However, since the early 1990s, squalene has become available in commercial quantities from the unsaponifiable fraction of olive oil refining. Both the shark and olive derived squalene and squalane are chemically identical, but today material of shark liver origin is significantly cheaper. This has led to blends of both qualities of shark derived being passed off as olive based material. Until today there has been no recognised method for determining origin of either squalene or squalane.
History
Ancient fishermen from Japan regularly drank an extract from the livers of deep sea sharks. They called the substance “samedawa” or “cure all”. This extract is one of the richest sources of squalene. In 1906, a Japanese chemist, Dr Mitsumaru Tsujimoto isolated a unique hydrocarbon, naming it squalene, from the Latin root Squalus (shark).
Squalene
Squalene is a highly polyunsaturated hydrocarbon from the triterpenoid family in the form of a low viscosity oil. When purified, it is pale yellow to colourless with almost no odour, although some shark derived material can retain a fish type odour. During the ensuing years after its discovery, a number of studies were carried out to understand the biochemical structure of squalene and its role in cell protection. In the 1950s, it was discovered that squalene occurs naturally in the human body. It is actually present in human sebum at levels of 8%-25% depending on age, sex and environmental factors. It plays a crucial role in the physiology of the skin and is produced during cholesterol synthesis.
Squalane
Squalane is obtained on an industrial scale by the hydrogenation of naturally occurring squalene. The chemically inert nature of squalane makes it very useful in cosmetic applications as an emollient and moisturiser. When refined correctly it is a colourless, odourless, low viscosity oil. Squalane is inert and extremely stable over a wide range of temperatures. It is absorbed rapidly into the epidermis without leaving a greasy film, with the effect of softening the skin, reducing wrinkles and aiding hydration. Squalane is an extremely useful, naturally derived oil for formulators, but until the development of the olive derived material it was always animal based. Unlike other animal harvested materials like lanolin and beeswax, the animal was killed for the oil contained within its liver. Intensive fishing for these deep water species of shark has seriously depleted their population, so this source can hardly be described as renewable. On the other hand, squalene derived from olive origin can be considered as a natural, renewable source and of vegetable origin. In addition, olive based material exhibits greater stability due to other natural components not present in the shark based material. No fish odour is present in olive derived squalene. Olive derived squalene and squalane are an obvious choice for cosmetic formulations. But as both shark and olive sources are chemically identical how can origin be determined?
Guarantee of origin of squalene and squalane by 13C/12C isotope analysis
Until recently, no valid quantitative method has been available to differentiate between shark and olive origins and so it was not possible to detect mixing. Unfortunately, this is a practice that occurs all too often. However, 13C/12C isotope analysis developed by CNRS (Centre National Recherche Scientifique – a French government specialised analytical laboratory) with the cooperation of CRM International now provides a valid quantitative method of certifying the origin. Both olive squalene and olive squalane have a delta 13C/12C of –28 whereas both shark squalene and squalane have a delta 13C/12C of –19. Results confirm that the delta 13C/12C value is specifically a function of origin and is not modified by hydrogenation. In mixed products, studies show that a linear relation exists between delta 13C/12C value and composition. The results of isotopic analysis of prepared samples correspond closely to calculated values. It has thus been possible to establish a graph relating the content of olive squalane in the prepared samples to the delta 13C/12C values determined (Fig. 3). An uncertainty of 0.30% in the determination of delta 13C/12C values allows the content of olive squalane to be established within a limit of +/–4%. Due to this method, full details of which will be published by CNRS in the near future, it is now fully possible to guarantee the origin of both squalene and squalane and to quantify any mixtures. On the basis of the complete traceability that this method provides, the market of squalene and squalane will no longer be subject to fraud. Knowledge of the animal or plant origin of squalene is important, not only for the preservation of our environment, but also in terms of its use in natural products for cosmetic and health related applications. The determination of isotopic ratios represents a very significant technique for the verification of the origin of both squalene and squalane. The clear difference in isotopic values between plant (olive) and animal (shark) origins, associated with the accuracy of the technique, allows the precise determination of the content of each origin in batches resulting from mixing. Cosmetic companies can now be assured that their product claims of “Natural, Vegetable Based, Renewable Sourced” raw material will not be compromised using squalene or squalane. The origin of each can now be certified using 13C/12C isotope analysis. It may also help save a whole population of shark species from total extinction. With more of this... ...and less of this.