https://www.forbes.com/sites/carmendrahl/2017/02/01/nature-is-the-inspiration-for-this-new-crop-of-sunscreen-candidates/#519d44516fd0
Sunscreen isn’t just for summer — everyone from skiers to the skin-conscious slathers on the stuff. Now, a research team has used all-natural molecules as inspiration for new sunscreen candidates. They say their compounds dissipate ultraviolet (UV) light in a new way. If future tests pan out, their hope is the molecules could go some of the way toward improving sunscreen technology.
People use sunscreen to prevent painful sunburns and to slow down signs of skin aging such as wrinkles. They also use it to protect against skin cancer, though experts will tell you that compared to other skin cancers, the evidence for sunscreen protection against melanoma isn’t as strong.
Sunscreen ingredients have clear benefits, but they aren’t perfect. Here are just a few examples: One of the better ingredients on the market to protect against UVA rays, avobenzone, needs stabilizing additives to keep it from breaking down and losing effectiveness in sunscreen formulations. An older ingredient, para-amino benzoic acid (PABA), is seldom used today because it sometimes prompts allergic reactions that irritate people’s skin. (PABA occurs naturally in bacteria and plants — that’s an aside to point out that something natural isn’t automatically the solution to every problem.) And the sunscreen component oxybenzone has been shown to damage coral reefs, prompting Hawaii officials to recommend other ingredients to ocean-goers.
Which brings us to today’s study. The ocean teems with life that produces natural sunscreens. Marine algae, for example, make a family of molecules called mycosporine-like amino acids. These specialized amino acids are appealing to manufacturers, but they are difficult to come by from natural sources and have a tendency not to stay put where they’re applied.
Diego Sampedro and his colleagues wondered if they could use these marine sunscreens as a starting point, and make something that would be easier to formulate into sunscreen lotion while having even better UV-ray-dissipating properties. Sampedro is a chemist at the University of La Rioja in Spain, and his study, conducted in collaboration with dermatologists and other chemists, appears in the journal Angewandte Chemie.
The chemists started by using software to determine what pieces of the marine sunscreens’ chemical structures were essential for UV-ray-dissipating activity. They also calculated what would likely happen to the resulting compounds when hit with UV light.
It’s helpful at this point to know what goes on, chemically speaking, when you slap on some SPF. The “physical sunscreens” such as titanium dioxide and zinc oxide reflect, scatter, and absorb skin-damaging ultraviolet light rays. Meanwhile, so-called “chemical sunscreens” contain compounds such as octinoxate, with alternating single and double bonds. This arrangement helps the molecules absorb high energy UV rays and release lower-energy rays that can’t do as much damage to skin. (“Chemical sunscreen” is a confusing name to chemists like me, since all sunscreens contain chemicals.)
What’s interesting is that the researchers didn’t see either of those modes of action in their computer simulations. Instead, their calculations suggest a different mechanism. Specific pieces of their sunscreen candidate molecules appear to move when dissipating UV light energy. The team made some promising candidates in the lab and demonstrated that they did indeed absorb UVA and UVB light in commercial sunscreen formulations.
The team must conduct additional laboratory tests that confirm their new mode of action is truly happening. They also would need to conduct many tests to ensure safety and effectiveness when this sunscreen is used on human skin, or in paints or clothing fibers. New sunscreen ingredients have a difficult path to approval in the U.S. — it’s led to much wrangling between the Food and Drug Administration and the chemical and cosmetic companies that make sunscreens. European and Australian sun-seekers have more sunscreen ingredient options, though the jury’s still out on whether new ingredients will make a dent in the continually increasing rates of melanoma.
I’m reluctant to say that any one new UV-ray-dissipating mechanism is the answer to the world’s sun protection needs. In my line of work, I’ve come across drug candidates that excite chemists because of their elegant new modes of action, only to learn later that they don’t have blockbuster performance in the real world. It’s going to take a lot of new approaches to beat this problem. For now, the best way to think about sunscreen is that it’s not a license to bask in direct sunlight indefinitely. Slather on plenty of sunscreen that protects against UVA and UVB rays, but also cover up, seek shade, and reapply frequently.
