Atheronals are biologically relevant
oxysterols
An oxysterol is a derivative of cholesterol obtained by oxidation involving enzymes and / or pro-oxidants. Such compounds play important roles in various biological processes such as cholesterol homeostasis, lipid metabolism (sphingolipids, fatty a ...
formed in the reaction of cholesterol with
ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
. Atheronal A (secosterol A) is the major product of ozonolysis which is 3β-hydroxy-5-oxo-5,6-secocholestan-6-al. Atheronal B (secosterol B) is formed by the intramolecular
aldol reaction
The aldol reaction is a means of forming carbon–carbon bonds in organic chemistry.
Discovered independently by the Russian chemist Alexander Borodin in 1869 and by the French chemist Charles-Adolphe Wurtz in 1872, the reaction combines two carb ...
of atheronal A, which is 3β-hydroxy-5β-hydroxy-B-norcholestane-6β-carboxaldehyde.
Ozonolysis of cholesterol
Cholesterol
Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
, a alkene that are located in aspiratory surfactant, anticipated in the attack by ozone among the different
reactive oxygen species (ROS, for example, singlet oxygen, superoxide anion, hydroxyl radicals, and ozone). Atheronals, the major product of ozonolysis, when cholesterol is ozonized in the arrangement at high ozone fixations (>0.1%), are the substance that need be give extra care to since it have huge effect on the human body.
:
![Mechanism of the ozonolysis of cholesterol](https://upload.wikimedia.org/wikipedia/commons/4/47/Mechanism_of_the_ozonolysis_of_cholesterol.png)
In the mechanism, atheronal A are produces from a process called
ozonolysis. Next, the atheronal A go through
aldol reaction
The aldol reaction is a means of forming carbon–carbon bonds in organic chemistry.
Discovered independently by the Russian chemist Alexander Borodin in 1869 and by the French chemist Charles-Adolphe Wurtz in 1872, the reaction combines two carb ...
that occur so smoothly in the biological system to produce atheronal B. Atheronal A and B were produced in an ozone-autonomous way using the Hock-cleavage of 5α-hydroperoxy cholesterol, which can emerge from the singlet oxygen ene reaction with cholesterol. However, atheronal B is shaped effectively under acidic conditions in natural solvents, yet atheronal A is either not framed at all or is a minor part in the aqueous buffer. Practically the measures of both of the atheronals are equivalent were shaped by the response of cholesterol with human myeloperoxidase (MPO) within sight of its substrates hydrogen peroxide (H
2O
2) and Cl
−. There is five times more atheronal B that was created compare to atheronal A when cholesterol was incubated with hypochlorous corrosive (HOCl) and hydrogen peroxide. In any cases, in both the responses, immunoglobulin G (IgG) did not improve the arrangement of secosterols, recommending that singlet oxygen (
1O
2) and perhaps another oxidant, however not an ozone-like oxidant, intervened the development of secosterols.
Effects of atheronals in human body
When the ozonolysis of cholesterol reaction occurs, the atheronals as a product will quicken the normal conversion of monocytes to macrophages, are rapidly taken up by macrophages, hasten the inflammatory response on and increase the stickiness of the interior arterial walls, and contribute to the formation of arterial plaques. This cause
atherosclerosis, the hardening of the arteries. Atheronals possess biological effects that if translated to an ''
in vivo
Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...
'' setting could lead to the recruitment, entrapment, dysfunction, and ultimate destruction of macrophages, with the major leukocyte player in inflammatory artery disease. Furthermore, atheronals have additionally been detected in lung tissue, potentially from exposure of lung surfactant to the troposphere. Furthermore, such cholesterol oxidation items have been found in the brains of autopsy specimens from Alzheimer’s disease patients. The ozonolyzed cholesterol quickens amyloidogenesis in these patients. They may play a crucial job in the pathogenesis of atherosclerosis and neurodegenerative infections.
[{{cite journal , last1=Tomono , first1=Susumu , last2=Miyoshi , first2=Noriyuki , last3=Sato , first3=K , last4=Ohba , first4=Y , last5=Ohshima , first5=H , date=29 May 2009 , title=Formation of cholesterol ozonolysis products through an ozone-free mechanism mediated by the myeloperoxidase-H2O2-chloride system , journal=Biochemical and Biophysical Research Communications , volume=383 , issue=2 , pages=222–7 , doi=10.1016/j.bbrc.2009.03.155 , pmid=19345674 ]
References
Sterols
Ozone