As far back as Mesopotamia and Ancient Egypt, scholars have recorded and cataloged natural medicines. Most of these treatments were sourced from plants found on land because it was impossible for humans to effectively explore the oceans. However, as medicine progressed and sought to find treatments to more diseases, it became necessary to broaden the search beyond the shoreline.
Up until the advent of SCUBA equipment, it was often difficult for scientists to explore the ocean. As noted by William Fenical, a chemist who scours the ocean searching for sources of new drugs, in a Nature article, “until about 1970, no one even thought of the ocean.” Its depths are still largely unexplored and contain many organisms, particularly stationary and slow-moving ones, that produce unique chemicals as a means of self-defense. On the surface, it may appear that they are merely producing toxins. However, the poisonous effects of these chemicals can be harnessed for medical purposes, with properties ranging from pain management to Alzheimer’s treatment. Because of this, the ocean has a unique potential as a source of medicine and is frequently referred to as ‘the 21st century’s medicine cabinet.’
A main area of promise is the development of new cancer drugs. Yondelis, approved by the FDA in 2015, was derived from a creature called a tunicate, also known as a sea squirt. In addition, one of the first prominent chemotherapy treatments was derived from sea life. Cytarabine, also known as Cytosar-U, was originally isolated from a sea sponge in 1959. After showing promise in lab experiments, it was developed into a drug that became a common treatment for leukemia and lymphoma. In fact, Cytosar-U is now on the WHO List of Essential Medicines, which provides guidelines for medications needed to provide comprehensive health care. Although Cytosar-U proved to be one of the ocean’s greatest success stories, there has not been a massive onslaught of new drugs with marine origins. Many other promising compounds, like eleutherobin, an anticancer agent sourced from corals, faced slow research because they were difficult to collect and synthesize. By 2012, only three drugs from marine sources had been approved by the FDA, and only one had been approved by the EU. Even with these limited numbers of approved treatments, there are still some promising drugs awaiting or entering clinical trials.
One of these candidates is bryostatin 1, isolated from a marine pest called the brown bryozoan. It has shown potential as an immunotherapy drug for cancer, HIV, AIDS and Alzheimer’s disease, but development has been slowed by limited supply, according to a Stanford News Service interview with principal investigator Paul Wender, who stated “we started to realize that clinical trials a lot of people were thinking about were not being done because they didn’t have enough material.” It is wildly inefficient to gather this drug from natural sources: in one case, scientists collected only 18 grams of bryostatin 1 from 14 tons of bryozoans. In addition, bryozoans only produce bryostatin in very specific environments, meaning that some populations are useless for isolating this compound. Research ground to a halt simply because there was no way to produce enough to go around. Fortunately, there has been a breakthrough in the production of bryostatin 1. Wender’s lab managed to develop a process to synthesize the compound with a whopping 4.8 percent yield, thousands of times more efficient than extracting bryostatin from its natural source. With this development, the lab hopes to eventually synthesize 20 grams of the compound per year, enough to treat up to 20,000 cancer patients, giving Bryostatin 1 a fighting chance to become a useful drug.
The onslaught of interest in ocean-derived drugs has increased just as the environments this research relies on become increasingly threatened by climate change. The shallower coastal regions that are most easily explored by scientists are rapidly declining: it has been found that up to 30 percent of coral reefs worldwide have already degraded. Reefs are critical to marine biodiversity, with about 25 percent of species found in or around coral reefs. The breakdown of these fragile and diverse ecosystems means that many species of marine life will go extinct or near extinction before scientists even know they exist. For scientists trying to take full advantage of nature’s medicine cabinet, this disappearance adds another layer of urgency to their search. As the ecosystem begins to die, so does the chance of finding new treatments. The preservation of marine environments is critical ecologically, but when viewed from a medical perspective becomes an even more pressing issue.