The ritual of slathering on sunscreen to ward off the sun's ultraviolet rays could soon give way to the simple act of swallowing a tablet. That's because researchers have found the secret behind a natural sunscreen made by coral of the Great Barrier Reef.
How coral survive the harsh tropical sun in their shallow water habitats had been a mystery until recently. Then researchers discovered the source of coral's protection: a compound made by algae living inside them. The coral transforms the compound into a natural sunscreen to protect both itself and the symbiotic algae.
"Not only does this protect them both from UV [ultraviolet] 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," said Paul Long, senior lecturer at the Institute of Pharmaceutical Science at King's College London.
The fact that the protection can be acquired through eating provides hope for human sunscreen protection in pill form. Long and his colleagues say they have begun to uncover the genetic and biochemical processes behind the compound and are looking to re-create it synthetically.
"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 said.
Coral's natural sunscreen also might help create UV-resistant crops that can support agriculture in developing countries. The plants already are capable of playing the role of algae in sunscreen production, researchers say, so they just need to figure out how to give plants the other half of the biochemical equation found in coral.
"If we do this in crop plants that have been bred in temperate climates for high yield but that at present would not grow in the tropics because of high exposure to sunlight, this could be a way of providing a sustainable nutrient-rich food source, particularly in need for Third World economies," Long said.
Another urgent area of the research concerns whether corals can survive climate change. Rising sea temperatures have led to loss of the symbiotic algae, which in turn can lead to the death of coral. Long and his colleagues want to study how the coral deals with light at higher water temperatures.
The British researchers collected the coral samples with Walter Dunlap from the Australian Institute for Marine Science and Malcolm Shick from the University of Maine.