Formulating Ferulic Acid for Antioxidation

By: Katie Schaefer, C&T magazine

Posted: May 27, 2010, from the June 2010 issue of Cosmetics & Toiletries.

Recent industry market reports suggest two trends are here to stay—antiaging and naturals. Consumers demand skin care products that offset aging by preventing solar and environmental oxidative damage; in addition, they now expect these products to do so naturally.

Joseph Laszlo, PhD, lead scientist for the US Department of Agriculture’s (USDA) Biocatalytic Functionalization of Plant Lipids project, and his team have developed a process through which vegetable oil, in this case soybean oil, can be given antioxidant and UVA/UVB protective capabilities. FSG (INCI: Feruloyl Soy Glycerides)^a was developed by swapping out the fatty acids in vegetable oil with ferulic acid, and while the team initially investigated this material’s sun protective abilities, it is now focused on its antioxidant benefits.

Feruloyl Soy Glycerides
Nearly 10 years ago, Laszlo and his team were charged with finding new uses for vegetable oil, possibly for skin care, at which point the team came up with the idea of replacing one of the fatty acid groups with ferulic acid. “Ferulic acid has been studied for decades for its antioxidant capability,” noted Laszlo. However, he also conceded that ferulic acid is both difficult to formulate with and unstable. The team therefore put ferulic acid into soybean oil to stabilize it and improve its usability; first, however, the team had to make it soluble in vegetable oil.

“To make ferulic acid soluble in vegetable oil, we first obtained the ethyl ester of ferulic acid, as ferulic acid is a carboxylic acid like many fatty acids available,” said Laszlo. At the right temperature, both ferulic acid and soybean oil are liquid and miscible. So, a combination of ferulic acid ethyl ester with soybean oil was passed over a bed of immobilized enzyme. “The enzyme is called a lipase, and this lipase exchanges fatty acids for the ferulic acid on the glyceryl backbone of the vegetable,” explained Laszlo. The end product reportedly exhibited both antioxidant and photoprotective capabilities. Since the material is not approved by the US Food and Drug Administration (FDA) as a sunscreen, its application as such is limited; therefore, research has shifted toward its ability to protect against oxidation.

Antioxidant Capability
Laszlo and his team conducted a number of assays to assess the material’s antioxidant activity and when it performed well, a further assay was carried out by taking soy glyceride and incorporating it into model membranes—phospholipid membranes that surround the cells. “We found that the material incorporated into the membranes without affecting their physical barrier/stability. It did not adversely change [their] integrity.”