A latest discovery in regards to the structure of melanin has brought scientists one step closer to developing a latest, potentially ultra-protective sunscreen derived from a biological substance present in nearly all organisms. Researchers from McGill’s Department of Chemistry, in collaboration with The Ohio State University and the University of Girona, have announced a significant advance in understanding the basic structure of melanin and one among its components that turns light into heat, protecting the body from sun damage.

Melanin, the pigment that provides humans their skin, eye, and hair color, is the body’s first and best natural defense against the sun’s harmful rays. Cosmetics firms have long tried to harness the protective powers of natural and artificial melanin to be used in chemical sunscreens and other personal care products. For instance, melanin could, in theory, be used to provide a radiation barrier that augments skincare products by matching a more diverse range of natural skin tones. But melanin is so notoriously unstable and difficult to review that, up to now, scientists haven’t been in a position to see what it looks like on the molecular level, leading to a slow, trial-and-error approach to its potential use in personal care products.

As we gain a greater understanding of the structure of melanin, we should always give you the chance to predictably make alternatives that perform higher than what’s currently available.”

Jean-Philip Lumb, one among the lead authors of the paper

The study found that the melanin component converted light into heat from all wavelengths, spanning the ultraviolet to the infrared, offering a broad spectrum of protection. The molecule was also remarkably small, which the researchers say has practical advantages since the variety of atoms needed to supply this level of sun protection is fewer than anything reported so far. “We have taken a significant step forward in understanding a latest mechanism for the way melanin can function a sunscreen,” Lumb said.

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Journal reference:

Wang, X., et al. (2023) Indole-5,6-quinones display hallmark properties of eumelanin. Nature Chemistry. doi.org/10.1038/s41557-023-01175-4.