The study, published in the latest edition of the Journal of Cosmetic Dermatology, investigated the effects of a formulation containing a number of well known cosmetic skin whitening ingredients and compared it to a 4 percent hydroquinone formulation.
Hydroquinone at 4 percent was significantly more effective at increasing the rate of melanin loss after sun exposure and tanning than the cosmetic formulation. However, when the antioxidant extract from Daniella ensifolia was added to the cosmetics formulation, results for the two treatments were similar, according to the study.
Potent antioxidant qualities
The extract from D. ensifolia was chosen after a screen of several hundred plant extracts showed it to have a potent antioxidant effect, the researchers explained.
According to the scientists, led by Thomas Mammone from the Estée Lauder companies, the D. ensifolia extract (the main component of which is 1-(2,4-dihydroprophenyl)-3-(2,4-dimethoxy-3-methylphenyl) propane, or DP) is slightly more potent than vitamin C, as measured by the DPPH antioxidant assay.
The researchers also measured the ability of DP to protect against oxidation in the skin surface lipids due to UVA exposure in vivo. With a topical formula containing 0.2 percent DP, there was a 60 percent reduction in lipid peroxidation of skin surface lipids, the study claims.
In vivo tests investigated the ability of the formulations to reduce the tan after 4 weeks of sun exposure. Hyperpigmentation following exposure to UV rays fades over time; but, the scientists claim that the rate at which it fades can be significantly accelerated with the use of formulations such as those tested in the study.
However, they do note that the choice of this test is one of the weaknesses of the study as it does not measure the ability to reduce long-lasting pigmentation such as freckles or age spots.
Despite this, the study claims that such a test is often used to measure the efficacy of topical products.
Source: Journal of Cosmetic Dermatology
2010, Issue 9, pages 89-95
Modification of skin discoloration by a topical treatment containing an extract of Dianella ensifolia: a potent antioxidant
Thomas Mammone, Neelam Muizzuddin, Lieve Declercq, Dominique Clio, Hugo Corstjens, Ilse Sente, Katrin Van Rillaer, Mary Matsui, Yoko Niki, Masamitsu Ichihashi, Paolo U Giacomoni and Dan Yarosh