Lc. Chang et al., THE RHAMNOSE MOIETY OF SOLAMARGINE PLAYS A CRUCIAL ROLE IN TRIGGERINGCELL-DEATH BY APOPTOSIS, Biochemical and biophysical research communications, 242(1), 1998, pp. 21-25
Solamargine, solasodine and khasianine steroidal alkaloids are utilize
d to determine the role of carbohydrate moiety in the mechanism of apo
ptosis. The CS side chain of solamargine, khasianine and solasodine co
ntains 4'Rha-Glc-Rha2', 4'Rha-Glc and H, respectively. Solamargine pos
sessed potent cytotoxicity to human hepatoma cells, while the cytotoxi
city of khasianine was greatly diminished. Nevertheless, only solamarg
ine could induce ''sub-G1'' of apoptotic feature in flowcytometry. Thu
s, the 2'Rha moiety of solamargine may play a crucial role in triggeri
ng cell death by apoptosis. In addition, the molecular modeling of sol
amargine indicated that the 2'Rha moiety was adjacent to the rigid ste
roid structure, and drastically changed the dihedral angle of the glyc
osidic bond. The regulations of TNFR I and II expression by different
carbohydrate moieties were also distinct. It implied that the carbohyd
rate moieties of steroidal alkaloids might alter the binding specifici
ty to steroid receptors and consequently regulate the gene expression
in different manners. (C) 1998 Academic Press.