Products of Sulfide/Selenite Interaction Possess Antioxidant Properties, Scavenge Superoxide-Derived Radicals, React with DNA, and Modulate Blood Pressure and Tension of Isolated Thoracic Aorta.

Selenium (Se), an essential trace element, and hydrogen sulfide (HS), an endogenously produced signalling molecule, affect many physiological and pathological processes. However, the biological effects of their mutual interaction have not yet been investigated. Herein, we have studied the biological and antioxidant effects of the products of the HS (NaS)/selenite (NaSeO) interaction. As detected by the UV-VIS and EPR spectroscopy, the product(s) of the HS-NaSeO and HS-SeCl interaction scavenged superoxide-derived radicals and reduced cPTIO radical depending on the molar ratio and the preincubation time of the applied interaction mixture. The results confirmed that the transient species are formed rapidly during the interaction and exhibit a noteworthy biological activity. In contrast to HS or selenite acting on their own, the HS/selenite mixture cleaved DNA in a bell-shaped manner. Interestingly, selenite protected DNA from the cleavage induced by the products of HS/HO interaction. The relaxation effect of HS on isolated thoracic aorta was eliminated when the HS/selenite mixture was applied. The mixture inhibited the HS biphasic effect on rat systolic and pulse blood pressure. The results point to the antioxidant properties of products of the HS/selenite interaction and their effect to react with DNA and influence cardiovascular homeostasis. The effects of the products may contribute to explain some of the biological effects of HS and/or selenite, and they may imply that a suitable HS/selenite supplement might have a beneficial effect in pathological conditions arisen, e.g., from oxidative stress.