Coral reefs are valued for their beauty, tourism value, and ecosystem services, such as nursery provision for fish and barriers against storm damage, and are one of the most diverse habitats on earth. Recently, coral reefs have also been described as “the medicine cabinets of the 21^st century” due to the chemicals they produced that are used in modern medicine.

Natural Medicines

Scholars have recorded natural medicines since the times of Ancient Egypt. Most of these treatments were provided by plants found on land, as it was not possible for ancient humans to access and explore the oceans efficiently. However, as medicine and technology progressed and the need to find treatments for more complex diseases increased, it became necessary to search for natural medicines beyond the coast.

Although the depths of the ocean remain largely unexplored, the invention of SCUBA equipment allowed chemists and scientists to scour the ocean in search of new sources of drugs. Stationary and slow-moving organisms are not able to escape predators, and as such many of these organisms have developed unique chemicals to defend themselves. Although it may seem that these organisms produce simple toxins, the poisonous effects of these chemicals may be utilized for medicinal purposes. Prominent uses of these chemicals in medicines are for the use of pain management, Alzheimer’s disease treatment and heart disease treatment. Some of the chemicals are produced to help fight infection, and other to protect the territory of the stationary marine organisms by stopping other organisms’ cells from dividing and taking over – similar to how drugs are used to stop cancer from spreading.

Compounds from sea sponges are being used to not only provide antibiotics and drugs for cancer treatment, but their skeletons are being studied to develop ways to grow bone for grafting and dental implants. There is potential in deep-sea corals to produce medicines – one sea fan contains powerful anti-inflammatory chemicals, some soft corals have potential anti-cancer and ant-viral compounds, and bamboo corals may also be useful for bone grafting.

Treating Cancer

Developing cancer drugs poses a great challenge, as cancer cells are very similar to human cells, and it is difficult to kill the one, but not the other. Current chemotherapy treatments are able to kill cancer cells, but are not selective enough and also target healthy human cells, therefore resulting in nausea, vomiting and hair loss. Cancer research is thus focused on developing drugs that successfully kill cancer cells, without harming the patient too much.

Corals, sea squirts and sea sponges potentially hold the promise to develop new cancer drugs. One of the first prominent chemotherapy treatments was derived from a marine organism. Cytarabine, a drug listed on the World Health Organisation’s List of Essential Medicines, was originally isolated from a sea sponge back in 1959. After showing promising results in lab experiments, it was developed into a drug for the treatment of leukemia and lymphoma. Yondelis is a drug approved by the FDA in 2015, and was derived from a sea squirt. Many other promising compounds, such as eleutherobin – an anticancer agent sourced from corals – faced slow research due to difficulty in collecting and synthesizing the compounds. There has not been a large surge of drugs from the ocean, and by 2012 only three drugs from marine origins have been approved by the FDA, and only one was approved by the EU. Even so, there are still some drugs awaiting clinical trials.

One of these candidate drugs is called Bryostatin 1, and is isolated from a marine pest called brown bryozoan. This bushy organism colonizes any available surface, including artificial structures and vessel hulls. Bryostatin 1 has shown potential as a drug for cancer, HIV, AIDS and Alzheimer’s disease, however research and development has been slowed down due to limited supply. Bryozoans only produce Bryostatin 1 under certain conditions, and large masses of the organism might not produce a single gram.

Researchers are continuously extracting samples from deep-sea sponges and corals, hoping that at least one species could provide chemicals that are tougher than the cancer cells grown in laboratories. Teams of scientists are traveling to polluted and pristine waters to collect sea life from the deep sea, using a submarine with mechanical arms to collect sponges and corals that often have never been seen before. The National Cancer Institute estimates that approximately 65% of all cancer drugs come from land, plants and marine life, however it takes thousands of lab tests to find one promising lead.

Ocean Medicines and Climate Change

The increase in interest in drugs produced by marine life coincides with the increased pressure on marine ecosystems due to climate change and unsustainable harvesting of resources. The biodiversity occurring in shallow coastal regions that are easily explored by scientists is rapidly declining. Coral reefs, a habitat that consist of many stationary and slow-moving organisms that produce unique chemical compounds, are becoming degraded. The breakdown and loss of these habitats means that many marine life species will go extinct or nearly extinct even before scientists are able to research them or know of their existence. As  marine ecosystems become degraded and begin to disappear, so does the chance of finding new medicines. Although the protection of marine ecosystems is crucial from an ecological perspective, it becomes even more urgent when the benefit to medical research is considered.

Protecting Sensitive Habitats

The medical promise of sponges, corals and algae is a valuable driving force behind efforts to conserve these habitats, which are not only threatened by climate change, but also by overfishing, pollution, and oil and gas extraction in the ocean.

It is important to note that scientists and medical researchers are not planning on harvesting large amounts of corals and marine organisms in order to produce these drugs that have the potential for cancer treatment. Scientists collect small samples, which are taken to laboratories where it is then attempted to replicate the promising properties and produce similar compounds. It would not be economically or ecologically realistic to exploit coral reefs, due to the intrinsic value they hold to humans.

The current medicinal discoveries are only scratching the surface of the medical benefits the ocean may hold. More studies are being conducted, which has the potential to lead to a clearer understanding of diseases and health benefits of marine life. It is therefore important to protect the ocean, because a polluted oceanic environment will not be able to provide the necessary medical breakthroughs so desperately needed by humanity.