Related Experiment Video
Updated: Aug 2, 2026
07:54
Cholesterol Efflux Assay
Published on: March 6, 2012
Parameters influencing cholesterol oxidation
Lipids
|October 1, 1993
Summary
Cholesterol oxidation is influenced by temperature and substrate form. Melting solid cholesterol or using aqueous suspensions accelerates oxidation, with pH affecting product ratios.
Area of Science:
- Biochemistry
- Food Chemistry
Background:
- Cholesterol oxidation is a critical process in food science and biological systems.
- Understanding factors influencing cholesterol oxidation is vital for food preservation and health research.
Purpose of the Study:
- To investigate the impact of temperature, oxidation time, water presence, pH, buffer type, and substrate form on cholesterol oxidation.
- To analyze the autoxidation products and their decomposition pathways.
Main Methods:
- Utilized microcrystalline cholesterol films (solid and melted) and aqueous suspensions of film fragments as substrates.
- Employed gas chromatography for quantitative analysis of cholesterol and its autoxidation products.
- Controlled variables including temperature, pH, and oxidation time.
Main Results:
- Solid cholesterol films exhibited resistance to dry autoxidation but rapidly oxidized upon melting at 125°C.
- Cholesterol oxidized faster in aqueous suspensions compared to dry states.
- pH significantly affected the ratio of 7-ketocholesterol to 7-hydroxycholesterol, and favored cholesterol beta-epoxide formation at pH 7.4.
Conclusions:
- Cholesterol's oxidation rate is highly dependent on its physical state and the presence of water.
- pH plays a crucial role in modulating the types and ratios of cholesterol oxidation products.
- Further decomposition of oxidation products occurs, indicating complex reaction pathways.
Related Concept Videos
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
02:37Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms:
01:17Oxidation of Phenols to Quinones
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
01:20Radical Autoxidation
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
01:18Lipids: Dietary Sources and Requirements
Lipids are an essential component of a balanced human diet. Triglycerides, which make up the majority of dietary lipids, are found in both saturated fats—commonly present in meat, dairy products, and certain tropical plants like coconut, and hydrogenated oils such as margarine and baking shortenings (trans fats)—and unsaturated fats, which are abundant in seeds, nuts, olive oil, and most vegetable oils. The main sources of cholesterol include egg yolks, various meats and organ meats, shellfish,...
01:29Cholesterol: Significance and Regulation
Although not a source of energy, cholesterol plays a significant role as a foundational structure for bile salts, steroid hormones, and vitamin D, as well as being a crucial component of plasma membranes. Approximately 15% of blood cholesterol is derived from our diet, with the remainder synthesized from acetyl CoA by the liver and intestines. Cholesterol is eliminated from the body through its conversion into bile salts, which are eventually discarded in the feces.
Considering cholesterol and...
Considering cholesterol and...