Title
Alkaloids from the stems of Clausena lansium and their neuroprotective activity
Author
Jie Liu, Yi-Qian Du, Chuang-Jun Li, Li Li, Fang-You Chen, Jing-Zhi Yang, Nai-Hong Chen, Dong-Ming Zhang
Year
2017
Journal
RSC Advances
Abstract
ight new alkaloids, including three pairs of enantiomers (+)-(2′S,3′R)-clauselansine A (1a) and (−)-(2′R,3′S)-clauselansine A (1b); (+)-(2′S,3′R)-clauselansine B (2a) and (−)-(2′R,3′S)-clauselansine B (2b); (+)-(3S,4R,5S,6S)-clauselansine C (3a) and (−)-(3R,4S,5R,6R)-clauselansine C (3b), (+)-(1′R,2′R,6′R)-claulansine B (4a), and (+)-(1′R,2′R)-claulansine D (5a), together with twelve known alkaloids (4b, 5b, 6a, 6b, 7a, 7b and 8–13) were isolated from the stems of Clausena lansium. Their structural elucidation and stereochemistry determination were achieved by spectroscopic and chemical methods including 1D and 2D NMR experiments, especially the employment of electronic circular dichroism calculation spectra, Mosher's method, and Snatzke's method expressed by the induced circular dichroism spectrum. Compounds 1b, 2a, 3b, 5a, and 5b inhibited PC12 cell damage induced by Okadaic Acid, and increased cell viability from 70.5 ± 5.4% to 83.4 ± 4.1%, 91.2 ± 10.1%, 83.5 ± 7.8%, 89.7 ± 4.8%, 83.3 ± 5.9% at 10 μM, respectively.
Instrument
J-815
Keywords
Circular dichroism, Absolute configuration, Natural products, Medicinal