What type of glycosides are considered inert until mixed with water or enzymes?

Cyanogenic glycosides are compounds that release toxic cyanide when they come into contact with water or specific enzymes. They are considered inert while in their glycoside form, which means they do not pose a threat until they are hydrolyzed, either via enzymatic action or through exposure to moisture. This characteristic is significant because it allows the plant to store potentially harmful compounds without immediate toxicity.

In contrast, the other types of glycosides mentioned do not share this property. Cardiac glycosides, for example, are active compounds that affect heart function and do not require activation through water or enzymes to exert their pharmacological effects. Saponins can exhibit toxic effects and have surfactant properties, impacting cellular membranes without needing enzymatic conversion. Glucosinolates can be broken down into various biologically active components, such as isothiocyanates, but the process does not render them inert in the same way that cyanogenic glycosides are prior to hydrolysis.

Therefore, the unique inertness of cyanogenic glycosides until they interact with water or enzymes makes them the correct choice in this context.