Pharmaceutical Use

About half of all the drugs currently in use are derived from natural products. These include many of the anti-infective and anti-tumour drugs developed during the past twenty years. Terrestrial plants have been the principal source but marine organisms are most rapidly expanding sector. There is nothing new is using marine products for medicinal purposes, with seahorses being used for centuries in traditional treatments for sexual disorders, respiratory and circulatory problems, kidney and liver diseases, amongst other ailments, in China, Japan and Taiwan.

More recent research has developed a cancer therapy made from algae and a painkiller derived from the toxins in cone snail venom. Anti-viral drugs Ara-A and AAZT and anti-cancer agent Ara-C were developed from a Caribbean coral reef sponge, and Dolostatin 10, extracted from an Indian Ocean sea hare is undergoing clinical trials for the treatment of breast cancer, tumours, and leukaemia.

At first organisms tended to be collected in huge quantities, more or less at random, in the vain hope that some useful compound might be extracted later. This involved the unpleasant homogenisation (blending) of tonnes of material to extract minute quantities of chemicals for testing. In one case 1600 kg of a sea hare were used to isolate just 10 mg of a compound to treat melanoma, though in explorative experiments as much as 1 kg many be need for bioassays. Genetic engineering has made prospecting for new drugs much more environmentally friendly, it being routine to collect as little as 1 kg of living material. DNA is then extracted from this and cloned into host bacterial cells which produce large quantities of the chemical in the laboratory.