upon evaluation of the cytotoxic activities of these compounds against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK-BR-3) cancer cell lines, seven compounds, i.e., 1-3, 12, 13, 15, and 16, exhibited potent cytotoxicities with IC50 values in the range of 0.1-9.9â µM against one or more cell lines. Among these compounds, cytotoxicity of nimonol (1; IC50 2.8â µM) against HL60 cells was demonstrated to be mainly due to the induction of apoptosis by flow cytometry. Western blot analysis suggested that compound 1 induced apoptosis via both the mitochondrial and death receptor-mediated pathways in HL60 cells. In addition, when compounds 1-17 were evaluated for their inhibitory activities against melanogenesis in B16 melanoma cells, induced with α-melanocyte-stimulating hormone (α-MSH), seven compounds, 1, 2, 4-6, 15, and 16, exhibited inhibitory activities with 31-94% reduction of melanin content at 10â µM concentration with no or low toxicity to the cells (82-112% of cell viability at 10â µM). All 17 compounds were further evaluated for their inhibitory effects against the EpsteinBarr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells.
Assuntos
Azadirachta/química , Limoninas/farmacologia , Limoninas/toxicidade , Animais , Antígenos Virais/metabolismo , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/toxicidade , Apoptose/efeitos dos fármacos , Azadirachta/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HL-60 , Herpesvirus Humano 4/efeitos dos fármacos , Herpesvirus Humano 4/metabolismo , Humanos , Limoninas/química , Limoninas/isolamento & purificação , Melaninas/metabolismo , Camundongos , Conformação Molecular , Folhas de Planta/química , Folhas de Planta/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Ativação Viral/efeitos dos fármacos , alfa-MSH/metabolismoRESUMO
ABSTRACT: A series of new ß-isatin aldehyde-N,N'-thiocarbohydrazone, bis-ß-isatin thiocarbohydrazones, bis-ß-isatin carbohydrazones was synthesized by condensation of 5-substituted isatin with thiocarbohydrazide or carbohydrazide. The chemical structures of the newly synthesized compounds were confirmed by FT-IR, 1H NMR, and mass spectral analysis. The synthesized compounds were evaluated for in vitro antiviral activity against various strains of DNA and RNA viruses, but exhibited moderate antiviral activity compared with the reference compounds. Among all the compounds 6c exhibited the highest chemoprevention activity in a two-stage mouse-skin carcinogenesis test.
RESUMO
Debromoaplysiatoxin (DAT) is a tumor promoter isolated from sea hare and exhibits anti-proliferative activity against several cancer cell lines. To clarify key residues that are responsible for its tumor-promoting activity, we focused on the chiral methoxy group in the side chain, whose role had not yet been discussed or examined before. Demethoxy-DAT (8) was derived from DAT and we evaluated its tumor-promoting activity, anti-proliferative activity, and ability to bind to protein kinase C (PKC) isozymes. Compound 8 showed somewhat weaker tumor-promoting activity than that of DAT both in vitro and in vivo, but showed higher anti-proliferative activity against several cancer cell lines. Although the affinity to novel PKC isozymes of 8 was comparable to that of DAT, the affinity to conventional PKC isozymes decreased slightly. These results suggest that the methoxy group of DAT is one of the key residues critical for tumor-promoting activity but not for anti-proliferative activity. Since the methoxy group has little influence on the molecular hydrophobicity, this is the first report showing that structural factors other than hydrophobicity in the side chain of DAT affected its biological activities.
Assuntos
Antineoplásicos/química , Toxinas de Lyngbya/química , Antineoplásicos/metabolismo , Antineoplásicos/toxicidade , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Toxinas de Lyngbya/metabolismo , Toxinas de Lyngbya/toxicidade , Ligação Proteica , Proteína Quinase C/química , Proteína Quinase C/genética , Proteína Quinase C/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMO
We have recently developed a simplified analog of aplysiatoxin (aplog-1) as an activator of protein kinase C (PKC) with anti-proliferative activity like bryostain 1. To identify sites in aplog-1 that could be readily modified to optimize therapeutic performance and to develop a molecular probe for examining the analog's mode of action, substituent effects on the phenol ring were systematically examined. Whereas hydrophilic acetamido derivatives were less active than aplog-1 in inhibiting cancer cell growth and binding to PKCδ, introduction of hydrophobic bromine and iodine atoms enhanced both biological activities. The anti-proliferative activity was found to correlate closely with molecular hydrophobicity, and maximal activity was observed at a logP value of 4.0-4.5. On the other hand, an induction test with Epstein-Barr virus early antigen demonstrated that these derivatives have less tumor-promoting activity in vitro than aplog-1 regardless of the hydrophobicity of their substituents. These results would facilitate rapid preparation of molecular probes to examine the mechanism of the unique biological activities of aplog-1.
Assuntos
Toxinas de Lyngbya/química , Toxinas de Lyngbya/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Proteína Quinase C/metabolismo , Relação Estrutura-AtividadeRESUMO
A concise method for the synthesis of heterocycle-fused naphthoquinones such as naphtho[2,3-b]-furan-4,9-dione, 1H-benz[f]indole-4,9-dione, and naphtho[2,3-b]thiophene-4,9-dione was developed. This method employed Sonogashira coupling and tandem addition-elimination/intramolecular cyclization, and it enabled the preparation of versatile heterocycle-fused naphthoquinones from one substrate.
Assuntos
Naftoquinonas/química , Acetileno/química , Catálise , Ciclização , Naftoquinonas/síntese químicaRESUMO
Nine phenolic compounds, including two phenolic carboxylic acids, 1 and 2, seven hydrolyzable tannins, 3-9, eight triterpenoids, including four oleanane-type triterpene acids, 10-13, and four of their glucosides, 14-17, isolated from a MeOH extract of the gall of Terminalia chebula Retz. (myrobalan tree; Combretaceae), were evaluated for their inhibitory activities against melanogenesis in B16 melanoma cells induced by α-melanocyte-stimulating hormone (α-MSH), against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, and against TPA-induced inflammation in mice. Their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities and cytotoxic activities against four human cancer cell lines were also evaluated. Compounds 6-9 and 12 exhibited potent inhibitory activities against melanogenesis (39.3-66.3% melanin content) with low toxicity to the cells (74.5-105.9% cell viability) at a concentration of 10 µM. Western-blot analysis revealed that isoterchebulin (8) reduced the protein levels of MITF (=microphtalmia-associated transcription factor), tyrosinase, and TRP-1 (=tyrosine-related protein 1), mostly in a concentration-dependent manner. Eight triterpenoids, 10-17, showed potent inhibitory effects on EBV-EA induction with the IC50 values in the range of 269-363 mol ratio/32 pmol TPA, while these compounds exhibited no DPPH scavenging activities (IC50 >100 µM). On the other hand, the nine phenolic compounds, 1-9, exhibited potent radical-scavenging activities (IC50 1.4-10.9 µM) with weak inhibitory effects on EBV-EA induction (IC50 460-518 mol ratio/32 pmol TPA). The tannin 6 and seven triterpenoids, 10-16, have been shown to inhibit TPA-induced inflammation (1 µg/ear) in mice with the ID50 values in the range of 0.06-0.33 µmol/ear. Arjungenin (10) exhibited inhibitory effect on skin-tumor promotion in an in vivo two-stage mouse-skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator and with TPA as promoter. Compounds 1, 2, 4, 5, 7-9, 12, and 13, against HL60 cell line, compounds 1 and 4, against AZ521 cell line, and compounds 1, 11, and 12, against SK-BR-3 cell line, showed moderate cytotoxic activities (IC50 13.9-73.2 µM).