Page 159 - phytochemistry I - PharmD Clinical

• Strophanthus gratus containing ouabain known as "arrow poison"
or as g-strophanthin.

Hydrolysis:

• The primary glycoside K-strophanthoside gives by hydrolysis the
secondary glycoside K- strophanthin B and one molecule of
glucose.

• K-strophanthin B by hydrolysis gives the tertiary glycoside cymarin
and one molecule of glucose.

• Cymarin hydrolyze into the genin K- strophanthidin and the
deoxysugar cymarose.

• Ouabain is hydrolysed to yield rhamnose and the aglycone
ouabagenin (G-strophanthidin).

Essential structural features for cardioactive glycosides:

1. Steroidal nucleus of the aglycone.
2. The presence of a β-unsaturated 5 or 6-membered lactone ring at

position C-17 in the β configuration.

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