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Thursday, December 09, 2004
Medicines from coral reefs
By Henrylito D. Tacio
Regarding Henry
CORAL reefs could be the sources of many new medicines in the 21st century. "Marine sources could be the major source of drugs for the next decade," says Dr. William Fenical, a natural products chemist at the Scripps Institution of Oceanography in La Jolla, California.
Like the tropical rain forests, the reefs hold considerable untapped potential in the science of medicine. 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. Coral reefs also produce a natural sunscreen, which is now being marketed to sell as a sunscreen to humans in America. 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.
"Half the potential pharmaceuticals being explored are from the oceans, many from coral reef ecosystems," estimates the US State Department.
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 U.S. National Cancer Institute (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," Dr. Colin reports.
"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.
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. Chemicals from sea sponges collected off the coast of Florida have been used in developing a new drug, Ara-C, used to treat acute myelocytic leukemia and non-Hodgkin's lymphoma. The antiviral drug called Ara-A is used for the treatment of herpes infections.
Unfortunately, the future of our coral reefs is in jeopardy. Ten percent of the world's coral reefs have already been seriously degraded and a much greater percentage is threatened, particularly in areas adjacent to human populations. If this decline continues, there could be a significant loss of the world's reefs and their resources,
The Philippines, home to over 400 local species of corals, which is more than what is found in the famous Great Barrier Reef of Australia, is not spared from this environmental problem.
An analysis of more than 600 data sets showed that "excellent" reefs (live hard and soft coral cover above 75%) have reduced from 5.3% to 4.3% since the late 1970s. If hard corals alone are considered, only 1.9% of the reefs can be called "excellent," with average hard coral cover on all reefs at 32.3%, whereas it used to be much higher.
The decline is thought to be due primarily to destructive human activities. "Many areas are in really bad shape due largely to unwise coastal land use, deforestation and the increasing number of fishermen resorting to destructive fishing methods," says marine biologist Porfirio M. Alino of the University of the Philippines Marine Science Institute.
Destructive fishing methods--ranging from dynamite blasts to cyanide poisons--are destroying vast areas of reef. Fishermen blast reefs with dynamite to stun the fish. When fish float to the surface, fishermen scoop up large quantities at once. Heavily dynamited reefs produce only 2.7 to 5 metric tons per square kilometer per year compared to 30 metric tons for healthy reefs.
The damage caused by dynamites to reefs goes beyond the shattering impact of the explosion itself. After a blast, algal growth quickly smothers the coral because the shoals of grazing fish that would normally keep it under control have been decimated.
Although illegal in most countries, dynamite fishing is still widely practiced in 40 countries because of economic need and poor enforcement of laws prohibiting it. In the Philippines, explosives have damaged an estimated one-sixth of reefs since 1945.
In recent years, the phenomenon called bleaching has also threatened the country's sensitive coral reefs. From 1997 to 1998, massive coral bleaching--in which corals turn chalky white--was reported in Masinloc, Zambales; Bolinao, Pangasinan; Bacuit Bay, El Nido, and Coron Islands in Palawan; and Puerto Galera, Oriental Mindoro.
The whitening of corals, marine experts explain, is from the loss of zooxanthellae, an organism found in the tissue of polyps (a tiny flower-like animal connected by a membrane that covers the coral rock), exposing the coral's calcium component and usually causing its death. The phenomenon has been traced to global warming.
Also contributing to the destruction of coral reefs in the Philippines are sedimentation from erosion of soil from deforestation; the quarrying of coral reefs for construction purposes; pollution from industry, mining, and municipalities; and coastal population growth.
Touted to be the "rainforests of the sea," coral reefs are habitats for rare species, including some 488 species of corals, 971 species of benthic algae, and 2,000 species of fish. More than half of the fish consumed by Filipinos depends on coral reefs.
Coral reefs have been around for about 200 million years, and have survived eons of storm-induced damage and sea animal predation. Unfortunately, their survival in this century is less certain.
Let us then help conserve and protect our coral reefs. The words of Dr. Rafael D. Guerrero III of the Philippine Council for Aquatic and Marine Research and Development, come in handy: "We are the stewards of our nation's resources; we should take care of our national heritage so that future generations can enjoy them. Let's do our best to save our coral reefs. Our children's children will thank us for the effort."
(December 9, 2004 issue)
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