Donna Zhang, Ph.D., Georg Wondrak, Ph.D.
University of Arizona
NIEHS grantees have discovered that a compound found in the natural food additive annatto prevents the formation of cancer cells and skin damage from ultraviolet (UV) radiation in mice. The compound prevents UV skin damage by inducing cells to make protective antioxidants and repair factors that prevent cancer cells from forming.
Annatto is often used as a yellow or orange food coloring and is consumed around the world. The researchers studied bixin, a bright reddish-orange compound found in annatto. After injecting a group of mice with bixin and exposing these mice and a control group to UV radiation, they found that the mice receiving bixin experienced much less severe skin sun damage than the control mice. Because studies had suggested that nuclear factor-E2-related factor 2 (NRF2) could play a role in protecting cells from sun damage, the researchers also examined bixin’s protective effects in mice with and without Nrf2. Bixin only showed its protective effects in the mice expressing Nrf2, confirming the NRF2 dependence of bixin-based cell protection.
Experiments with cultured human skin cells also showed that bixin activates a NRF2-dependent protective response in cells. Since annatto is approved by the Food and Drug Administration as a safe food additive, the researchers expect that future clinical trials necessary to test bixin would require fewer rounds of testing.
Citation: Tao S, Park SL, de la Vega MR, Zhang DD, Wondrak GT. 2015. Systemic administration of the apocarotenoid bixin protects skin against solar UV-induced damage through activation of NRF2. Free Radic Biol Med. 89:690-700.