Abstract: The bark of Magnolia officinalis is a well-known Traditional Chinese Medicine. In the present study, two new alkaloids, named (S)-4-keto-magnoflorine (6) and (R)-3,4-dehydromagnocurarine (11), together with seven known alkaloids: (S)-magnoflorine (5), trans/cis N-feruloylputrescine (7/8), (R)-magnocurarine (10), (S)-tembetarine (12), (R)-oblongine (14), and (R)-asimilobine (17) were isolated and their structures elucidated by spectroscopic methods, including 1D, 2D NMR, and HRESI-MS. The absolute configurations of the isoquinoline alkaloids 5, 6, 10–12, 14, and 17 were determined by CD. In vitro inhibitory activities against aldose reductase, lipase, α-glucosidase, DPP–IV and three cancer cell lines (A549, Bel-7402, and HCT-8) were evaluated for all isolated compounds. However, all compounds showed weak activities in all tests at the same concentration as the positive control drugs. An HPLC-ESI-MSn method has been established for screening of alkaloids in the bark of M. officinalis. A total of 23 alkaloids were identified or tentatively characterized; including 13 aporphines, eight benzylisoquinolines and two amides. Plausible fragmentation pathways of the representative compounds 6, 7/8, 11, and 17 were proposed in the present study.
This is an open access article distributed under the
Creative Commons Attribution License which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Export to BibTeX
MDPI and ACS Style
Yan, R.; Wang, W.; Guo, J.; Liu, H.; Zhang, J.; Yang, B. Studies on the Alkaloids of the Bark of Magnolia officinalis: Isolation and On-line Analysis by HPLC-ESI-MSn. Molecules 2013, 18, 7739-7750.
Yan R, Wang W, Guo J, Liu H, Zhang J, Yang B. Studies on the Alkaloids of the Bark of Magnolia officinalis: Isolation and On-line Analysis by HPLC-ESI-MSn. Molecules. 2013; 18(7):7739-7750.
Yan, Renyi; Wang, Weihao; Guo, Jian; Liu, Hongliang; Zhang, Jianyong; Yang, Bin. 2013. "Studies on the Alkaloids of the Bark of Magnolia officinalis: Isolation and On-line Analysis by HPLC-ESI-MSn." Molecules 18, no. 7: 7739-7750.