Strategies for the Design of Donors and Precursors of Reactive Sulfur Species.

Reactive sulfur species (RSS) play regulatory roles in biological systems. Many RSS are highly reactive and transient molecules, making their study difficult. RSS donors or precursors, which are used to specifically produce or deliver RSS, are useful research tools, as well as possible therapeutic agents. In this Minireview, we summarized the chemical strategies that have been used in the design of donors/precursors of hydrogen sulfide relevant RSS (including hydrogen sulfide, hydrogen polysulfides, persulfides, and S-nitroso-hydrogen sulfide). The potential problems of applying these strategies in biological settings are also discussed.

A smartphone based device for the detection of sulfane sulfurs in biological systems.

Sulfane sulfur species are newly recognized signaling molecules that play physiological roles in many biological events. The development of new technologies for the detection of sulfane sulfurs is important. Point-of-care (POC) devices are in-field rapid and low-cost detectors that are more convenient to use than bulky and expensive standard instruments. In this report, a new fluorescent probe (SSP5) was designed to detect sulfane sulfurs using a POC sulfane sulfur smartphone spectrum apparatus (S4A). This probe proved to be sensitive and selective for sulfane sulfur species over other biologically relevant sulfur species such as cysteine and H2S. The low-cost and compact S4A has achieved comparable performance to standard laboratory equipment in both a standard buffer system and a synthetic urine system. The proposed system (SSP5 + S4A) has the potential for high accuracy and rapid detection of sulfane sulfur species in remote and low resource settings.

Rational Design of a Dual-Reactivity-Based Fluorescent Probe for Visualizing Intracellular HSNO.

Thionitrous acid (HSNO), the smallest S-nitrosothiol, is emerging as a potential key intermediate in cellular redox regulation linking two signaling molecules H2 S and NO. However, the chemical biology of HSNO remains poorly understood. A major hurdle is the lack of methods for selective detection of HSNO in biological systems. Herein, we report the rational design, synthesis, and evaluation of the first fluorescent probe TAP-1 for HSNO detection. TAP-1 showed high selectivity and sensitivity to HSNO in aqueous media and cells, providing a useful tool for understanding the functions of HSNO in biology.

Phosphonothioate-Based Hydrogen Sulfide Releasing Reagents: Chemistry and Biological Applications.

Hydrogen sulfide (H2S) is a newly recognized gasotransmitter. Studies have demonstrated that the production of endogenous H2S and the exogenous administration of H2S can regulate many physiological and/or pathological processes. Therefore, H2S releasing agents (also known as H2S donors) are important research tools in advancing our understanding of the biology and clinical potential of H2S. Among currently available donors, GYY4137 is probably the most well-known and has been used in many studies in the past 10 years. Recently, a number of GYY4137 derivatives (e.g., phosphonothioate-based compounds) have been developed as H2S donors. In this review, we summarize the development and application of these donors, which include Lawesson's reagent, substituted phosphorodithioates, cyclic phosphorane analogs, and pH-controlled phosphonamidothioates (JK donors). These donors have advantages such as good water-solubility, slow and controllable H2S release capability, and a variety of reported biological activities. However, it should be noted that the detailed H2S release profiles and byproducts under real biological systems are still unclear for many of these donors. Only after we figure out these unknowns we will see better applications of these donors in H2S research and therapy.

Benzothiazole Sulfinate: A Sulfinic Acid Transfer Reagent under Oxidation-Free Conditions.

Sulfinic acids are commonly encountered intermediates found in natural product synthesis and medicinal chemistry. However, because of high reactivity, instability, and harsh reaction conditions, they are difficult to synthesize. Herein we have developed an oxidation-free method to produce sulfinic acids and sulfinate salts using 2-sulfinyl benzothiazole (BTS). We have also demonstrated the synthetic usefulness by developing one-pot syntheses of sulfones and sulfonamides.