RESUMO
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.
Assuntos
Glucosídeos/química , Glucosídeos/farmacologia , Magnoliopsida/química , Fenóis/química , Fenóis/farmacologia , Animais , Linhagem Celular , Lipopolissacarídeos/farmacologia , Espectroscopia de Ressonância Magnética , Camundongos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismoRESUMO
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.
Assuntos
Curcumina/farmacologia , Melaninas/metabolismo , Melanócitos/efeitos dos fármacos , Melanoma Experimental/enzimologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Curcumina/análogos & derivados , Curcumina/síntese química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Melanócitos/enzimologia , Melanócitos/patologia , Melanoma Experimental/patologia , Camundongos , Estrutura Molecular , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Relação Estrutura-AtividadeRESUMO
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.