Saltwater Cures

Biodiversity prospecting, or bioprospecting, is the exploration of natural resources for useful molecules, biochemicals, and/or genetic information. These discoveries are then developed into commercial products such as medicines. Approximately 25% of medicines are derived from naturally occurring compounds. Most of these compounds were originally found in terrestrial ecosystems. However, a growing number are now being found in our oceans.  

Earth’s oceans are incredibly diverse and still largely unexplored. Particularly promising for bioprospecting and drug development are the bioactive compounds (compounds that produce a biological response in cells and tissue) being discovered in ocean organisms. Marine invertebrates such as sponges, tunicates, ascidians, bryozoans, octocorals, mollusks, annelids, and echinoderms contain a plentiful and potent arsenal of chemicals. Aquatic plants and microorganisms are also a rich source of therapeutic agents.

Here are four marine-derived medicines.

Conus magus Richard Parker, CC BY 2.0

1. Ziconotide obtained FDA approval in 2004 as a powerful pain killer. It works by blocking N-type calcium channels which helps interrupt pain signaling between synapses. This unique mechanism of action makes the chemical incredibly effective – its potency is estimated to be 1000 times that of morphine! It also has the huge additional advantage that prolonged use does not lead to tolerance and addiction. However, ziconotide can only be administered intrathecally (into the spinal fluid) which currently limits its use to cases of severe and chronic pain. Today the compound is mainly taken as a synthetic molecule under the name Prialt. However, it was originally extracted from the sea snail Conus magus. This snail is a fish hunter found in the Red Sea and Indian ocean and the compound was discovered in the snail’s deadly venom. 

Acremonium CDC

2. Cephalosporins are a large group of antibiotics. The name comes from the marine fungus that the first cephalosporins antibiotic were extracted from – Cephalosporium acremonium. This aerobic mold was first discovered in 1945 off the coast of Italy. Early forms of the drug were effective mainly against gram-positive bacteria such as Staphylococcus and Streptococcus. These first generation drugs were used mostly for skin, soft tissue, and post-surgery infections. Decades of R&D have led to successive generations of cephalosporins that are also active against gram-negative bacteria. These later antibiotics are used in patients allergic to the more common antibiotic group Penicillins.

Tectitethya crypta Dr. Sven Zea, CC0, via Wikimedia Commons

3. Vidarabine was one of the first widely used antiviral drugs. The compound was originally isolated from the Caribbean sponge Tectitethya crypta and studied as a potential anti-cancer drug. However, in 1964 researchers discovered that it had a strong inhibitory effect on viral replication. In the 1970s and 1980s, it was widely used for the treatment of herpes virus infections in humans. It was also found to be effective against poxviruses, rhabdoviruses, hepadnaviruses, and some RNA tumor viruses. As other antiviral drugs have been developed, Vidarabine has become less popular but it is still used as a prescription ointment to treat acute keratoconjunctivitis, recurrent superficial keratitis, and herpes zoster.

Ecteinascidia turbinata Smithsonsian Tropical Research Institute

4. Trabectedin was one of the first anti-cancer molecules from a marine organism. The drug was approved by the EU in 2007 for the treatment of soft-tissue sarcoma and certain cases of ovarian cancer and by the FDA in 2015. The compound was first extracted from the seas squirt Ecteinascidia turbinata in 1969 and was quickly discovered to have anticancer activity. properties. However, it was not until 1984 that scientists were able to successfully isolate and characterize the key active molecules. It then took another decade to devise a reliable way to mass-produce Trabectedin. Today the compound is marketed under the trade name Yondelis for the treatment of Liposarcoma and Leiomyosarcoma and is currently in clinical trials for prostate, breast, and pediatric cancers.

Through bioprospecting and research, scientists have discovered novel medicines that have saved and improved thousands of lives. Bio-prospected compounds have also led to advancements in agriculture, bioremediation, cosmetics, and nanotechnologies. However, bioprospecting can also be harmful. When natural resources are over-harvested or when delicate ecosystems are carelessly explored it can result in irrevocable damage as well as the loss of biodiversity and future discoveries. More importantly, bioprospecting can cross the line into biopiracy – the exploitation of biological resources of other nations and/or the capitalization of indigenous knowledge without proper attribution and compensation. Like many areas of biotechnology new compound discoveries are filled with both promise and responsibility. 

Interested in incorporating bioprospecting into your biotech classroom? Check out these two online lesson plans from Kenan Fellows and Carleton College. Or assign an article about the Marine Bioprospecting as summer reading. Two suggestions are “Exploring the ocean for new drug developments: Marine pharmacology” by Harshad Malve and “Medicines from the Sea” by Kevin Krajick.