A review of hydrogen sulfide (HS) donors: Chemistry and potential therapeutic applications.

Hydrogen sulfide (HS) is a ubiquitous small gaseous signaling molecule, playing an important role in many physiological processes and joining nitric oxide and carbon monoxide in the group of signaling agents termed gasotransmitters. Endogenous concentrations of HS are generally low, making it difficult to discern precise biological functions. As such, probing the physiological roles of HS is aided by exogenous delivery of the gas in cell and animal studies. This need for an exogenous source of HS provides a unique challenge for chemists to develop chemical tools that facilitate the study of HS under biological conditions. Compounds that degrade in response to a specific trigger to release HS, termed HS donors, include a wide variety of functional groups and delivery systems, some of which mimic the tightly controlled endogenous production in response to specific, biologically relevant conditions. This review examines a variety of HS donor systems classified by their HS-releasing trigger as well as their HS release profiles, byproducts, and potential therapeutic applications.