Collect. Czech. Chem. Commun.
1998, 63, 1663-1670
https://doi.org/10.1135/cccc19981663
Conformational Preference of Two Toad Poison Bufadienolides, Cinobufagin and Bufotalin
Yoshiaki Kamanoa, Ayano Kotakea, Toshihiko Nogawaa, Hirohumi Hashimaa, Machiko Tozawaa, Hiroshi Moritab, Koichi Takeyab, Hideji Itokawab, Ichiro Matsuoc, Yoshitatsu Ichiharac, Pavel Drašard and George R. Pettite
a Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
b Department of Pharmacognosy, School of Pharmacy, Tokyo University of Pharmacy & Life Science, 1432-1 Horimouchi, Hachioji, Tokyo 192-0392, Japan
c Meiji Institute of Health Science, Meiji Milk Products Co. Ltd., 540 Naruda, Odawara, Kanagawa 250-0862, Japan
d Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
e Cancer Research Institute and Department of Chemistry, Arizona State University, Tempe, Arizona 85287-1604, U.S.A.
Abstract
The solution state conformations of pyran-2-one ring (E ring) of two toad poison bufadienolides, cinobufagin and bufotalin, were analyzed by using NOE experiments at low temperatures and molecular dynamics simulation study. The rotation of E ring of the two bufadienolides, was found to be affected by the 14β,15β-epoxy and 16β-acetoxy groups and to be restricted at low temperatures. In the experimental, cinobufagin and bufotalin were isolated from Ch'an Su by the new chromatographic methods using the hydrophobic gel sephadex LH-20 and HP-cellulofine as carriers.
Keywords: Steroids; Bufadienolides; Cinobufagin; Bufotalin; Conformation analysis; NMR spectroscopy; Semiempirical calculations; Ab initio calculations; Molecular mechanics.
