Page 85 - Pharmd general phytochemistry I-Final2024_LEUCTERS

According to the type of lactone ring, cardiac glycosides are
subdivided into two groups:

 Cardenolides: characterized by: (unsaturated 5- membered

lacton ring) attached to steroid nucleus at C-17

 Bufadienolides: characterized by: (unsaturated 6-membered
lacton ring) attached to steroid nucleus at C-17

II.Sugar moiety
The sugar moiety in cardiac glycosides is characterized by:

• Being attached to C-3 of the steroidal nucleus.
• Including different types of sugars such as: hexoses, or deoxy

sugars.
• * Hexose : glucose
• * 6- deoxy hexose: rhamnose
• * 2, 6-deoxy hexose: digitoxose, cymarose

Glucose Rhamnose Digitoxose Cymarose

83