1 / 17

The Cardiac Glycosides Cardio-active Glycosides

The Cardiac Glycosides Cardio-active Glycosides. A Group of steroidal glycosides act as cardiotonic agent. They increase tone, excitability and contractility of cardiac muscles. Structural features :. - Steroidal nucleus must be present. -3 b -OH group involved in glycosidic linkage.

preston-puckett
Download Presentation

The Cardiac Glycosides Cardio-active Glycosides

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Cardiac GlycosidesCardio-active Glycosides A Group of steroidal glycosides act as cardiotonic agent. They increase tone, excitability and contractility of cardiac muscles.

  2. Structural features: -Steroidal nucleus must be present. -3b-OH group involved in glycosidic linkage. -14b-OH group at C-14. - A/B ring junction cis – - B/C ring junction trans- -C/D ring junction cis -Additional OH groups at C-5, C-11 and C-16 may be present. -The presence of lactone ring: 14

  3. According to the type of lactone ring Cardiac Glycosides are classified into: • Cardinolides: They are C-23 containing 5-membered unsaturated lactone ring e.g. Digitalis & Strophanthus • Bufadienolides: They are C-24 containing 6-membered unsaturated lactone ring e.g. Squill

  4. The Sugar Part: • The glycosides usually contain 3 to 4 sugars attached at C-3 OH. • Beside Glucose and Rhamnose they usually contain deoxysugars.

  5. The Cardinolides1- Digitalis Glycosides • Digitalis is Known as “foxglove” • The most important species includes: • 1) Digitalis purpurea • 2) Digitalis lanata

  6. Digitalis contain three major aglycones:

  7. 2- StrophanthusGlycosides Obtained from Strophanthus kombé The used part is the seeds. The common aglycone is K-strophanthidin

  8. 14 10

  9. Bufadienolides1- Squill Glycosides • They have 6-membered lactone ring. • Obtained from Squill bulbs. • Aglycone contains only two hydroxyl groups at C-3 and C-14.

  10. Physical and Chemical properties of cardiac glycosides: • Solubility: • Glycosides are soluble in water and alcohols. • Increase number of sugars increase water solubility. • Aglycones soluble in CHCl3 and EtOAc.

  11. Stability: 1) Acid hydrolysis: Split sugars from the aglycone first. 2) Enzymatic hydrolysis: Split sugars stepwise starting from the terminal sugar. 3) Elevated temperature: Cause dehydration by removal of C-14 OH group to give inactive anhydro-form

  12. Medicinal Importance: • -They are Cardiotonics used to treat Congestive heart failure. • -They increase force of contraction of cardiac muscles without increasing oxygen consumption. • -Increase cardiac output. • The diastolic phase lasts longer, thus decreases heart rate. • -Have diuretic effect due to increase amount of blood passing through the kidney.

  13. Chemical Identification: General test for steroids: Liebermann’s test: Glycoside in acetic anhydride + Few drops of conc. H2SO4 Reddish violet Green Test for Deoxysugars: Keller-Kiliani’s Test: Glycoside in gl. acetic containing traces of FeCl3 + conc. H2SO4 on the wall of the tube Acetic acid layer acquire Bluish-greencolour (Digitalis) Acetic acid layer acquire Red colour (Squill)

  14. Test for 5-membered lactone ring: • Legal’s test: • Cardenolide in pyridine + Na nitroprusside + NaOH deep redcolour. • Kedde’s test: • Cardenolide + 3,5 dinitrobenzoic acid (Kedde’s reagent A) + NaOH (Kedde’s reagent B) violet colour.

More Related