Acylated C-21 steroidal bisdesmosidic glycosides from Caraluma umbellata.
From the whole plant of Caraluma umbellata, three new C-21 steroidal glycosides, named as carumbellosides III-V, were isolated and their structures elucidated by extensive spectroscopic experiments, devoid of any derivatisation, as caralumagenin 3-O-beta-D-glucopyranosyl(1-->4)-beta-D-digitalopyranoside-20-O-be ta- D-glucopyranoside, caralumagenin 3-O-beta-D-glucopyranosy(1-->4)- beta-D-digitalopyranoside-20-O-(2-O- benzoyl)-beta-D-glucopyranoside and caralumagenin 3-O-[6-O-benzoyl-beta-D-glucopyranosyl(1-->4)]-beta-D- digitalopyranoside-20-O-(2-O-benzoyl)-beta-D-glucopyranoside. The determination of the absolute configuration of the aglycone as (20 R), the conformations of the sugars and the unambiguous assignments of their NMR spectroscopic signals were achieved by a combination of 2D-NMR techniques. The isolates were devoid of significant cytotoxity in the UIC human cancer cell panel.
Qiu
S X
SX
Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago 60612, USA.
Lin
L Z
LZ
Cordell
G A
GA
Ramesh
M
M
Kumar
B R
BR
Radhakrishna
M
M
Mohan
G K
GK
Reddy
B M
BM
Rao
Y N
YN
Srinivas
B
B
Thomas
N S
NS
Rao
A V
AV
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006027:Glycosides / Q000032:analysis* / Q000302:isolation & purification; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D010944:Plants / Q000737:chemistry*; D013256:Steroids / Q000032:analysis* / Q000302:isolation & purification; D014407:Tumor Cells, Cultured / Q000187:drug effects
D006027:Glycosides; D013256:Steroids