Hydrogen sulfide (H2S) is one of the important gasotransmitters, a family of small gaseous signaling molecules. According to recent publications, hydrogen sulfide possesses anti-inflammatory,1 anti-tumor,2 cardiovascular protective,3 and antioxidant4 activities. However, the biological response to H2S strongly depends on H2S concentration and the specific site in the system.5 The use of H2S gas or inorganic sulfides is problematic due to the toxicity and non-specific systemic action. Therefore, finding efficient approaches to the delivery of hydrogen sulfide to the target location at the right concentration with appropriate rate is vital for the understanding of the biology, as well as realizing the clinical potential of hydrogen sulfide. 6 Among other strategies, using photocaged H2S donors is a promising approach, as it provides spatiotemporal control of H2S release.7 In our group, H2S-releasing agents that are based on o-naphthoquinone methide precursors (NQMPs) were designed and synthesized, and their ability to release H2S under UV irradiation was studied. Comparing to other photolabile H2S donors, these NQMPs-based H2S donors demonstrated much higher yield of H2S. Thus, irradiation of these donors in the presence of thiols allows for achieving over 90% of photo-release efficiency. The intermediates and byproducts formed during these photoreactions were characterized, allowing us to gain an insight into the mechanistic pathways.
1. Li, L.; Moore, P.K. hydrogen sulfide in health and disease: a breath of not so fresh air? Trends Pharmacol. Sci. 2008, 29, 84-90.
2. Shrotriya, S.; Kundu, J.K.; Na, H.K.; Surh, Y.J. Diallyl Trisulfide Inhibits Phorbol Ester–Induced Tumor Promotion, Activation of AP-1, and Expression of COX-2 in Mouse Skin by Blocking JNK and Akt Signaling. Cancer Res. 2010. 70,1932-1940.
3. Sodha, N.R.; Clements, R.T.; Feng, J.; Liu, Y.; Bianchi, C.; Horvath, E.M.; Szabo, C.; Sellke, F.W. The effects of therapeutic sulfide on myocardial apoptosis in response to ischemia–reperfusion injury. Surger Eur J Cardiothorac Surg. 2008. 33, 906-913.
4. Osborne, N.N.; Ji, D.; Majid, A.S.A.; Del Soldata, P.; Sparatore, A. Glutamate oxidative injury to RGC-5 cells in culture is necrostatin sensitive and blunted by a hydrogen sulfide (H2S)-releasing derivative of aspirin (ACS14). Neurochem. Int., 2012. 60, 365-378.
5. Zheng, Y.; Ji, X.; Ji, K.; Wang, B. Hydrogen sulfide prodrugs—a review. Acta Pharm. Sin. B., 2015. 5, 367-377.
6. Zhao, Y.; Biggs, T.D.; and Xian, M. Hydrogen sulfide (H2S) releasing agents: chemistry and biological applications. Chem. Commun. 2014. 50, 11788-11805.
7. Powell, C.R.; Dillon, K.M.; Matson, J.B. A review of hydrogen sulfide (H2S) donors: Chemistry and potential therapeutic applications. Biochem. Pharmacol. 2018. 149, 110-123.