Simultaneous determination of seven major isosteroidal alkaloids in bulbs of Fritillaria by gas chromatography.

The present paper describes the development of a most simple, sensitive, and specific gas chromatographic method to date, for the direct determination of seven major bioactive isosteroidal alkaloids, namely ebeiedine, ebeiedinone, ebeienine, hupehenine, isoverticine, verticine, verticinone and imperialine, in Fritillaria species, a commonly used antitussive traditional Chinese medicinal (TCM) herb. In the present study, a commercially available Supelco SAC-5 capillary column (30 m x 0.25 mm, 0.25 microm) specifically designed for the analysis of steroids was utilized for the direct determination of Fritillaria alkaloids. Calibration curves were obtained by spiking authentic compounds and the internal standard (solanidine) into herbal samples prior to extraction. Extraction was conducted simply by shaking the pre-alkalized diethyl ether solution (5.0 ml) containing dried herb (0.1 g) for 2 h. All calibration curves showed good linear regressions (r2>0.995) within test ranges. The assay was reproducible and accurate with the overall intra- and inter-day variation and accuracy of less than 10% and more than 90%, respectively. The developed GC method was successfully utilized to analyze seven major bioactive alkaloids in seven Fritillaria species, and the results demonstrate that this direct GC analytical method is suitable for the quality control of this commonly used antitussive TCM herb.