The study, published in the latest issue of the International Journal of Cosmetic Science, investigated the effect of a wide range of fragrance raw materials on skin irritation, concluding that their inclusion into personal care products could improve product mildness.
Essential oils are widely used in the cosmetics industry for their odoriferous properties, however, according to the authors, in the past they were commonly used in traditional remedies for their functional properties.
Positive properties that have been cited in the literature include anti-bacterial, anti-fungal, anti-oxidant, anti-inflammatory, as well as the anti-irritant properties, which form the basis of the current study.
The study suggests that a wide range of fragrance materials exhibit anti-irritant properties, even at very low concentrations, that could prove useful in the modern formulation strategy which attempts to optimise product mildness.
The team from Givaudan, a global producer of fragrance and flavours, used EpiDerm samples, a human cell-derived skin model, in order to test the anti-irritant effects of the fragrance materials.
Irritation in the EpiDerm samples was induced by UVB irradiation and antiperspirant salts, chosen as the most cosmetically relevant irritants.
The presence of prostaglandin PGE2 - released from the blood vessel walls in response to infection or inflammation - was used as a marker for irritated skin.
Primarily the researchers performed a cell culture assay in order to identify a total of 39 natural and synthetic fragrance raw materials with different olfactive profiles, exhibiting a high anti-irritant activity.
The selection was given to the Givaudan perfumers who then created active fragrances that contained 40 per cent of materials with anti-irritant activity.
A selection of the active fragrances were added to a roll on antiperspirant formulation at 1 percent and then tested on the EpiDerm samples.
The formulation with the novel fragrances strongly reduced the antiperspirant-induced PGE2 formation, almost to background levels, according to the researchers.
The study notes that the levels used in the research (1 percent) reflect those actually employed in the industry, as antiperspirants contain 1 per cent fragrance, and creams between 0.3 and 0.6 per cent.
The researchers conclude that the inclusion of such specifically designed fragrances is an interesting option when attempting to formulate mild products.
Furthermore the broad range of fragrance materials exhibiting such properties and the fact that they remain active even at low concentrations, will give perfumers a wider choice, meaning that the desired olfactory properties of the finished product may not be compromised.
Source: International Journal of Cosmetic Science October 2007, Volume 29, pages 369-376 Fragrance raw materials and essential oils can reduce prostaglandin E2 formation in keratinocytes and reconstitued human epidermis Andras Natsch and Michael Wasescha