P-11 ユズリハ科植物由来の新規アルカロイドcalyciphylline C〜Gの構造と生物活性(ポスター発表の部)

概要

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Daphniphyllum alkaloids are a structually diverse group of natural products with unique fused-heterocyclic skeletons, which are elaborated by trees of the genus Daphniphyllum (Daphniphyllaceae). These unusual ring systems have been challenging targets for total synthesis as well as biosynthetic studies. We have isolated novel types of Daphniphyllum alkaloids from Daphniphyllum macropodum, D. humile, D. teijsmanni, and D. glaucescense. In our continuing search for structually unique and biogenetically interesting new alkaloids, calyciphyllines C-G (1-5) have been isolated from D. calycinum, and their structures and relative stereochemistry were elucidated on the basis of spectroscopic data. Calyciphylline C (1) is a novel Daphniphyllum alkaloid with an unprecedented fused-hexacyclic skeleton having an azetidine ring. Calyciphyllines D (2) and F (4) are novel alkaloids containing a unique fused-pentacyclic skeleton with a 8-azatricyclo[4.2.1.0.^<4,8>]nonane ring system. Calyciphylline E (3) is a new alkaloid with a fused-heptacyclic ring system, while calyciphylline G (5) is a novel alkaloid possessing an unprecedented fused-hexacyclic skeleton containg 5-azatricyclo[6.2.1.0]undecane ring system. Effects of these alkaloids on neurotrophic factor biosynthesis in 1321N1 human astrocytoma cells were examined by a semiquantitative RT-PCR method to find that the mRNA expressions for NGF were enhanced.
2007-08-24