Final answer:
Xanthine derivatives stimulate the CNS and relax bronchial smooth muscle, which is especially useful in treating conditions like asthma.
Step-by-step explanation:
Xanthine derivatives, such as caffeine, theophylline, and theobromine, elicit their effects through a variety of mechanisms, including the stimulation of the central nervous system (CNS), diuresis, cardiac muscle stimulation, and the relaxation of smooth muscle. Among these, a particularly important effect for therapeutic applications is the ability to relax bronchial smooth muscle. This is of interest in conditions like asthma where reducing airway hyper-responsiveness can be beneficial. While they do not directly stimulate beta-adrenergic receptors or stabilize mast cell membranes as some other drugs might, they have their own distinctive mode of action that can be therapeutically useful.