RESUMEN
A phytochemical investigation of the stems of Waltheria douradinha resulted in isolation of two 4-quinolone alkaloids, waltherione B and vanessine, along with three known alkaloids, waltherione A, antidesmone and O-methyltembamide. Their structures were elucidated on the basis of their 2D NMR spectroscopic analyses, and from X-ray crystallographic analysis of waltherione A and the O-methyl derivative of waltherione B. Additionally, waltherione B and vanessine, and the O- and N-methyl derivatives of waltherione A and waltherione B, were evaluated for their antimicrobial activities; only vanessine displayed any (weak) antimicrobial activity.
Asunto(s)
Alcaloides/química , Malvaceae/química , Extractos Vegetales/química , Quinolonas/química , Alcaloides/farmacología , Compuestos Aza/química , Compuestos Aza/farmacología , Bacterias/efectos de los fármacos , Cristalografía por Rayos X , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Extractos Vegetales/farmacología , Quinolinas/química , Quinolinas/farmacología , Quinolonas/farmacología , EstereoisomerismoRESUMEN
Investigation of the chemical constituents from the roots of Melochia chamaedrys (Sterculiaceae) resulted in the isolation of two quinolinone alkaloids: a new alkaloid, named chamaedrone (1), and a known alkaloid, antidesmone (2). Their structures and stereochemistry were elucidated on the basis of 2D NMR and X-ray crystallographic analysis. Furthermore, alkaloids 1 and 2, and the synthetic analogues 3-6 obtained from 2, were screened for antimicrobial activities.
