RESUMEN
Isovitexin exhibits potent antioxidant activities. In this study, the activity of nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-activated RAW264.7 macrophages after incubation with isovitexin was investigated. Isovitexin was able to reduce the production of hydrogen peroxide induced by LPS in mouse macrophage RAW264.7 cells. The cells incubated with isovitexin had markedly reduced LPS-stimulated NO production with an IC (50) value of 58.5 microM. The expression of iNOS was also inhibited when the cells were treated with isovitexin. A transient transfection experiment showed that isovitexin suppressed the iNOS promoter and NF-kappaB-dependent transcriptional activities. It was also found to inhibit IKK kinase activity and prevent the degradation of IkappaBalpha in activated RAW264.7 cells. Additionally, Western blotting analysis revealed that isovitexin prevented the translocation of NF-kappaB from the cytoplasm to the nucleus. Our results indicate that its ROS scavenger and IKK inhibitory activities also contribute to the suppression of ROS-mediated NF-kappaB activity. These results suggest that isovitexin, a food phytochemical contained in dietary rice products, might have biological significance.
Asunto(s)
Antioxidantes/farmacología , Apigenina/farmacología , FN-kappa B/metabolismo , Óxido Nítrico Sintasa/metabolismo , Oryza , Fitoterapia , Animales , Antioxidantes/administración & dosificación , Antioxidantes/uso terapéutico , Apigenina/administración & dosificación , Apigenina/uso terapéutico , Cartilla de ADN , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Citometría de Flujo , Lipopolisacáridos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
A series of bis-aziridinylnaphthoquinone derivatives has been prepared. The cytotoxic activities and DNA alkylation abilities of these synthetic bis-aziridinylnaphthoquinone derivatives were investigated. They displayed significant cytotoxicity against human carcinomna cell lines and weak cytotoxic activities against HL60 and skin fibroblast (SF). The bisaziridinylnaphthoquinone 1a was the most potent agent among those tested, with an LD50 value of 0.57 microM against the BC-M1 cell line. It exhibited the weakest activity against SF and HL60 with LD50 values of 5.67 and 20.1 microM, respectively, and it was able to alkylate DNA after chemical reduction in vitro. The analogues without aziridinyl moiety 2a and 3a lack DNA alkylation abilities.
Asunto(s)
Aziridinas/síntesis química , Aziridinas/toxicidad , Naftoquinonas/síntesis química , Naftoquinonas/toxicidad , Evaluación Preclínica de Medicamentos/métodos , Humanos , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/fisiologíaRESUMEN
The antioxidant properties of isovitexin and related flavonoids were studied. Isovitexin inhibited xanthine oxidase with an IC50 value of = 15.2 microM. The flavonoid analogues, apigenin, kaempferol, quercetin, myricetin, and genistein also inhibited xanthine oxidase with IC50 values of 0.58, 2.18, 1.09, 9.90, and 4.83 microM, respectively. Isovitexin protected DNA from the Fenton reaction-induced breakage in a dose-dependent manner with an IC50 value of 9.52 microM. Isovitexin also protected HL-60 cells from the ROS damage induced by the xanthine/xanthine oxidase reaction. Isovitexin exhibited the lowest cytotoxicity toward HL-60 cells (LD50 >400 microM) compared to the other flavonoids examined. In addition, excess hydrogen peroxide induced by cadmium in A2780 ovarian cells was significantly suppressed by isovitexin. These results suggest that isovitexin in rice may protect cells from oxidative stress.