Glycosides, cardiotonic

Diverse plants (A) are sources of sugar-containing compounds (glycosides) that also contain a steroid ring (structural formulas, p. 133) and augment the contractile force of heart muscle (B) cardiotonic glycosides, cardiosteroids, or digitalis."... 

Digitalis glycosides Digitalis purpurea L., D. Cardiotonic glycosides... 

From A. membranaceous, Wang [145] obtained a saponin-enriched extract and studied its effect on the isolated heart of rats. At doses of more than 50 ftg/ml, the extract showed a positive inotropic effect, which turned negative at 30 p.g/ml. The mechanism was similar to that of cardiotonic glycosides. By bioactivity-guided fractionation, the active constituent with positive inotropic activity was isolated and characterized as astragaloside IV [146]. 

Many of the plants known to contain cardiac or cardiotonic glycosides have long been used as arrow poisons (e.g. Strophanthus) or as heart drugs (e.g. Digitalis). They are used to strengthen a weakened heart and allow it to function more efficiently, though the dosage must be controlled very... 

In the first place, they provide a number of extremely useful drugs that are difficult, if not impossible, to produce commercially by synthetic means. These include diverse groups of compounds such as the alkaloids of opium poppy, ergot, and solanaceous plants the cardiotonic glycosides of digitalis most of the antibiotics and all of the serums, vaccines, and related products. 

Okada, M., Thin-layer chromatography of cardiotonic glycosides, Kagaku No Ryoiki Zokan, 64, 103, 1964. 

Elixirs are sweetened hydroalcoholic oral solutions that are specially formulated for oral use in infants and children. Digoxin, a non-ionizable cardiotonic glycoside, is practically insoluble in water and is solubilized in propylene glycol, 10% ethanol, flavor, sweetener, preservative, and buffers to 50pg/ml in Lanoxin Elixir Pediatric from which the oral bioavailability of digoxin is 70-85%. Phenobarbital, an anticonvulsant and sedative with an intrinsic water solubility of 1 mg/ml, is solubilized in water, 23% ethanol, glucose, sodium saccharin, and flavors to 3.5 mg/ml in Donnatal Elixir. 

This last poison is a two-pronged one, for the Antiaris latex is a second source of powerful active principles, viz cardiotonic glycosides, which are even more toxic than the alkaloids of the Strychnos. 

Assay results with the two new 1,2-cis (ft-d) cardenolides show enhanced activity as compared with the two unnatural, a-D-rhamnosides. They have potencies that fall well within the range for those of the naturally occurring cardenolides. These results support the postulate that the a-D-glycosidic linkage in cardenolides containing D-sugars is unfavorable for cardiotonic activity. 

Qualitatively, the cardiotonic activity of the glycosides resides in the aglycon portion,2 which is steroidal in nature. The most widely studied aglycons are digitoxigenin [3/3,14/9-dihydroxy-5/9-card-20(22) -enolide (1) ],... 

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