Squalene

Known as an intermediate in the biosynthesis of phytosterol or cholesterol in plants or animals.

Squalene is a naturally occurring organic compound that plays a crucial role in various biological processes. It is a triterpene, a type of hydrocarbon, and is found in a variety of sources, including plants, animals, and humans.

Chemical Structure and Properties

Squalene is a polyunsaturated hydrocarbon with the chemical formula C30H50. It is characterized by its six isoprene units, which contribute to its high degree of unsaturation. This structure makes squalene a highly effective antioxidant, capable of neutralizing free radicals and protecting cells from oxidative damage.

Natural Sources

Squalene is found in several natural sources, including:

Shark Liver Oil: Historically, shark liver oil has been the most well-known source of squalene. Certain species of sharks have livers that are exceptionally rich in this compound.
Olive Oil: Squalene is also present in significant amounts in olive oil, particularly extra virgin olive oil. This makes it a valuable component of the Mediterranean diet.
Amaranth Seed Oil: Another plant-based source, amaranth seed oil, contains a high concentration of squalene.
Rice Bran Oil: This oil, derived from the outer layer of rice grains, is another notable source of squalene.
Human Sebum: In humans, squalene is a major component of sebum, the oily substance produced by sebaceous glands to lubricate and protect the skin.

Biological Functions

Squalene serves several important functions in biological systems:

Precursor to Steroids: In humans and other animals, squalene is a key intermediate in the biosynthesis of sterols, including cholesterol. This process is essential for the production of steroid hormones, vitamin D, and bile acids.
Antioxidant Properties: Due to its unsaturated structure, squalene is an effective antioxidant. It helps protect cells from oxidative stress, which can lead to aging and various diseases.
Skin Health: Squalene is a natural emollient, meaning it helps to soften and smooth the skin. It is also non-comedogenic, meaning it does not clog pores, making it suitable for all skin types.

Industrial and Medical Applications

Squalene's unique properties have led to its use in a variety of applications:

Cosmetics and Skincare

Squalene is widely used in the cosmetic industry due to its moisturizing and antioxidant properties. It is often included in:

Moisturizers: Squalene helps to hydrate the skin and maintain its natural barrier.
Anti-Aging Products: Its antioxidant properties help to reduce the appearance of fine lines and wrinkles.
Sunscreens: Squalene can enhance the efficacy of sunscreens by providing additional protection against UV-induced oxidative damage.

Pharmaceuticals

In the pharmaceutical industry, squalene is used as an adjuvant in vaccines. Adjuvants are substances that enhance the body's immune response to an antigen. Squalene-based adjuvants, such as MF59, have been used in influenza vaccines to improve their efficacy.

Nutritional Supplements

Squalene is also available as a dietary supplement. It is believed to support overall health by boosting the immune system, improving skin health, and providing antioxidant protection.

Environmental and Ethical Considerations

The extraction of squalene from shark liver oil has raised environmental and ethical concerns. Overfishing of sharks for their liver oil has led to a decline in shark populations, prompting a search for sustainable alternatives. Plant-based sources of squalene, such as olive oil and amaranth seed oil, are now being promoted as more sustainable and ethical options.

Articles/Studies

Biological importance and applications of squalene and squalane. - Squalene is a polyunsaturated hydrocarbon with a formula of C₃₀H₅₀. Squalene can be found in certain fish oils, especially shark liver oil, in high amounts and some vegetable oils in relatively smaller amounts. Human sebum also contains 13% squalene as one of its major constituents. Squalane is a saturated derivative of squalene and also found in these sources. Interest in squalene has been raised after its characterization in shark liver oil which is used as a traditional medicine for decades. Several studies exhibited results that prove certain bioactivities for squalene and squalane. Up to date, anticancer, antioxidant, drug carrier, detoxifier, skin hydrating, and emollient activities of these substances have been reported both in animal models and in vitro environments. According to promising results from recent studies, squalene and squalane are considered important substances in practical and clinical uses with a huge potential in nutraceutical and pharmaceutical industries.

Squalene and its potential clinical uses - Squalene, an isoprenoid compound structurally similar to beta-carotene, is an intermediate metabolite in the synthesis of cholesterol. In humans, about 60 percent of dietary squalene is absorbed. It is transported in serum generally in association with very low density lipoproteins and is distributed ubiquitously in human tissues, with the greatest concentration in the skin, where it is one of the major components of skin surface lipids. Squalene is not very susceptible to peroxidation and appears to function in the skin as a quencher of singlet oxygen, protecting human skin surface from lipid peroxidation due to exposure to UV and other sources of ionizing radiation. Supplementation of squalene to mice has resulted in marked increases in cellular and non-specific immune functions in a dose-dependent manner. Squalene may also act as a "sink" for highly lipophilic xenobiotics. Since it is a nonpolar substance, it has a higher affinity for un-ionized drugs. In animals, supplementation of the diet with squalene can reduce cholesterol and triglyceride levels. In humans, squalene might be a useful addition to potentiate the effects of some cholesterol-lowering drugs. The primary therapeutic use of squalene currently is as an adjunctive therapy in a variety of cancers. Although epidemiological, experimental and animal evidence suggests anti-cancer properties, to date no human trials have been conducted to verify the role this nutrient might have in cancer therapy regimens.

Chitosan - Whey protein as efficient delivery system for squalene: Characterization and functional food application.

Significance of Squalene in Rice Bran Oil and Perspectives on Squalene Oxidation.