From the fresh stem of Stephanotis lutchuensis var.japonica, we have isolated five new oleane glycosides named sitakisosides I-V (1-5). Their structures were determined on the basis of spectroscopic data and chemical evidence. Sitakisoside V showed the strongest antisweet activity among sitakisosides I-V.
From the fresh stem of Stephanotis lutchuensis var. japonica, ten new oleanane-type triterpenoid glycosides, named sitakisosides XI-XX (1-10), were isolated. Their structures were determined on the basis of spectroscopic data and chemical evidence. The results show that all have a 3-O-β-D-xylopyranosyl(1→6)-β-D-glucopyranosyl(1→6)-β-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. Sitakisosides XI-XIII, XVI and XVIII, having an acyl group, showed antisweet activity.
Antisweet Natural Products. XIV. Structures of Alternosides XI-XIX from Gymnema alternifolium.
作者:Kazuko YOSHIKAWA、Kumiko TAKAHASHI、Koji MATSUCHIKA、Shigenobu ARIHARA、Hsen-Chang CHANG、Jen-Der WANG
DOI:10.1248/cpb.47.1598
日期:——
From the fresh roots of Gymnema alternifolium, nine new oleanane-type triterpenoid glycosides, named alternosides XI-XIX (1-9), were isolated, together with two artificial compounds 10 and 11, and two known compounds, sitakisosides X (12) and XVII (13). Their structures were determined on the basis of spectroscopic data and chemical evidence. Compounds 1-3 are 3-O-glycosides of chichipegenin having a tigloyl group at C-22, 28 and 16, respectively. Compounds 4-7 are 3, 28-bis-O-glycosides of chichipegenin having a tigloyl group at C-22. Compounds 8 and 9 are 3, 28-bis-O-glycosides of longispinogenin. Compounds 1-7 having an acyl group showed antisweet activity.
Five new oleanane-type saponins 1–5 together with a known saponin 6 and a steroidal glycoside 7 were isolated from Polaskia chichipe Backbg., and their structures were determined from their 1D and 2D NMR and HRFABMS spectral data. The six isolated saponins 1–6 were tested for their effects on the melanogenesis of B16 melanoma 4A5 cells. Compound 1 exerted an inhibitory effect at 100 μM whereas compound 3 promoted melanogenesis at the same concentration, even though these two compounds contain the same aglycon structure. The dose-dependent activities of compounds 1 and 3 on melanin synthesis were investigated.
known analogue (4), were isolated from the whole plant of Cissampelospareira var. hirsuta. Their chemical structures were elucidated by extensive spectroscopic data (IR, HR-ESI-MS, 1H-NMR, 13C-NMR, DEPT, 1H-1H COSY, HSQC, HMBC, NOESY) and the microhydrolysis method. The isolation of compounds 1–4 represents the first report of polyhydroxylated oleanane triterpenoids from the family Menispermaceae. All