Researchers develop sunscreen that protects against wrinkles and flaccidity

The formula, developed at USP, combines photoprotective substances, Ginkgo biloba and red marine algae extracts with vitamins A, C and E

By Karina Toledo

Agência FAPESP – A team of Universidade de São Paulo researchers in the city of Ribeirão Preto have developed a sunscreen that goes beyond protecting against the harmful effects of ultraviolet radiation and additionally improves the texture and elasticity of skin, stimulates cellular renovation, hydrates the skin and reduces wrinkles.

The formula combines two types of photoprotective substances and the extracts of Ginkgo biloba and red marine algae. The researchers also added vitamins A, C and E.

“In older studies, we had confirmed that some vegetable extracts were capable of improving the conditions of sun-aged skin and making it less vulnerable to radiation damage. Then we had the idea of incorporating these extracts into sunscreens to strengthen the effect of filters in order to bolster the protective effect,” explains Patrícia Maia Campos, coordinator of the study.

The vitamins were added to stimulate cellular renovation and improve the general condition of the skin, yielding a multifunctional cream, explained the pharmaceuticals researcher.

The project entitled “Development, stability and efficacy of preclinical photo protector formulations containing fat-soluble vitamins and Ginkgo biloba extracts and red seaweeds,” was funded by FAPESP under its Regular Research Awards program.

The first step was to develop a formula containing photostable filters that are capable of remaining active in the presence of light and have a sun protection factor (SPF) of 20. To develop such a formula, we combined chemical (organic) filters that consisted of molecules capable of absorbing ultraviolet rays and transforming them into harmless low-energy rays with physical (inorganic) filters that reflect radiation and impede its penetration of the skin. 
 
“We added vegetable extracts and vitamins. We tested several combinations of ingredients. The challenge was to create a product with adequate sensory characteristics, because if you a make very greasy cream or one that doesn’t spread, no one uses it,” the researcher said.

The product’s dermal compatibility was evaluated and its safety for cosmetic use verified in partnership with the French pharmaceutical laboratory Evic. While the study was ongoing, one of the group’s articles was presented at the 2008 Congress of the International Federation of Societies of Cosmetic Chemists in Barcelona.

The results caught the attention of researchers at Chanel’s Centre de Recherches et d'Investigations Épidermiques et Sensorielles.

“They invited us to visit the center and forge a partnership. With the participation of my doctoral student, Mirela Donato Gianeti, we investigated whether the formula also protects against major climatic variations, and the result was very positive,” explained Campos.

Thanks to the vegetable extracts, the skin of the volunteers was not damaged during either the peak summer season or the winter. Their skin also remained undamaged under conditions of abrupt temperature change.

During the trial, the researchers also evaluated how the cream felt (tactile perception) to the volunteers. This sensitivity, explained Campos, is lost on aged skin.

“The formula improved moisture and skin barrier function, or in short, it reduced the water loss in the most superficial layers. But this resulted in an improved tactile perception because it gave skin a healthy appearance,” she said.

According to Campos, the formula is ready to be commercialized, but there still has been no contact with sector companies. Part of the study was published in the Journal of Investigative Dermatology.

Protecting DNA

Tests conducted with mice showed that the product developed at USP Ribeirão Preto reduced the levels of p53 and caspase-3, genetic markers that indicate cellular damage caused by radiation. “There was lower production of the metalloproteinase enzyme, which destroys collagen and leaves skin flaccid,” explains Campos.

In a second stage, similar tests were conducted with human volunteers using a real-time evaluation of the cream’s activity through biophysics techniques and skin images. The researchers also used a technique called reflectance confocal laser scanning microscopy, which can detect cellular alterations without the need for biopsies. 

“We observed deep moisturizing and an improvement in skin appearance for about 8 hours. It also significantly improved the skin barrier function and skin texture,” she explained.

Confocal microscopy analysis has not yet been conducted, but according to Campos, the scientists have determined that the product increased the thickness of the granular layer of the skin. This increased thickness could be associated with greater stimulation of cellular renovation.

At every stage, the tests included not only the complete formula but also versions that had only the sunscreen component and one of the study’s active ingredients. “We wanted to evaluate the benefit of each and the advantages of using the complete formula,” the researcher explained.

A combination of filters with red marine algae led to the greatest reduction in the presence of p53 and caspase-3, thus demonstrating that this formula was the most effective at preventing cellular damage. The combination with Ginkgo biloba was the formula that had the best effect on the skin barrier function.

The formula that contained only filters and vitamins increased water loss in the superficial layer compared with the other formulas. According to the researcher, this water loss is most likely related to the increase in cellular renovation stimulated by vitamins A and C. “For this reason, it is important to add vegetable extracts to compensate,” she stresses.

The greater the water loss, the more fragile and sensitive skin is. This greater fragility and sensitivity not only facilitates the penetration of ultraviolet light but also favors diseases such as contact dermatitis or topical eczema.

According to the researcher, the complete formula best moisturized the skin and enhanced the skin barrier function, improving the appearance of the skin and reducing wrinkles and roughness. However, she warns that this product is made for day-to-day use and not for periods of intense sun exposure, such as time spent at the beach or pool.

“Solar radiation accelerates cellular proliferation. It is the organism’s way of trying to defend itself, leaving the skin thicker. But this occurs in such a rapid manner that in order to avoid DNA damage it occurs after apoptosis or programmed cellular death,” she explains.

For intense sun exposure, she adds, a sunscreen formula should contain as many antioxidant substances, such as Ginkgo biloba and vitamin E, as possible.