Rapid screening of lignans from Phyllanthus myrtifolius and stilbenoids from Syagrus romanzoffiana by HPLC-SPE-NMR

Introduction – Application of on‐line solid‐phase extraction (SPE) as an interface between HPLC and NMR has gained great improvement in solving sensitivity problems and signal interferences by the eluents. Objective – Rapid analysis and characterisation by HPLC‐SPE‐NMR and LC/MS of the arylnaphthalene‐type lignans present in Phyllanthus myrtifolius and the minor stilbenoids present in the polyphenol‐rich fraction from the ethanol extract of the seeds of Syagrus romanzoffiana. Methodology – Pretreatment of fractions by liquid–liquid partitioning, followed by Sephadex LH‐20 fractionation, was found very useful to facilitate the focusing and analysis of the polyphenolic fraction. HPLC‐DAD‐SPE‐NMR (400 MHz and 600 MHz) analysis was carried out using an Agilent 1100 liquid chromatography, followed by a Prospekt 2 automated solid‐phase extraction unit, containing 96 HySphere‐Resin GP cartridges (10 × 2 mm, 10–12 µm), which was connected to a 120 or 60 µL LC probe. Results – Seven arylnaphthalene‐type lignans from the chloroform‐soluble fraction of P. myrtifolius and nine stilbenoids from a polyphenol‐rich butanol‐soluble fraction of the seeds of S. romanzoffiana were characterised. Conclusion – HPLC‐SPE‐NMR associated with HR‐ESI/MS, which consumed only analytical amounts of partially purified mixtures, was demonstrated to be a good tool for rapid screening of both known and new natural products. Copyright © 2011 John Wiley & Sons, Ltd.