Hydrolysis of Lanatoside-C

 Lanatoside-C is a cardiac glycoside derived from Digitalis lanata and is used in treating heart conditions such as congestive heart failure and arrhythmias. It undergoes enzymatic or chemical hydrolysis to yield several active metabolites, which are responsible for its therapeutic effect.

Hydrolysis of Lanatoside-C

Lanatoside-C (C49H76O19) is composed of a sugar moiety and a steroid nucleus (aglycone), specifically digitoxigenin. Hydrolysis of lanatoside-C cleaves the sugar units, leaving behind the aglycone (digitoxigenin), which is crucial for its cardiac effects.

The reaction primarily involves breaking the glycosidic linkages between sugar moieties and the aglycone.

Step 1: Hydrolysis of the Terminal Glucose

The first step in the hydrolysis of lanatoside-C is the removal of the terminal glucose molecule. This occurs when lanatoside-C undergoes hydrolysis, producing digitoxigenin-bis-digitoxoside and a free glucose molecule:

$$\text{Lanatoside-C}(C_{49}{H}_{76}{O}_{19})+H_{2}O\to \text{Digitoxigenin-bis-digitoxoside}+\text{Glucose}$$

Step 2: Hydrolysis of Digitoxose Units

Next, the two remaining digitoxose sugars attached to the aglycone (digitoxigenin) are cleaved in successive hydrolysis reactions, yielding digitoxigenin:

$$\text{Digitoxigenin-bis-digitoxoside}+H_{2}O\to \text{Digitoxigenin-monodigitoxoside}+\text{Digitoxose}$$$$\text{Digitoxigenin-monodigitoxoside}+H_{2}O\to \text{Digitoxigenin}+\text{Digitoxose}$$

Final Product: Digitoxigenin

Once the hydrolysis is complete, the final product is digitoxigenin, the aglycone responsible for the therapeutic action. This molecule can bind to and inhibit the sodium-potassium ATPase enzyme, which increases intracellular calcium in cardiac cells, strengthening heart contractions.

Overall Reaction Summary

The complete hydrolysis of lanatoside-C can be represented as:

$$\text{Lanatoside-C}+3H_{2}O\to \text{Digitoxigenin}+\text{Glucose}+2\text{Digitoxose}$$

Clinical Relevance

The hydrolysis process of lanatoside-C is important in drug metabolism, as the active aglycone (digitoxigenin) is responsible for exerting the desired therapeutic effects on the heart. Understanding this hydrolysis pathway aids in the pharmacokinetics of cardiac glycosides, optimizing their use in clinical settings.