Department of Chemistry, Higher Teacher Training College , University of Yaoundé 1 , P.O. Box 47, Yaoundé , Cameroon.
Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstrasse 2 , D-37077 Göttingen , Germany.
J Nat Prod. 2018 May 25;81(5):1193-1202. doi: 10.1021/acs.jnatprod.7b00958. Epub 2018 Apr 17.
Three new alkaloids, janetinine (1a), pleiokomenine A (2), and huncaniterine B (3a), and 13 known compounds, pleiomutinine (3b), huncaniterine A (3c), 1-carbomethoxy-β-carboline (4), evoxanthine (5), deformyltalbotine acid lactone (6), pleiocarpamine (7), N-methyl-10-hydroxygeissoschizol (8), spegatrine (9), neosarpagine (10), aspidofractinine (11), N-methylkopsinin (12), pleiocarpine (13), and N-methylkopsinin- N-oxide (14), were isolated from the stem bark of Pleiocarpa pycnantha. Janetinine (1a) is a carbazole alkaloid; in pleiokomenine A (2), two aspidofractinine-type alkaloids are bridged by a methylene unit in an unprecedented way, and huncaniterine B (3a) is a pleiocarpamine-aspidofractinine-type dimer. The structures and relative configurations of these compounds were elucidated on the basis of NMR and MS analyses. Their absolute configurations were defined by means of experimental and calculated ECD data, and additionally, the structures of 5 and 13 were determined by single crystal X-ray diffraction. Compounds 1a, 2, 3b, 4, 6, 9, and 12 displayed cancer chemopreventive properties through either quinone reductase induction ( CD = 30.7, 30.2, 29.9, 43.5, and 36.7 μM for 1a, 4, 6, 9, and 12, respectively) and/or NF-κB inhibition with IC values of 13.1, 8.4, 9.4, and 8.8 μM for 2, 3b, 6, and 12, respectively.
从 Pleiocarpa pycnantha 的茎皮中分离得到三种新生物碱：janetinine（1a）、pleiokomenine A（2）和 huncaniterine B（3a），以及 13 种已知化合物：pleiomutinine（3b）、huncantiterine A（3c）、1-甲氧基-β-咔啉（4）、evoxanthine（5）、deformyltalbotine 酸内酯（6）、pleiocarpamine（7）、N-甲基-10-羟基-geissoschizol（8）、spegatrine（9）、neosarpagine（10）、aspidofractinine（11）、N-甲基 kopsinin（12）、pleiocarpine（13）和 N-甲基 kopsinin-N-氧化物（14）。Janetinine（1a）是一种咔唑生物碱；在 pleiokomenine A（2）中，两个 aspidofractinine 型生物碱通过亚甲基单元以一种前所未有的方式桥接，而 huncaniterine B（3a）是一种 pleiocarpamine-aspidofractinine 型二聚体。这些化合物的结构和相对构型是根据 NMR 和 MS 分析确定的。它们的绝对构型是通过实验和计算 ECD 数据来定义的，此外，化合物 5 和 13 的结构是通过单晶 X 射线衍射确定的。化合物 1a、2、3b、4、6、9 和 12 通过醌还原酶诱导（化合物 1a、4、6、9 和 12 的 CD 值分别为 30.7、30.2、29.9、43.5 和 36.7μM）和/或 NF-κB 抑制表现出抗癌预防特性，IC 值分别为 2、3b、6 和 12 的 13.1、8.4、9.4 和 8.8μM。
