Hydrogen sulfide (H₂S) is a ubiquitous gaseous signaling molecule that has an important role in many physiological and pathological processes in mammalian tissues, with the same importance as two others endogenous gasotransmitters such as NO (nitric oxide) and CO (carbon monoxide). Endogenous H₂S is involved in a broad gamut of processes in mammalian tissues including inflammation, vascular tone, hypertension, gastric mucosal integrity, neuromodulation, and defense mechanisms against viral infections as well as SARS-CoV-2 infection. These results suggest that the modulation of H₂S levels has a potential therapeutic value. Consequently, synthetic H₂S-releasing agents represent not only important research tools, but also potent therapeutic agents. This review has been designed in order to summarize the currently available H₂S donors; furthermore, herein we discuss their preparation, the H₂S-releasing mechanisms, and their -biological applications.

Hydrogen sulfide (H₂S) is an endogenous gasotransmitter recently emerged as an important regulatory mediator of numerous human cell functions in health and in disease. In fact, much evidence has suggested that hydrogen sulfide plays a significant role in many physio-pathological processes, such as inflammation, oxidation, neurophysiology, ion channels regulation, cardiovascular protection, endocrine regulation, and tumor progression. Considering the plethora of physiological effects of this gasotransmitter, the protective role of H₂S donors in different disease models has been extensively studied. Based on the growing interest in H₂S-releasing compounds and their importance as tools for biological and pharmacological studies, this review is an exploration of currently available H₂S donors, classifying them by the H₂S-releasing-triggered mechanism and highlighting those potentially useful as promising drugs in the treatment of cardiovascular diseases.

The present research has been focused on the evaluation of seasonal changes in mass concentrations and compositions of heavy metals in Particular Matters (PM)₁₀ collected from a typical urban-industrial site in Acerra, a city located in an area called “triangle of death”. No significant (p < 0.05) seasonal variation was evidenced for the PM₁₀ concentration, but in all the seasons (except for autumn) exceedances of daily concentrations (50 μg m⁻³) were observed. Airborne PM was analyzed for these heavy metals: Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V and Zn, which represented about 8% of the PM₁₀ concentrations. None of the metals classified by IARC as carcinogenic in humans (group 1) exceeded on average the annual EU’s and Italy’s limit. For the mentioned heavy metals the enrichment factors (EnFs) were analyzed and highlighted high enrichment for Cd, Sb, Pb, As, Cu and Zn. Principal component analysis (PCA) for the heavy metals in PM₁₀ identified oil combustion, vehicle and industrial emissions as major sources. To assess the health risk related to the inhalation to airborne PM₁₀ metals, we applied the Cancer Risk (CR) and Target Hazard Quotient (THQ). The results showed that the CR was similar for a child and an adult, while the THQ proved to be higher for a child than for an adult. The low PM metals risk in the urban industrial site was in agreement with the ongoing lowering trend of metals in Italy and Europe.

The use of alternative energy sources, such as microwaves (MW) or ultrasounds (US), and their mutual cross-combination have been widely described in the literature in the development of new synthetic methodologies in organic and medicinal chemistry. In this review, our attention is focused on representative examples, reported in the literature in the year range 2013–2023 of selected N-containing bicyclic heterocycles, with the aim to highlight the advantages of microwave- and ultrasound-assisted organic synthesis.