CORAL reefs could be the sources of many new medicines in the 21st century.
"Marine sources could be the major source of drugs in the coming years," says Dr. William Fenical, director for marine biotechnology and biomedicine at the Scripps Institution of Oceanography in La Jolla, California.
"Many coral reef species produce chemicals like histamines and antibiotics used in medicine and science," reports The Nature Conservancy, an organization whose mission is to preserve plants, animals and natural communities by protecting the lands and waters needed for their survival.
Already, the US National Cancer Institute (NCI) has been screening each year about 1,000 species of oceanic invertebrates and plants, including sea slugs, sea squirts, sponges, and several other denizens of coral gardens.
"Coral reef plants and animals are important sources of new medicines being developed to treat cancer, arthritis, human bacterial infections, heart disease, viruses, and other diseases," says the US National Oceanic and Atmospheric Administration (NOAA). "Some coral reef organisms produce powerful chemicals to fend off attackers, and scientists continue to research the medicinal potential of these substances."
Coral reefs are among the most biologically diverse ecosystems on earth. Second only to tropical rain forests in the number of species they harbor, they are sometimes called the "rainforests of the sea."
Although coral reefs only occupy about 0.07 percent of the ocean floor (an area roughly the size of Texas), they are home to as many as one quarter of the world's marine species.
As a matter of fact, coral reefs hold considerable untapped potential in the science of medicine. For centuries, coastal communities have used reef plants and animals for their medicinal properties. In the Philippines, for instance, giant clams are eaten as a malaria treatment.
"Unique medicinal properties of coral reef organisms were recognized by Eastern cultures as early as the 14th century, and some species continue to be in high demand for traditional medicines," observes Dr. Andrew Bruckner, a coral reef ecologist in the US National Marine Fisheries Service's Office of Protected Resources in Silver Spring, Maryland.
In China and Taiwan, tonics and medicines derived from seahorse extracts are used to treat a wide range of ailments, including sexual disorders, respiratory and circulatory problems, kidney and liver diseases, throat infections, skin ailments, and pain.
In Japan's reefs, one of the most studied coral coasts in the world, there is a chemical called kainic acid, which is used as a diagnostic chemical to investigate Huntington's chorea, a rare but fatal disease of the nervous system. Sea whips, a type of soft coral found throughout the Caribbean may hold the key to promising new painkillers.
Other coral chemicals have proved useful in research on arthritis and asthma. Australian researchers have developed a sun cream for a coral chemical that contains a natural "factor 50" sun block.
Also, the porous limestone skeleton of coral is now being tested as bone grafts in humans.
"If used properly, the reefs of the entire world can better serve humans with medicine rather than with food," some researchers claim.
In an article, which appeared in Reef Research, Dr. Patrick Colin, a marine biologist, clearly described the hopes that had led him to spend the 1990s collecting marine samples in the Pacific for the NCI.
"Over the years, the NCI has been screening terrestrial plants and marine organisms worldwide for bioactivity against cancer and Acquired Immune Deficiency Syndrome (Aids), and has come up with a number of hot prospects, a number of which are in clinical trials," he wrote.
According to the US State Department, half the potential pharmaceuticals being explored today come from the oceans, many from coral reef ecosystems.
The NOAA reports that marine biotechnology has become a multibillion industry worldwide, "with a projected annual growth of 15 to 20 percent during the next five years."
"The marine environment became a focus of natural products drug discovery research because of its relatively unexplored biodiversity," says the book, From Monsoons to Microbes.
After all, the ocean contains more than 200,000 described species of invertebrates and algae but this number is but a small percentage of the total number of species that have yet to be discovered and described.
According to the book, marine sponges are among the most prolific sources of diverse chemical compounds with therapeutic potential.
Of the more than 5,000 chemical compounds derived from marine organisms, more than 30 percent have so far been isolated from sponges.
Chemicals with therapeutic potential can also be extracted from bryozoans, ascidians, mollusks, cnidarians and algae. Several strains of phytoplankton have been discovered to be exhibiting antibacterial and antifungal properties.
Since the mid-1970s, private and government-funded institutions from the United States and other industrialized countries have devoted varying levels of effort to the discovery of marine-derived pharmaceuticals.
Among the recent discoveries include: bryostatin, a polyketide isolated from the bryozoan Bulgaria neritina with both anticancer and immune modulating activity; ecteinascidin 743, a complex alkaloid derived from the ascidian Ecteinascidia turbinate; and disodermolide, a polyketide isolated from deep-water sponges of the genus Discodermia.
Despite the emphasis on identifying new anticancer compounds, marine natural products have also been found to have other biological activities, including mediation of the inflammatory response.
In addition, a number of marine-derived compounds have been discovered with antiviral and antifungal activity.
Meanwhile, the use coral in bone grafts is spreading rapidly. Pieces of coral set into a fracture act as a scaffold around which the healing can take place. The implant eventually disappears, absorbed by the new growth of bone. Rates of rejection are much lower than with artificial grafting materials.
"We can expect future medical benefits from chemical compounds in coral reef species and ecosystems," says the World Wide Fund for Nature. "Just as with tropical forests, we may find the answers to medical problems in the coral reefs, as long as we can preserve them and keep them healthy."