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).
