RESUMEN
Two new isocoumarin glucosides, haworforbins A (1) and B (2), and a new chromone, haworforbin C (3), have been isolated from Haworthia cymbiformis. Their structures and absolute configurations were elucidated on the basis of NMR and CD data. Haworforbin C (3) exhibited moderate inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cell line.
Asunto(s)
Glucósidos/química , Glucósidos/farmacología , Magnoliopsida/química , Fenoles/química , Fenoles/farmacología , Animales , Línea Celular , Lipopolisacáridos/farmacología , Espectroscopía de Resonancia Magnética , Ratones , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismoRESUMEN
Anti-melanogenesis screening of 47 synthesized curcumin-like diarylpentanoid analogues was performed to show that some had a potent inhibitory effect on the melanogenesis in B16 melanoma cells. Their actions were considered to be mostly due to tyrosinase inhibition, tyrosinase expression inhibition, and melanin pigment degradation. The structure-activity relationships of those curcumin-like diarylpentanoid analogues which inhibited the melanogenesis and tyrosinase activity were also discussed. Of those compounds assayed, (2E,6E)-2,6-bis(2,5-dimethoxybenzylidene)cyclohexanone showed the most potent anti-melanogenesis effect, the mechanism of which is considered to be the degradation of the melanin pigment in B16 melanoma cells, affecting neither the tyrosinase activity nor tyrosinase expression.
Asunto(s)
Curcumina/farmacología , Melaninas/metabolismo , Melanocitos/efectos de los fármacos , Melanoma Experimental/enzimología , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Curcumina/análogos & derivados , Curcumina/síntesis química , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Melanocitos/enzimología , Melanocitos/patología , Melanoma Experimental/patología , Ratones , Estructura Molecular , Monofenol Monooxigenasa/antagonistas & inhibidores , Monofenol Monooxigenasa/metabolismo , Relación Estructura-ActividadRESUMEN
In our screening program for bioactive natural products from our library of tropical plants, the extract prepared from the roots of Stemona javanica inhibited NO production in mouse macrophage-like cell line J774.1 stimulated by lipopolysaccharide (LPS). Bioassay-guided fractionation of the extract from S. javanica led to the isolation of two active compounds, stemofoline (1) and stemanthrene C (2). The inhibition mechanism of 1 was proposed to suppress iNOS expression in J774.1 cells stimulated by LPS, whereas that of 2 was due to potent radical scavenging activity resulting in NO inhibitory activity.