The ocean deep holds untapped potential when it comes to new therapies that could treat diseases like cancer and Alzheimer’s. But climate change and pollution threatening marine ecosystems means scientists and drugmakers are working against the clock to find them.
In the 1950s, a Carribean sea sponge species changed medicine forever: In the sponge, scientists discovered and isolated a molecule that they learned could slow down replication of viruses. Back in the lab, this discovery became the basis for the development of azidothymidine, or AZT, one of the most effective HIV drugs. Later, it would be used by drugmakers to treat SARS and MERS, and even become the basis of remdesivir, one of the few efficacious drugs in the treatment of COVID-19.
Then, there is the story of a compound found in the soft coral Cladiella australis in the western Indo-Pacific. A recent study showed that this compound, 4-PSB-2, improves impaired memory retrieval and reduces excessive inflammatory response in the brains of mice with Alzheimer’s biomarkers, indicating that it could lead to a viable treatment for the neurogenerative disease.
Other researchers have discovered that some coral reefs contain powerful anti-inflammatory chemicals, and in those, they suspect, could be potential anti-cancer and anti-viral properties.
The good news, according to Aaron Hartmann, a marine biologist and Research Associate in Organismic and Evolutionary Biology at Harvard University, is that the sea may hold countless molecules like this that have yet to be discovered — molecules that could treat Alzheimer’s symptoms, serve in the frontlines of the fight against cancer, or end the next viral pandemic.
The bad news is that in some cases, scientists and drugmakers may be running out of time to find them. Marine biodiversity is in crisis for all kinds of reasons, most notably climate change, pollution and other human-caused activities, like overfishing: When one species is depleted, entire vast and complex marine ecosystems can be thrown out of balance.
“Coral reefs are in trouble,” said marine scientist Dr. Greg Stone. “Roughly speaking, one third of all the reefs in the world are in a state of very poor condition. Not completely dead, but very degraded. And another third is threatened to be that in that state. You’re left with about a third that are okay in the world right now — and that’s not good.”
While coral reefs encompass more biological diversity than a tropical rainforest and while a quarter of all marine species depend on them for survival, they already occupy less than one percent of the ocean floor.
Coral bleaching events – considered a global crisis and caused by increased ocean temperatures due to climate change and carbon pollution – are one of the main threats to coral. Plastic pollution also ranks high on the list: When coral comes into contact with plastic, its likelihood of disease increases from 4 percent to 89 percent.
Hartmann echoed Stone’s coral concerns: “We do fear that the loss of coral reefs is leading to the loss of potentially interesting drugs that we haven’t had the chance to discover yet,” he told Being Patient. “In general, we’re going to probably be losing a lot of potential drugs that could help us find the next breakthrough to treat the next pandemic, neurologic diseases or cancer. You know, these things that we don’t even know yet.”
“One of the reasons we find a lot of interesting chemicals on coral reefs is that they’re very, very, very old ecosystems,” he added, noting that reefs are hundreds of millions of years older than humans. “They have to fight a lot of different things in order to hold the ground and survive, which leads them to create lots of good defense systems, because they also don’t have a lot of physical structures to protect themselves. They also have functions that are pretty amazing for fighting viruses, for instance.”
One example is an experimental Alzheimer’s drug fresh off the seafloor, derived from extracts of brown algae. A Shanghai-based biotech startup, Green Valley Pharmaceuticals, received approval from the Chinese equivalent of the Food and Drug Administration (FDA) for their drug, oligomannate to treat Alzheimer’s patients. The drug is a sugar derived from seaweed or kelp and inspired by the holistic approach embedded within traditional Chinese medicine. Now, the drug is making its way through human clinical trials in 12 U.S. states.
Does this mean drug makers will have to put on their waders and start harvesting seaweed? Not quite: Once a medicinal molecule is pinpointed, Hartmann explains, it is then replicated in the lab: “You just need to find it once, essentially,” Hartmann explained. “Then once you know what its chemical structure is, you figure out how to produce it.”
If researchers and drugmakers find an effective molecule to treat a particular disease, Hartmann said, they’ll look at the family of said molecule — molecules similar terms of their chemical structure, but with slight variations. If one molecule is a known cancer drug target, and an effective one at that, the next question is: “What are the other molecules that are closely related to the other chemical, which may have anti-cancer properties that maybe are even better, or more potent or can be used to treat a slightly different disease?,” Hartmann said.
Discovering these potential human health solutions in the ocean and developing these drugs is no quick feat. “The pace of science at the level of developing drugs is relatively slow, it takes time,” Hartmann explained. “So, to give us that time, we need to preserve the ecosystems that we have, as best we can in the state they’re in now.”