Cosmetics additive may accelerate aging process in human cells

Berkeley, Calif. -- A new study says that an additive commonly found in cosmetics may inhibit the activity of sirtuins, enzymes associated with lifespan control in yeast and other organisms.

According to the study, which was carried out by a research team at the University of California, Berkeley, and was published online last month in the journal Public Library of Science, found that in lab tests, dihydrocoumarin (DHC), a compound found naturally in sweet clover and synthetically manufactured for use in foods and cosmetics, inhibited the activity of Sir2p, a sirtuin found in yeast, and SIRT1, a sirtuin found in humans.

Increased sirtuin activity is known to increase longevity in yeast, roundworms and fruit flies. The opposite effect in yeast has also been shown: When the sirtuin enzyme is either deleted or reduced, the lifespan decreases by as much as 30 percent. The study notes that though research on sirtuins and longevity have not been done in humans, there is reason to suspect that sirtuins may play a role in the aging process of human cells.

The researchers also tested the role of DHC in apoptosis, a process that causes a cell to die. They exposed DHC to human white blood cells and found that increasing concentrations of the compound led to increases in cell toxicity, apoptosis and the stability of p53, a tumor-suppressing protein associated with apoptosis.

The researchers say their study “raises some concern about the potential effects of DHC on humans,” but add that as yet there is no evidence that exposure to DHC in the diet accelerates the human aging process.