Oleuropein exhibits antioxidant and free radical scavenging activities which may go some way to explain the soothing qualities of the compound say scientists led by P. Perugini from the University of Pavia, Italy.
The research, published in this month's issue of the International Journal of Cosmetic Science, also investigated the protective effects of the compound against UVB irradiation however these were not found to be significant.
Oleuropein soothes the skin after UV damage
In order to test the soothing effects of the compound the team applied the extract to ten females between the ages of 20-30 years.
The extract was applied to the subjects in two forms - an oil and water emulsion and an emulsion gel - 24 hours after irradiation with UVB.
These two areas were then compared with two areas that were irradiated but left untreated.
The oleuropein formulations reduced erythema (skin reddening), transepidermal water loss and blood flow to the skin (increased blood flow can be the result of an inflammatory reaction) by 22, 25 and 30 per cent according to the scientists.
In addition, the scientists note that the form of the emulsion appeared to have little effect on the positive results of the extract.
The mechanism behind this effect is not fully understood however the scientists suggest it could be due to the inhibitory effects of the compound on reactive nitrogen species which are implicated in inflammation.
Extract shows weak protective effects
The team also investigated the protective effects of oleuropein against UVB damage, using irradiated but untreated areas and areas treated with vitamin E as controls.
Although application of oleuropein resulted in a slight decrease in skin redness compared to untreated areas, these results were not significant.
The scientists therefore conclude that: "oleuropein presents a soothing effect stronger than a protective one in the treatment of UVB induced erythema."
Oleuropein protects membranes and intracellular spaces Furthermore, the team noted that the extract is both water and lipid soluble and can reach intracellular targets as well as interacting with biological membranes.
This means that the extract could have an affect on both the cell membranes and the structures inside the cell, leading the researchers to conclude that the compound is 'very promising' as a cosmetic ingredient.