RESUMEN
The active fraction extracted from dragon's blood displayed an inhibitory effect on alpha-glucosidase activity with an IC50 of 0.152 microg/mL, which is nearly half of the crude material. Its inhibition on alpha-glucosidase was noncompetitive. In addition, when this fraction was orally administered to mice dosed with Acarbose (20 mg/kg), the active fraction (100, 300, 500 mg/kg) significantly suppressed increase of blood glucose levels after sucrose loading in a dose-dependent manner. These results suggest that this extract from dragon's blood exerts an anti-diabetic effect by suppressing intestinal carbohydrate absorption and thereby reducing the postprandial increase of blood glucose.
Asunto(s)
Diabetes Mellitus Experimental/tratamiento farmacológico , Dracaena/química , Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes/aislamiento & purificación , Extractos Vegetales/uso terapéutico , Acarbosa , Animales , Glucemia/efectos de los fármacos , Metabolismo de los Hidratos de Carbono/efectos de los fármacos , Diabetes Mellitus Experimental/inducido químicamente , Inhibidores Enzimáticos/uso terapéutico , Absorción Intestinal , RatonesRESUMEN
In the present study, the intracellular free calcium concentration ([Ca(2+)](i)) in acutely isolated rat dorsal root ganglia (DRG) neurons modulated by loureirin B, an active component of "dragon's blood" which is a kind of Chinese herbal medicine, was determined by the means of Fura-2 based microfluorimetry. It was found that loureirin B could evoke the elevation of [Ca(2+)](i) in a dose-dependent manner. However, the elevation of [Ca(2+)](i) evoked in the calcium free solution was much smaller than that in the standard external cell solution, suggesting that most change of [Ca(2+)](i) was generated by the influx of extracellular Ca(2+), not by the activities of intracellular organelles like Ca(2+) stores and mitochondria. In addition, the mixture of loureirin B and caffeine also induced [Ca(2+)](i) rise, but the peak of [Ca(2+)](i) rise induced by the mixture was significantly lower than that by caffeine alone, which means the triggering pathway and the targets of caffeine are probably involved in loureirin B-induced [Ca(2+)](i) rise. Moreover, compared to the transients induced by caffeine, KCl and capsaicin, the loureirin B-induced [Ca(2+)](i) rise is much slower and more stable. These results indicate that the capability of loureirin B of inducing the [Ca(2+)](i) rise is solid and unique.
Asunto(s)
Calcio/metabolismo , Neuronas Aferentes/efectos de los fármacos , Resinas de Plantas/farmacología , Animales , Cafeína/farmacología , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/metabolismo , Neuronas Aferentes/metabolismo , RatasRESUMEN
A new dihydrochalcone, 4'-hydroxy-4,2'-dimethoxy-dihydrochalcone, was isolated from Chinese dragon's blood, the red resin of Dracaena cochinchinensis. Its structure was established by spectrum analysis.
Asunto(s)
Chalconas/aislamiento & purificación , Dracaena/química , Plantas Medicinales/química , Chalconas/química , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Resinas de Plantas/químicaRESUMEN
A novel practical binary vector to get marker-free transgenic plant was constructed. The estrogen-inducible Cre/loxP DNA recombination system was adopted in this system. All non-target genes located between two identical orientation loxP sites could be excised from the transgenic genome by the Cre expression. In order to analyze this system, the target gene, GUS expression box (CaMV35s: :GUS), was inserted in the MCS outside the region franked by two loxP sites. Then it was introduced into the tobaccos. Results showed that the high-efficiency DNA recombination had take place and the target gene was working order after DNA excitation.