According to Schaefer et al. (2000), sunscreens are products that protect the skin against DNA, cell and tissue damage, cancer, mutations, immunosuppression, dermatitis, photoaging and photodermatoses. For this reason, sunscreen chemicals should have the following characteristics: they should be chemically, photochemically and thermally inert; should not be toxic, sensitizing, irritant nor mutagenic; should have appropriate solubility and no volatility in the final product. Besides this, the product should not be absorbed by the skin, should not change its color or discolor the skin, nor stain clothes; it should be colorless and compatible with the other ingredients of the cosmetic formulation and its packaging; in addition to being chemically stable in the final product (Rosen, 2003).
The skin is formed by several layers of fat-cells. Therefore, the more lipophilic the sunscreen, the greater its substantivity. In other words, the product has the ability to retain its effectiveness for prolonged periods of time, especially when exposed to water (Mansur, 1984).
The coffee oil studied in this work has many of the properties required for sunscreens and may be considered a good ingredient for industrial applications. Moreover, in addition to being a 100% natural product, it contains a series of lipophilic substances with important antioxidant characteristics, such as tocopherols, and is able to protect the skin against UVB radiation.
When high wax and oil contents are combined with a composition rich in unsaturated acids, a high SPF value and high unsaponifiable matter content, the result is a product or ingredient that is ideally suited for formulating high quality cosmetic products able to promote moisture retention and provide sun protection.
Those attributes are found in the lipid fraction of the majority studied species. Two species C. arabica and C. canephora are responsible for almost 100% of coffee production and their oils are available to use in industry. Wild species like C. salvatrix and C. stenophylla are not cultivated and their oils are only used in experimental conditions.
C. arabica, besides its cosmetic properties, is the most cultivated specie around the world and it presented a high intraspecific variability. These facts suggest that this specie should be further studied in depth with regard to its genetic variability.