GC-MS analysis of Amaryllidaceae and Scletium-type alkaloids in bioactive fractions from Narcissus cv. Hawera.

Rationale Narcissus cv. Hawera has been found to biosynthesize some Sceletium-type alkaloids with antidepressant and anxiolytic activities. This ornamental plant has been poorly studied as a source of bioactive alkaloids including some contraversive reports on in vitro and intact plants. Here, a detailed GC-MS characterization of its alkaloid fractions is presented. Methods GC-MS was used for identification of compounds in the alkaloid fractions. Both, underivatized and silylated samples were analyzed in parallel. Elevated plus maze and tail suspension tests were used to assay the anxiolytic and antidepressant activities. Ellman's and MTT-dye reduction assays were used to evaluate the AChE inhibitory and cytotoxicity activities, respectively. Results Twenty-nine alkaloids, 13 of them of Sceletium-type were detected. Two new alkaloids were identified as 2-oxo-mesembrine and 2-oxo-epi-mesembrenol. Lycorine was found as a major compound (43.5%) in the crude silylated methanol extract. After elimination of lycorine by pre-crystallization, the major alkaloids were 40.8% 6-epi-mesembranol, 16.2% 6-epi-mesembrenol, and 13.8% sanguinine. This fraction showed anxiolytic and antidepressant-like activities as well as potent AChE inhibitory and antineoplastic activities. Conclusions Silylation of the alkaloid fractions from Narcissus cv. Hawera provides better separation, structural information and improved sensitivity for compounds with two and more hydroxyl groups. The lycorine-free alkaloid fraction shows a great potential for further pharmacological studies.