Rapid differentiation of Schisandra sphenanthera and Schisandra chinensis by matrix-assisted laser desorption/ionization mass spectrometry

Schisandrae sphenanthera (S. sphenanthera, southern magnoliavine fruit, Nan-Wuweizi) and Schisandrae chinensis (S. chinensis, northern magnoliavine fruit, Bei-Wuweizi) belong to Fructus Schisandrae (Wuweizi), and are commonly used herbal medicines. The quality of S. chinensis is believed to be superior to that of S. sphenanthera. In this study, a matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS)-based approach has been developed and demonstrated for rapid differentiation of S. sphenanthera and S. chinensis for the first time. The MALDI-MS spectra acquired with a brief extraction of the samples showed significantly different patterns for the two species. S. sphenanthera and S. chinensis could be unambiguously differentiated based on detection of the specific compounds (e.g., schisandrin at m/z 432 for S. chinensis and schisantherin A at m/z 575 for S. sphenanthera), intensity ratios of characteristic peaks (e.g., m/z 416 vs. m/z 415 and m/z 138 vs. m/z 136), and principal component analysis of the spectra. Direct analysis of the herbal powders by MALDI-MS could also allow differentiation of S. sphenanthera and S. chinensis. These approaches are rapid, simple, robust, and can be used for high throughput analysis of S. sphenanthera and S. chinensis.