There is no better source of healing substances than mother nature herself. And it seems that our seas have “oceans” of compounds waiting to be discovered. Since the 1960s, scientists have been exploring the ocean for marine products that may be beneficial to human health. However, natural products are considered time-consuming and too expensive to develop so that pharmaceutical companies lost interest before researchers can discover the useful compounds. Hence, only 14 natural products which originated from the marine environment are currently undergoing clinical trials.
One of the most promising compounds so far is marine extract called largazole, which has been shown to have potent anticancer properties. Largazole was extracted from cyanobacteria (blue-green algae) that grow on the coral reefs off the coast of Key Largo, Florida. This compound was discovered by University of Florida College of Pharmacy researchers headed by Dr. Hendrik Leusch. They found that largazole acts on a group of enzymes called histone deacetylase or HDAC. Over-active HDACs are found to be associated with cancers like prostate and colon tumors. When HDACs are inhibited, the genes that suppress tumors are activated. In addition to its HDAC inhibitory properties, largazole exhibits potent antiproliferative activity and these two seems to be correlated.
“It’s exciting because we’ve found a compound in nature that may one day surpass a currently marketed drug or could become the structural template for rationally designed drugs with improved selectivity,” according to Luesch.
Leusch and his research team have been working on cyanobacteria since 2006. The cyanobacteria were provided by collaborator Dr. Valerie Paul at the Smithsonian Marine Station in Fort Pierce. Last year, the team discovered one potent extract that has toxic activity to cancer cells – largazole. The compound’s chemical structure was first reported in Journal of the American Chemical Society in February this year. The laboratory synthesis and the molecular mechanism of its mode of action were described in another report in July in the same journal. This compound is now patented to University of Florida. Leusch and his team are now collaborating with Jiyong Hong at Duke University to reproduce largazole in its natural structure and actions in the laboratory.
Leusch is also working on other anti-tumor natural products from Atlantic and Pacific cyanobacteria. “We have only scratched the surface of the chemical diversity in the ocean,” Luesch said. “The opportunities for marine drug discovery are spectacular.”
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