Use of on-flow LC/H-1 NMR for the study of an antioxidant fraction from Orophea enneandra and isolation of a polyacetylene, lignans, and a tocopherolderivative

The CH2Cl2 extract of the leaves of Orophea enneandra displayed antifungal, antioxidant, and radical scavenging properties in bioautographic TLC assay s. To obtain rapid information on the active compounds, on-flow LC/H-1 NMR and LC/UV/MS analyses of the antioxidant fraction were performed. The on-li ne information led rapidly to the partial identification of three closely r elated lignans, one tocopherol derivative, and one polyacetylene. This appr oach necessitated, however, large quantities to be injected to obtain satis factory on-flow LC/H-1 NMR spectra, and isolation of the compounds was nece ssary to obtain complete NMR data. These compounds were isolated and identi fied as (-)-phylligenin (1), (-)-eudesmin (2), (-)-epieudesmin (3), polycer asoidol (4), and oropheic acid (5), a new polyacetylene. Their activities a gainst the 2,2-diphenyl-1-picrylhydrazyl radical and the fungus Cladosporiu m cucumerinum were investigated. This paper indicates the possibilities and limits of on-flow LC/H-1 NMR in this type of study.