JOURNAL OF COSMETIC SCIENCE 62 has shown that modifying the expression of certain genes improved crop plants and increased its resistance to low temperature and salinity of the soil (5,13). The amaranth genetic improvement should tend to increase the content of squalene and reduce raw fat (5). The “Szarlat” (Lomża, Poland)—commercializing Amaranth-derived squalene company— has developed a technology called cold-pressing method. Cold-pressing method is a unique technology to produce oil from the seeds of amaranth without using organic solvents. By using this method, the contents and properties of squalene in amaranth oil remain unchanged. This method is extremely diffi cult in the extraction of small sized and low-fat content seeds. Developed methods allow the extraction of the native oil called virgin oil (virgine) (13–15). PERSPECTIVE OF ADVANTAGES Plant-based squalene may be used in cosmetics and personal care products according to the general provisions of the Cosmetics Directive of the European Union. The Cosmetic Ingredient Review Expert Panel noted that studies indicated that squalene was slowly absorbed through the skin. The toxicity of squalene by all routes was low. At 100% con- centrations, the compound is a nonirritant to the skin and eyes. Products containing squalene were not dermal irritants or sensitizers (16). Olive oil is graded as a healthy agent, not on the quality of the oil, but on the accom- panying substances dissolved in it. Amaranth grains contain only 7–7.7% lipids, and these lipids are extremely valuable because of the presence of ingredients like squalene, unsaturated fatty acids, vitamin E as tocopherols, tocotrienols, and phytosterols, which are not seen together in other common oils (e.g., olive oil) (5,14,15). Amaranth squa- lene with accompanying compounds shows a high biological activity as is proven from the results of numerous researches (6). The advantages of amaranth oil in the near future can become one of the basic squalene sources (17) despite a bit higher price than other common oils. Human skin, covering the entire outer surface of the body, is the largest organ and is constantly exposed to sunlight stress, including ultraviolet (UV) light irradiation. The skin tissue is rich in lipids, which are thought to be vulnerable to oxidative stress from sunlight. Squalene is a structurally unique triterpene compound, which is one of the main components (about 13%) of skin surface lipids (6,16). High content of squalene in our skin is good enough proof of its importance in this organ. Squalene helps the skin retain moisture, making it smooth and elastic. But its major role is to protect skin from UV radiation and thereby taking into account its anticancer and immuostimulating properties to protect from skin cancer. Undoubtedly, more extensive use of squalene in medicine and cosmetics is still ahead (17,18). ROLES OF SQUALENE Antioxidant. Squalene has been reported to possess antioxidant properties. In vitro experi- mental evidence indicates that squalene is a highly effective oxygen-scavenging agent. Subsequent to oxidative stress such as sunlight exposure, squalene functions as an effi cient

PLANT-BASED SQUALENE IN COSMETOLOGY 63 quencher of singlet oxygen and prevents the corresponding lipid peroxidation at the hu- man skin surface (19,20). Other studies have shown the effect of squalene on reducing superoxide anion. These results suggest the possible role in alleviating skin irritation (6,21). Topical application of antioxidants has been recently suggested as preventive ther- apy for skin photoaging and UV-induced cancer (20). It has been known that treating the skin with oils offers considerable protection from sunburn because of a strong absorption band in the erythemogenic region (21). Topical application of the cream containing anti- oxidants (vitamin E, CoQ10, squalene) led to a signifi cant increase in the sebum level (22). This could be a signifi cant proof of the unique composition of amaranth oil. Emollient. Amaranth oil has been reported to contain relatively large amount of squalene, which is used as an important ingredient in skin cosmetics and penetrants (13). Squalene as a natural emollient is quickly and effi ciently absorbed deep into the skin, restoring healthy suppleness and fl exibility without leaving an oily residue (6,23). When applied to washed or sun exposed skin and hair, squalene helps to restore the lost oils. It readily forms emulsions with fi xed oils and lipophilic substances and does not oxidize nor turn rancid. Squalene has also been found to accelerate dye-dispersion in lipsticks, producing a high gloss and acts as a long-lasting fi xative for perfumes. (21). Skin hydration. Since squalene is a part of our skin’s natural lubrication, it has a moistur- izing effect on the skin. The ingredient not only provides hydration but also helps reduce the appearance of wrinkles and fi ne lines by fi lling the skin with water. On the basis of amaranth oil, characterized by a unique content of squalene, forms such as emulsion of “oleogel” can be used (17). The vernix caseosa (VC) substitute based on squalene, which is composed of different lipid fractions mixed with squalene, triglycerides, cholesterol, ceramides, and fatty acids, mimic the lipid composition of VC. This substitute can be used as an innovative barrier cream for barrier-defi cient skin (i.e., psoriasis) (6,24). There are no confi rmed clinical studies for atopic dermatitis by using VC substitute. Treating skin diseases. Seborrheic dermatitis and acne (following seborrheic dermatitis) are the most common skin disorders. It is important to keep the same level ingredients of sebum. The correct amount of free, unsaturated fatty acids (linoleic acid) ensures the proper density, fl uidity, and viscosity of sebum. If the sebum is suffi ciently liquid and not very viscous, it freely fl ows on the skin surface causing hyperkeratosis. Decisive is the percentage of triglycerides and squalene: the more the squalene, the less the acne changes. Squalene is often used in acne-against cosmetics that changes the composition of the lipid layer of the skin—when the content of squalene increases, fats are reduced appropriately (25). The protective action of squalene and alkylglycerols from bacterial and fungal infection indicates that they could be recommended for patients suffering from atopic dermatitis. Patients with xerosis and disturbances of skin barrier are easily susceptible to atopic der- matitis (25). These studies were based on shark liver oil. Analysis on the effects of cosmetics containing squalene have made several proposals. First, by improving the composition of sebum (i.e., by the enrichment of essential fatty acids and squalene), keratosis disorders are eliminated. Second, these cosmetics could prevent the skin irritations caused by product oxidation. Third, these act as bacteriostatic and antifungal agents to limit the number of microorganisms settled in the follicles (26).