Ma Onur

Alkaloids of Galanthus elwesii

Abstract Six new lycorenine-type alkaloids, (+)-5-methoxy-9- O -demethylhomolycorine, (+)-galwesine, (+)-9- O -demethylgalwesine, (+)-16-hydroxygalwesine, (+)-16-hydroxy-9- O -demethylgalwesine and galasine, were isolated from whole plants of Galanthus elwesii . Additionally, 12 known alkaloids, (−)-galanthamine, (−)-sanguinine, (−)-leucotamine, (−)- O -methylleucotamine, (±)-narwedine, (−)- N -demethylgalanthamine, (+)-11-hydroxyvittatine, (+)-9- O -demethylhomolycorine, (−)-lycorine, (−)-galanthine, hordenine, and ( E )- N -feruloyltyramine were also obtained. Of these alkaloids, only galanthamine and lycorine have been isolated previously from G. elwesii . Identification and structural elucidation were achieved using spectrometric techniques.

Nitrogen inversion in 9-O-Demethylhomolycorine

Abstract (+)-9- O -Demethylhomolycorine, which has been isolated from Galanthus elwesii , belongs to Amaryllidaceae alkaloids. From five different subfractions five different crystalline samples were observed, all their spectra are superimposible with each other. Two of them, 1b and 1c , differ in the configuration at the N-atom. The other samples differ by changing solvent content in crystals.

GC-MS Investigation and Acetylcholinesterase Inhibitory Activity of Galanthus rizehensis

GC-MS (gas chromatography-mass spectrometry) analyses of alkaloids in the aerial parts and bulbs of Galanthus rizehensis Stern (Amaryllidaceae), collected during two different vegetation periods, was performed. Twenty three alkaloids were identified in four different alkaloid extracts. Acetylcholinesterase (AChE) inhibitory activities of the alkaloid extracts were tested. Both the highest alkaloid diversity and the most potent inhibitory activity (IC50 12.94 μg/ml) were obtained in extracts from the bulbs of G. rizehensis collected during the fruiting period.

(±)-Corysolidine, a spirobenzylisoquinoline alkaloid from Corydalis solida

Abstract The whole plant of Corydalis solida , of Turkish origin, furnished (−)-corpaine as well as the new spirobenzylisoquinoline (±)-corysolidine.