A New Lycopodine-type Alkaloid from Lycopodium japonicum

Abstract A new lycopodine-type alkaloid, 12β-hydroxy-acetylfawcettiine N-oxide (1), together with seven known analogues, acetyllycoposerramine M (2), lycopodine (3), lycoclavine (4), diphaladine A (5), lycoposerramine K (6), 11β-hydroxy-12-epilycodoline (7) and fawcettiine (8), were isolated from Lycopodium japonicum. Their structures were established by mass spectrometry and 1D and 2D NMR techniques. The isolated alkaloids were assayed for their inhibition activities against acetylcholinesterase, but no inhibitory activities for the compounds were detected.

The isolated alkaloids were assessed for their inhibition on acetylcholinesterase by the improved ellman's method (ellman et al. 1961), and the result showed that none of them displayed significant inhibitory activity.

Apparatus and reagents
eSI-MS and HR-eSI-MS spectra were obtained from a Vg Auto Spec-3000 spectrometer. IR spectra were recorded on a Bio-Rad FTS-135 polarimeter. UV spectra were measured on a UV-24021PC spectrometer. Optical rotations were determined on a Horiba SeAP-300 spectropolarimeter. NMR spectra were acquired using a Bruker Avance-500 spectrometer, using TMS as an internal standard. Column chromatography was carried out on silica gel H (Qingdao Haiyang Chemical Factory, Qingdao, China) and Sephadex LH-20 (25-100 μm, Pharmacia Fine Chemical Co. Ltd, Uppsala, Sweden). TLC was performed on silica gel gF 254 (Yantai Jiangyou Silica gel Co. Ltd, Yantai, China). Solvents were of industrial purity and distilled prior to use.

Plant material
L. japonicum was collected from Malipo of Yunnan Province, China in July 2014 and identified by Prof. Shugang Lu, School of Life Science, Yunnan University, Kunming, China, where a voucher specimen (No. 1407001) is deposited.

Disclosure statement
No potential conflict of interest was reported by the authors.

Funding
This work was supported by the Natural Science Foundation of China [grant number 21162045]; Yunnan Province of China for basic research in social development [grant number 2009CC018].