Analysis of galanthamine and related alkaloids in plant extracts and during the purification process by GC-MS

Recently, GC-MS has been applied for the search and quantification of galanthamine in plant samples [1, 2] but not for monitoring of the extraction process and the active substance which is the aim of the present work.

Ten alkaloids were detected in the samples (A and B – plant extracts of Leucojum aestivum L., C and D – products of galanthamine purification). Eight of them were identified by comparing their MS and Kovats retention indexes (RI, HP-5 MS column) with those of authentic compounds isolated in our laboratory. Compound 6 was identified by NIST 05 database and 2 (galanthamine type) was left unidentified. GC-MS provided rapid information on the ratio of the alkaloids in the plant extracts, reliable identification of the impurities which are at trace amounts (<0.1% of TIC) in the active substance (sample D) and structural information on the unidentified compounds. The presence of 2 (0.1%) which co-eluted in the peak tail of 1 was unequivocally confirmed after deconvolution of its MS by AMDIS® 2.64 (NIST).

The combination of GC-MS, RI and mass spectral deconvolution is a powerful tool, providing a high specificity for the analysis of impurities at trace amounts and identification of co-eluted compounds with chemical structures similar to galanthamine.

Compound	RI	A	B	C	D
Galanthamine (1)	2405	65.71	74.94	94.41	99.78
A (2)	2422		1.8	0.05	0.1
N-Demethylgalanthamine (3)	2440	0.15	11.16	4.6	0.02
Epigalanthamine (4)	2450		0.13	0.02	0.02
Narwedine (5)	2479	1.47	3.76	0.88	0.04
Anhydrolycorine (6)	2501	0.53	0.34
Demethylmaritidine (7)	2507		1.25
N-Allylnorgalanthamine (8)	2540		0.06	0.02
Lycorine (9)	2746	31.91	5.09
N-Formylnorgalanthamine (10)	2812	0.24	1.49
Nonalkaloid compound	2548			0.02	0.02
Nonalkaloid compound	2827				0.02

Acknowledgements This work was partially financed by the Generalitat de Catalunya (2005SGR-00020). S. Berkov thanks the Spanish Ministerio de Educación y Ciencia for a research fellowship (SB2004–0062). The authors thank Galen-N Ltd (Bulgaria) for the provided samples.

References: [1] Gotti, R. et al. (2006) J Pharm Biomed Anal 42: 17–24. [2] Berkov, S. et al. (2007) Phytochem Anal (in press).