For thousands of years, mankind has been using natural substances for medical purposes. Common drugs such as aspirin, quinine, taxol, penicillin, and morphine originally came from tree barks, molds, and flowers. Folk medicine's long learning curve has been with us as long as man has trod the earth. Scientists continue to research medical practices of primitive peoples, searching for "witch doctor" medications that can be adapted to the modern world. The number of drugs being derived from sources on land continues to decrease, however. Most of the major finds have been made, yet the number of diseases that have developed resistance to previously effective pharmaceuticals has increased.
The World Ocean represents mankind's new drugstore. The single largest geographic feature on our planet, less than 5% of it has been explored. It is here, however, that most of the living things on our planet reside. It is reasonable to expect that bioactive marine compounds of great diversity and utility will be found here. Estimates are that more than 10% all of marine organisms have compounds that could be medically important. It is interesting to note that bioactive substances on land come primarily from plants, but in the ocean the opposite is true. Experts say the chances of finding a bioactive substance are 500 times higher with marine organisms than with land dwelling flora and fauna.
Compared to the history of medicine on land, the search for bioactive marine substances is relatively new. Serious work in this area began in the late 1960s. It is a daunting task, considering the millions of living marine species to be assessed. Add to this the fact that probably only a fraction of the seas' flora and fauna have been discovered. Nevertheless, over the past four decades some 100,000 marine organisms have been systematically evaluated for potential drug use. There have been some remarkable results, and a few have been approved for human use.
Recent research has found cancer-inhibiting bioactive substances in microbes that live in bottom sediments on the deep seafloor. Presently, marine invertebrates such as shrimps, worms, corals, tunicates, and sponges are the best sources of active compounds. This is because of their relative inability to move quickly, if at all, to escape predators. Instead of fleeing, they resort to "chemical warfare" as a defense mechanism. By exuding bad tasting or toxic substances they are able to survive in very hostile environments.
The assessment process begins with collecting quantities of the organism and then extracting the active compounds. The material is then examined for clinically relevant properties such as antiviral, antitumor, antifungal, or anti-inflammatory activities. Once an activity has been detected, the next step is to decode its chemical makeup as the first stage in synthesizing the substance. Some marine-derived compounds are so complex, however, that present analytical methods are unable to do this.
The supply of sufficient natural material is a major problem. Literally tons of an organism might be required to extract a few ounces of an active compound for research work. Clearly this would not be practical when commercial-scale quantities are required. This dilemma is a good example of the considerable distance sometimes found between laboratory success and moving a drug to the marketplace. A more practical alternative is to grow the organism in a mariculture (fish farming)-type facility where large quantities can be produced under controlled conditions.
It takes many years and tens of millions of dollars to bring a new drug to market. Once bioactive compounds from a plant or animal are isolated and tested in the laboratory actual trials begin, first on animals and later with human subjects. On average, only one out of 250,000 compounds tested eventually becomes an approved drug for human use. The first research on marine compounds began nearly 40 years ago, but it is only now that the first drugs from the sea are beginning to come on the market. This is not a business enterprise for the impatient or those with less than deep pockets.
Today, there are several compounds in their final stages of clinical trials. Nearly 300 patents for them were awarded between 1969 and 1999. After many years of research and trials, many of them will be moving into the marketplace soon. Among the pharmaceuticals ready to launch are those for treatment of certain types of cancers and leukemia, mitigation of pain with no risk of becoming drug dependent, reduction of inflammation and swelling, promotion of bone growth, and mitigation of bone loss in people suffering from osteoarthritis.
So if someday your doctor orders, "Take two clams and call me in the morning," do it.