Sunscreen pills from coral

By Dr. Ananya Mandal, MDAug 31 2011

Researchers have found that coral does not suffer from sunburn despite living in shallow water in tropical areas, because it is able to produce its own “natural sunscreen”. By studying the compounds which protect it from UV rays, researchers hope to develop a tablet which can protect human skin and eyes without the need for dark glasses or sun cream. Scientists from King's College London said the first sunscreen pill could be available within five years.

The tablet might have to be prescribed by doctors to prevent the risk of people overdosing, which could lead to vitamin D deficiency and cause weak bones. The researchers noted that coral converts compounds produced by algae living inside it to make a sunscreen which protects both the coral and the algae from sunburn. Fish which feed on the coral also gain protection from the sun, but the human digestive system wipes out the compounds before they can offer us any benefit.

But Dr Paul Long, who is leading the research, hopes to engineer the compounds in the lab so that they survive long enough in our bodies to enter the bloodstream and offer us some level of protection. He said, “We are very close to being able to reproduce this compound in the lab, and if all goes well we would expect to test it within the next two years.” Long leads a three-year research project, financed by the British government, focused on sun-shielding compounds in Acropora microphthalma coral.

“What we have found is that the algae living within the coral makes a compound that we think is transported to the coral, which then modifies it into a sunscreen for the benefit of both the coral and the algae,” Long said in a statement from King's College, which issued a news release and video about the research. “Not only does this protect them both from UV damage, but we have seen that fish that feed on the coral also benefit from this sunscreen protection, so it is clearly passed up the food chain.”

Because Acropora microphthalma coral is endangered, the scientists first must create a synthetic version of the coral compounds, which could be tested on human skin samples. Long has suggested scientists might find a ready supply in excess skin discarded by plastic surgeons after tummy tucks. Only after scientists learn how the compound affects skin cells could they then begin developing a pill that would protect skin throughout the body, as well as the eyes, which also are sensitive to the effects of UV light.

Long's longtime collaborators are J. Malcolm Shick, a marine sciences professor at the University of Maine in Orono, and Walter Dunlap, a marine research scientist at the Australian Institute for Marine Science. In 1986, Dunlap reported the discovery of UV-absorbing sunscreens in shallow-water coral. The three have published several papers on the biochemical processes and genes responsible for Acropora's response to solar radiation, as well as the phenomenon of coral bleaching. Long also said a long-term goal of the research project is to help make crops in Third World countries more able to withstand strong UV light.

Coral is an animal which has a unique symbiotic partnership with algae that lives inside it - the algae use photosynthesis to make food for the coral and the coral waste products are used by the algae for photosynthesis. Because photosynthesis needs sunlight to work, corals must live in shallow water, which means they are vulnerable to sunburn. Bleaching occurs when a rise in sea temperature (by 2-3 degrees more than the summer average) means the algae is lost from the coral tissues, and if the relationship between algae and coral is not re-established, the coral may die.