66(P35) コウゾ(Broussonetia kazinoki SIEB.)から得られる新ピロリジンアルカロイドbroussonetine G,H,I,J,K,Lの構造(ポスター発表の部)

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We reported the structures of six pyrrolidine alkaloids, broussonetine A-F, as glycosidase inhibitors from Broussonetia kazinoki SIEB. (Moraceae) in 37th symposium (Tokushima). In our continuing works, we obtained six new pyrrolidine alkaloids called broussonetines G (1), H (2), I (3), J (4), K (5) and L (6) from the same tree. The present report deals with the isolation, structural elucidation and inhibitory activity to some glycosidases. Broussonetines G-L were obtained from hot water extracts by ion exchange chromatography [Amberlite CG-50 (H^+ form), DOWEX 50W X4 (pretreated with 0.2M HCOONH_4 buffer)], SiO2 chromatography and reverse phase HPLC. The planar structures of 1-6 were determined by spectroscopic analysis, including two dementional NMR techniques. The relative stereostructure was elucidated based on NOESY spectrum. The absolute stereostructure of 3 and 4 were confirmed by the application of benzoate rule to the 3, 4-dihydroxyl pyrrolidine ring and a new version of Mosher's method to the C-3". Further studies of the absolute configulations of 1, 2, 5, 6 are now in progress. Compounds 1, 2, 5, 6 inhibited β-glucosidase, β-galactosidase, β-mannosidase. Broussonetines E and F, having a hydroxy group on C-1', inhibited α-glucosidase, but 1, 2, 5, 6 did not inhibit α-glucosidase, in spite of the presense of the same group.
天然有機化合物討論会の論文
1998-08-31