digitoxin \dig`i*tox"in\ (d[i^]j`[i^]*t[o^]k"s[i^]n), n. (Chem.)
A steroid glycoside, one of the cardiotonic chemical
substances which is extracted from the foxglove. It is a
white, crystalline substance (C41H64O13), and is a
3-substituted triglucoside of a steroid, related structurally
to digitalin and digoxin. It is used as a cardiotonic for
treatment of certain heart conditions, such as congestive
heart failure. Chemically it is
(3[beta],5[beta])-3-[(O-2,6-Dideoxy-[beta]-D-ribo-hexopyranosyl-(1[rarr]4)-O-2,6-dideoxy-[beta]-D-ribo-hexopyranosyl-(1[rarr]4)-2,
6-dideoxy-[beta]-D-ribo-hexopyranosyl)oxy]-14-hydroxy-card-20(22)-enolide.
The related compounds digitalin and digoxin are also
extracted from the foxglove (Digitalis lanata and
Digitalis purpurea). The class of steroid glycosides having
cardiotonic properties are refered to as the cardiac
glycoside group. --MI11
[PJC]
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