| Co-Investigator(Kenkyū-buntansha) |
UMEYAMA Akemi TOKUSHIMA BUNRI UNIVERSITY,FACULTY OF PHARMACEUTICAL SCI., ASSISTANT, 薬学部, 助手 (40160329)
YOSHIKAWA Kazuko TOKUSHIMA BUNRI UNIVERSITY,FACULTY OF PHARMACEUTICAL SCI., ASSISTANT, 薬学部, 助手 (40166921)
SYOUJI Noboru TOKUSHIMA BUNRI UNIVERSITY,FACULTY OF PHARMACEUTICAL SCI., ASSISTANT PROF., 薬学部, 助教授 (50109732)
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| Research Abstract |
1 ISOLATION OF ANTISWEET SUBSTANCES,STRUCTURE ELUCIDATON AND ANTISWEET ACTIVITIES
The EtOH extract obtained from the fresh stem of Stephanotis lutchuensis KOIDZ.var.Japonica was subjected to Amberlite XAD-2 column chromatography to give a saponin fraction. Repeated separation of the saponin fraction by gel filtration of Sephadex LH-20 and C_<18>-HPLC gave ten new compounds named sitakisosides XI,XII,XIII,XIV,XV,XVI,XVII,XVIII,XIX,and XX.Their structures were determined on the basis of spectroscopic data, acid hydrolysis and alkaline hydrolysis. The results show that all have a 3-O-beta-D-xylopyranosyl(1*6)-beta-D-glucopyranosyl(1*6)-beta-D-glucopyranosyl moiety and the aglycones of sitakisosides XI-XV,XVI and XVII,XVIII and XIX,and XX are sitakisogenin, chichipegenin, marsglobiferin and longispinogenin, respectively. They have one N-methylanthraniloyl group or tigloyl group at C-21 or C-22 or C-28. A 1 mM solution of any of sitakisosides XI-XIII,XVI and XVIII led to complete suppression of the sensation of sweetness induced by 0.2 M sucrose. Sitakisosides XIV,XV,XVII,XIX and XX,with no acyl group, had no activity. The activities of sitakisosides XI-XIII,XVI and XVIII were half those of gymnemic acids III and IV.
2 ISOLATION OF STEROIDAL SAPONINS AND STRUCTURE ELUCIDATION
During the isolation of the antisweet substsnces, ten related oxypregnane-oligoglycosides stephanosides A,B,C,D,E,F,G,H,I,and J were also isotated from the fresh stem of Stephanotis lutchuensis var.Japonica. Their structures were elucidated on the basis of a detailed study of their high-field ^1H-and ^<13>C-NMR spectra. All the sugars are beta (1*4) -linked and the aglycones are 12,20 bis-O-acyl or 12-O-acyl derivatives of sarcostin.
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