Abstract
Recent studies have shown that exposing antibodies or amino acids to singlet oxygen results in the formation of ozone (or an ozone-like oxidant) and hydrogen peroxide and that human neutrophils produce both singlet oxygen and ozone during bacterial killing. There is also mounting evidence that endogenous singlet oxygen production may be a common occurrence in cells through various mechanisms. Thus, the ozone-producing combination of singlet oxygen and amino acids might be a common cellular occurrence. This paper reviews the potential pathways of formation of singlet oxygen and ozone in vivo and also proposes some new pathways for singlet oxygen formation. Physiological consequences of the endogenous formation of these oxidants in human tissues are discussed, as well as examples of how dietary factors may promote or inhibit their generation and activity.
Highlights
Singlet oxygen (1O2) is an electronically excited form of oxygen which is well known to be formed when photosensitizers such as chlorophyll or the aromatic dye rose bengal absorb light energy and transfer some of that energy to molecular oxygen [1, 2]
It was shown that antibodies or amino acids catalyze the conversion of singlet oxygen (1O2) to ozone (O3) and that this reaction occurs during the killing of bacteria by activated neutrophils [7, 8]
It is generally considered that production of singlet oxygen by neutrophils is dependent on myeloperoxidase (MPO) which catalyzes the formation of hypochlorous acid (HOCl) from hydrogen peroxide (H2O2) and chloride ion (see equation (1)), followed by reaction of HOCl with hydrogen peroxide anion (HO2−) the significance of the (see equation (2)) [7, 37]. reaction between HO2−
Summary
Singlet oxygen (1O2) is an electronically excited form of oxygen which is well known to be formed when photosensitizers such as chlorophyll or the aromatic dye rose bengal absorb light energy and transfer some of that energy to molecular oxygen [1, 2]. Ozone (O3) is best known as occurring in the stratosphere where it shields organisms on earth from ultraviolet C and much of ultraviolet B radiations, which are the most damaging UV components of solar radiations because they are readily absorbed by DNA [4, 5]. It was shown that antibodies or amino acids catalyze the conversion of singlet oxygen (1O2) to ozone (O3) and that this reaction occurs during the killing of bacteria by activated neutrophils [7, 8]. Since both singlet oxygen and ozone are highly reactive oxygen species, a full understanding of their mechanisms of formation and action in vivo is necessary. This paper reviews the various reported mechanisms of the endogenous formation of these reactive oxygen species (ROS), the potential relevance of such pathways in human physiology, and how dietary factors affect the generation and activity of these oxidants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
