Coral reefs could provide the medicines of tomorrow

Posted: 28 April 2009

Author: Henrylito D. Tacio

Recent research indicates the huge potential of coral reefs for medical science. But, says Henrylito Tacio that potential is being threatened by human pressures on the reefs, already advanced in his own country: the Philippines.

United States marine biologist Dr. Kent Carpenter, who has been diving in the country's oceans since the 1970s, considers the Philippines to be "the best place in the world for a marine biologist."

In terms of coral riches, he is certainly right. There are about 400 species of reef-forming corals in the country, comparable with those found in Great Barrier Reef of Australia. The Philippines has about 27,000 square kilometres of coral reefs; two-thirds in Palawan and the Sulu Archipelago.

A new species of damselfish, Pomacentrus sp., was found on the Great Sea Reef. © Helen Sykes/WWF
A new species of damselfish, Pomacentrus sp., was found on the Great Sea Reef. © Helen Sykes/WWF
A new species of damselfish, Pomacentrus sp., was found on the Great Sea Reef.© Helen Sykes/WWF
A single reef can support as many as 3,000 species of marine life. As fishing grounds, they are thought to be 10 to 100 times as productive per unit area as the open sea. Around 10-15 per cent of the total fisheries in the Philippines come from coral reefs, and up to 90 per cent of the incomes of small island communities come from fisheries.

"Coral reef fish yields range from 20 to 25 metric tons per square kilometre per year for healthy reefs," Dr. Angel C. Alcala, former environment secretary.

But what my physician friend doesn't know - and this may interest a lot of doctors, too - is that coral reefs are a vast source of medicines that could help humanity. In fact, they could be the major sources of many new medicines in the present century.

Ocean potential

"Marine sources could be the major source of drugs for the next decade," says Dr. William Fenical, an American natural products chemist at the Scripps Institution of Oceanography in La Jolla, California.

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 in the United States. 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.

Writing in Reef Research, Dr. Patrick Colin, a marine biologist, described the hopes that had led him to spend the 1990s collecting marine samples in the Pacific for the US 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 says.

"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.

Traditional cures

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.

Damaged coral reef
Damaged coral reef
This reef shows signs of erosion and bleaching. Photo © Ove Hoegh-Guldberg, University of Queensland.
Unfortunately, the future of the planet's coral reefs is in jeopardy. Ten per cent of the world's 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 is not spared from this problem. Nationwide surveys conducted from the 1970s to the 1990s found that only 4-5 per cent of the reefs were in excellent condition, 25-27 per cent good, 39-42 per cent fair, and 27-31 per cent poor.

"The general trend is negative for the coral reefs in the Philippines," the World Bank reported in a global survey. It found that the Philippines had "the most degraded reefs of all sampled countries." The analysis found that 98 per cent of coral reefs in the country were "at risk from human activities," with 70 per cent at high or very high risk.

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. Dr. Edgardo D. Gomez, director of the Marine Science Institute of the University of the Philippines at Diliman, agrees. "If asked what the major problem of coral reefs is, my reply would be 'The pressure of human populations'," he asserted.

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.

Henrylito Tacio is our Contributing Editor in East Asia.