A novel kind of alkaloid was isolated from the aerial of Epimedium koreanum Naki. The molecular weight and molecular formula were achieved by FT-ICRMS as 370 128 5012 and C 20H 20O 6N. The molecular structure of the c...A novel kind of alkaloid was isolated from the aerial of Epimedium koreanum Naki. The molecular weight and molecular formula were achieved by FT-ICRMS as 370 128 5012 and C 20H 20O 6N. The molecular structure of the compound C 20H 20O 6N was determined on the basis of spectral analyses as 6-hydroxy-11,12-dimethoxy-2,2-dimethyl-1,8-dioxo-1,3,4,8-tetrahydro-2H-7-oxa-2-azonia-benzo phenanthene. Using electrospray ionization multi-stage mass spectrometry, the structure was confirmed further. The compound was first reported from this kind of plant.展开更多
Two kinds of saponins have been investigated by negative electrospray ionization(NESI) mass spectrometry. Under ESI conditions, the - ions of saponins were observed which provide the molecular weights of saponins. The...Two kinds of saponins have been investigated by negative electrospray ionization(NESI) mass spectrometry. Under ESI conditions, the - ions of saponins were observed which provide the molecular weights of saponins. The fragment pathways of - ions of these two saponins depend on their structures. For steroidic saponins, - ion only produces the fragment ions by the losses of sugar units. For oleanolic saponins, - ion yields the cross ring ions as well as the fragment ions by the losses of sugar units. Moreover, the abundance of the former is higher than that of the latter. The characteristic fragments are used to provide the sequence and some linkage information of sugar moieties of saponins. Especially, their fragment difference strongly depends on the linkage between the aglycone and the sugar moieties.展开更多
文摘A novel kind of alkaloid was isolated from the aerial of Epimedium koreanum Naki. The molecular weight and molecular formula were achieved by FT-ICRMS as 370 128 5012 and C 20H 20O 6N. The molecular structure of the compound C 20H 20O 6N was determined on the basis of spectral analyses as 6-hydroxy-11,12-dimethoxy-2,2-dimethyl-1,8-dioxo-1,3,4,8-tetrahydro-2H-7-oxa-2-azonia-benzo phenanthene. Using electrospray ionization multi-stage mass spectrometry, the structure was confirmed further. The compound was first reported from this kind of plant.
文摘Two kinds of saponins have been investigated by negative electrospray ionization(NESI) mass spectrometry. Under ESI conditions, the - ions of saponins were observed which provide the molecular weights of saponins. The fragment pathways of - ions of these two saponins depend on their structures. For steroidic saponins, - ion only produces the fragment ions by the losses of sugar units. For oleanolic saponins, - ion yields the cross ring ions as well as the fragment ions by the losses of sugar units. Moreover, the abundance of the former is higher than that of the latter. The characteristic fragments are used to provide the sequence and some linkage information of sugar moieties of saponins. Especially, their fragment difference strongly depends on the linkage between the aglycone and the sugar moieties.
