Hydrogen sulfide (H2S), a well-known poisonous gas, has been recognized as a critical endogenous gas transmitter in the past decade.

Sulfur dioxide, an air pollutant, is easily hydrated to sulfites and bisulfites and extremely harmful to human health.

No abstract

Hydrogen sulfide (H 2 S), the third gas signal molecule in mammals is studied more and more deeply, and great progress has been made on organic small molecule hydrogen sulfide donors. However, no hydrogen sulfide donor has been marketed as a drug yet. Metformin is a first-line drug for the treatment of diabetes. And some other biological activities such as anti-obesity, anticancer, and anti-aging have been disclosed in recent years. H 2 S donor has also shown promising prospect in antitumor, cardiovascular protection, anti-inflammation, ion channel regulation and anti-oxidation activities. In view of the potential of hydrogen sulfide and metformin for treatment of diseases, a novel hydrogen sulfide donor, metformin hydrosulfide, was thus designed. Till now, there is no report of this type of hydrogen sulfide donor. In our work, metformin hydrochloride was first basified to obtain metformin, followed by reaction with hydrogen sulfide to afford metformin hydrosulfide. The structure was fully characterized by 1 H NMR, 13 C NMR, elemental analysis and X-ray crystal. The content of hydrogen sulfide was determined by iodometry method, lead acetate test and methylene blue spectrophotometric method to be more than 96.00%. The metformin level was determined by high-pressure liquid chromatography (HPLC) to be more than 98.50%. The stability of metformin hydrosulfide was evaluated by iodometry method in solution and solid, respectively. The results indicate that metformin hydrosulfide is a promising new type of hydrogen sulfide donor which deserves further research and development.