Metabolic profiling of bioactive Pancratium canariense extracts by GC-MS

Introduction - Pancratium canariense Ker Gawler is a plant species belonging to family Amaryllidaceae. Plants from this family are known to synthesise a particular type of bioactive compounds, named Amaryllidaceae alkaloids, which have shown AChE inhibitory activity.Objective - To perform the metabolite profiling of methanolic extracts from P. canariense in order to identify bioactive compounds.Methodology - Methanolic extracts from bulbs, leaves and fruits were separated into alkaloid-free apolar and polar fractions, as well as alkaloid fractions, and subjected to AChE assay. Metabolite profiling of extracts and fractions of P. canariense was carried out by GC-EI-MS and LC-ESI-TOF-MS.Results - AChE inhibitory activities of the alkaloid fractions at a concentration of 10 μg/mL were 29.80 ± 0.91, 40.93 ± 4.60 and 58.06 ± 1.18% for the bulbs, leaves and fruits, respectively. Seventy-six metabolites--mono-, di- and trisaccharides, fatty acids, amino acids, sterols as well as several Amaryllidaceae alkaloids--were detected. Further purification of the alkaloids from the methanolic extracts resulted in the detection of 31 compounds including several potent AChE inhibitors such as habranthine and galanthamine, and the structural elucidation of 3-O-acetylhabranthine, a new natural compound with potential AChE inhibitory activity.Conclusion - The described method resulted in effective integration of both GC-EI-MS and LC-ESI-TOF-MS strategies, which permitted the identification of many metabolites, as well as the structural elucidation of new compounds with potential AChE inhibitory activity. Copyright © 2009 John Wiley & Sons, Ltd.