RESUMO
Trans-dehydrocrotonin has antiulcerogenic and antitumor activities. A complex of beta-cyclodextrin with dehydrocrotonin was developed to improve the delivery of dehydrocrotonin. Complex in solid state was evaluated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). X-ray diffraction and scanning electron microscopy studies showed that dehydrocrotonin exists in a semicrystalline state in the complexed form with beta-cyclodextrin. Differential scanning calorimetry studies showed the existence of a complex of dehydrocrotonin with beta-cyclodextrin. The thermal gravimetric analysis studies confirmed the differential scanning calorimetry results of the complex. Free dehydrocrotonin and the dehydrocrotonin/beta-cyclodextrin inclusion complex were assayed in freshly isolated rat hepatocytes and in V79 cells. Cytotoxicity was determined using nucleic acid content, methylthiazoletetrazolium (MTT) reduction and neutral red uptake assays. In all assays, there was a large reduction (3.5-16.1-fold) in the cytotoxicity of dehydrocrotonin in hepatocytes when complexed with beta-cyclodextrin, whereas for V79 cells the decrease in cytotoxicity was 1.7- and 1.87-fold for MTT reduction and nucleic acid content assays, respectively. The lower cytotoxicity of the dehydrocrotonin/beta-cyclodextrin complex compared to free dehydrocrotonin in rat hepatocytes and V79 cells suggests that such a complex may be useful for the administration of dehydrocrotonin in vivo.
Assuntos
Diterpenos Clerodânicos/farmacologia , Fibroblastos/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , beta-Ciclodextrinas/farmacologia , Animais , Varredura Diferencial de Calorimetria , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Diterpenos Clerodânicos/química , Relação Dose-Resposta a Droga , Fibroblastos/citologia , Fibroblastos/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Concentração Inibidora 50 , Masculino , Microscopia Eletrônica de Varredura , Ácidos Nucleicos/metabolismo , Ratos , Ratos Wistar , Termogravimetria , Difração de Raios X , beta-Ciclodextrinas/químicaRESUMO
The effects of beta-cyclodextrin (betaCD) inclusion complexation on the ability of violacein to prevent gastric ulceration in mice were studied. Violacein-betaCD inclusion complexes were prepared in 1:1 and 1:2 molar ratios and analysed by differential scanning calorimetry and powder X-ray diffractometry. Violacein previously administered orally at 10 mg/kg significantly reduced indomethacin-induced gastric lesions, as well as 100 mg/kg of cimetidine (positive control). However, betaCD complexation in both molar ratios significantly potentiated the protective action of violacein. In the HCl--ethanol-induced gastric ulcer model, violacein and the 1:2 inclusion complex (10 mg/kg, p.o.) inhibited gastric damage by almost 85%, whereas a 63% reduction was observed for the positive control, lansoprazole, at 30 mg/kg. In contrast, treatment with the 1:1 inclusion complex resulted in almost total disappearance of the antiulcer activity in this model. No significant changes in stress-induced gastric injury were found. In addition, the 1:2 inclusion complex improved the antilipoperoxidant activity of violacein in rat liver cells exposed to t-butyl hydroperoxide, whereas the 1:1 complex was less active than violacein. In summary, the 1:2 betaCD inclusion complex has gastroprotective properties similar to or higher than that of violacein. An increase in mucosal defensive mechanisms and protection against peroxidative damage might be involved.
Assuntos
Antiulcerosos/farmacologia , Ciclodextrinas/farmacologia , Indóis/farmacologia , Animais , Células Cultivadas , Química Farmacêutica , Cimetidina/farmacologia , Modelos Animais de Doenças , Etanol/efeitos adversos , Hepatócitos/efeitos dos fármacos , Ácido Clorídrico/efeitos adversos , Indometacina/efeitos adversos , Indometacina/antagonistas & inibidores , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Camundongos , Ratos , Ratos Wistar , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/tratamento farmacológico , Úlcera Gástrica/prevenção & controle , Estresse Fisiológico/fisiopatologia , terc-Butil Hidroperóxido/efeitos adversosRESUMO
Violacein, a pigment isolated from Chromobacterium violaceum, has been reported to have multiple biological activities including in vitro antitumor effects. Certain anticancer agents are known to induce apoptosis in human tumor cell lines. In this work, our aim was to investigate the effectiveness of violacein/beta-cyclodextrin (beta-CD)-containing systems to produce lethal effects in the human promyelocytic leukemia cell line HL60. Using the MTT tetrazolium reduction test, IC(50) for the inclusion complexes (1:1 and 1:2 violacein:beta-CD molar ratios) and violacein alone were less than 1 microM. Violacein and violacein/beta-CD complexes were able to induce NBT reduction. Moreover, by using the Feulgen reaction, all the compounds were found to trigger apoptosis in HL60 cells, inducing around 35% of DNA fragmentation, as analyzed through the diphenylamine assay. In addition, caspases seem to play an important role in the activation of the executioner phase of apoptosis induced by violacein and its derivatives.