 PERGAMON Phytochemistry 49 "0888# 892Ð896 9920!8311:88:, ! see front matter Þ 0888 Elsevier Science Ltd[ All rights reserved[ PII]S9920!8311"87#99501!7 Bishordeninyl terpene alkaloids from Zanthoxylum avicennae Trinh Thi Thuy a \ Andrea Porzel b \ Helmut Ripperger b \ Tran Van Sung a \ Gu  nter Adam b\  a Institute of Chemistry\ National Centre for Natural Science and Technology of Vietnam\ Nghia Do\ Tu Liem\ Hanoi\ Vietnam b Institute of Plant Biochemistry\ Weinberg 2\ 95019 Halle "Saale#\ Germany Received 02 February 0887 Abstract In addition to "−#!culantraramine and "−#!culantraraminol the bishordeninyl terpene alkaloids\ "−#!culantraramine N!oxide\ "−#!culantraraminol N!oxide and avicennamine\ have been isolated from the leaves of Zanthoxylum avicennae[ Their structures have been assigned by MS and especially by NMR investigations[ Þ 0888 Elsevier Science Ltd[ All rights reserved[ Keywords] Zanthoxylum avicennae^ Rutaceae^ Bishordeninyl terpene alkaloids^ "−#!Culantraramine^ "−#!Culantraraminol^ "−#!Culantraramine N! oxide^ "−#!Culantraraminol N!oxide^ Avicennamine 0[ Introduction Zanthoxylum avicennae DC "Rutaceae# is an 7 m high shrub "Pham!hoang Ho\ 0881# growing in North and South Vietnam\ Cambodia and Laos "Do Tat Loi\ 0880#[ A decoction of its stems is used as a stomach tonic and as a counter!poison to snake bite "Perry\ 0879#[ Previous investigations have shown that the plant contains alkaloids "Fish\ Gray\ + Waterman\ 0864^ Wenzhu Wu + Zonghong Zhu\ 0881^ Miao Zhenchun\ Wu Wenzhu\ + Feng Rui\ 0882#\ terpenoids "Shifa Cheng\ Liangfeng Zhu\ Biyao Lu\ Yuexin Yu\ + Zhujin Liu\ 0889#\ ~avonoids "Fish et al[\ 0864# and coumarins "Fish et al[\ 0864^ Gray\ Waigh\ + Waterman\ 0864#[ In continuation of our phytochemical studies on Vietnamese plants "Nguyen Hoang Anh\ Ripperger\ Porzel\ Tran Van Sung\ + Adam\ 0886# we have isolated from the leaves of this species the optically active bishordeninyl terpene alka! loids "−#!culantraramine "0# and "−#!culantraraminol "3#\ hitherto only known as the racemates "Schroeder + Stermitz\ 0874#\ and the new alkaloids "−#!culantra! ramine N!oxide "mixture of 1¦2#\ "−#!culantra! raminol N!oxide "mixture of 4¦5# and avicennamine "6#\ the structures of which have been elucidated as outlined in Section 1[ 1[ Results and discussion The alkaloids were obtained from the methanol extract of the leaves via partition between chloroform and water  Corresponding author[ Tel[] ¦38!234!4471!105^ fax] ¦38!234!4471! 091^ e!mail] gadamÝibp[uni!halle[de and subsequent chromatographic procedures[ Column chromatography on silica gel a}orded _rstly "−#!cul! antraramine "0# and "−#!culantraraminol "3#\ identi_ed by comparison of the NMR data with those of their known racemates "Schroeder + Stermitz\ 0874#[ As expected for N!oxides the electron!impact mass spectra of the further constituents "−#!culantraramine N!oxide "mixture of 1¦2# and "−#!culantraraminol N!oxide "mixture of 4¦5# displayed ðMÐOŁ ¦ ions "C 21 H 35 N 1 O 1 and C 21 H 37 N 1 O 2 \ respectively#[ The electrospray ion! ization mass spectra showed quasi!molecular ions ðM¦HŁ ¦ [ The NMR signals of the compounds "Tables 0 and 1# as well as their structures were assigned on the basis of their gradient!selected HSQC\ 0 HÐ 0 H COSY "in the case of 1¦2 long!range#\ gradient!selected HMBC and NOESY spectra[ The data corresponded to those of culantraramine and culantraraminol "Schroeder + Stermitz\ 0874#[ C!2 to C!4 were not correctly assigned by Schroeder + Stermitz "0874#[ The signals for H!7? and H!8? Table 0 of the alkaloids 1\ 2\ 4 and 5 showed low!_eld shifts in comparison with those of compound 6 indicating protonation "Schroeder + Stermitz\ 0874# due to acidity in the CDCl 2 [ Some of the 02 C signals appeared twice "especially for C!0\ C!1\ C!1? and C!1ý# indicating a mixture of two regioisomeric compounds[ The elemental composition of avicennamine "6# was shown to be C 21 H 37 N 1 O 2 by high!resolution mass spec! trometry[ The constitution followed from the gradient! selected HSQC\ 0 HÐ 0 H COSY and gradient!selected HMBC spectra[ Tables 0Ð1 contain the 0 H and 02 C NMR data[ The relative con_guration was elucidated by NOESY spectroscopy "Fig[ 0#[ A cis!relationship of the