Issue Date: June 7, 2004
HOME FIELD ADVANTAGE
Although the islands of the Caribbean account for less than 0.03% of the world's land mass, more than 2% of the world's total number of plant and vertebrate species are endemic there. Given the region's rich diversity of flora and fauna, it seems only natural that its chemists would mine these riches for structurally interesting and potentially useful chemicals.
And indeed, natural products research has deep roots here: The first chemistry faculty member at the University of the West Indies (UWI)--a New Zealander named Cedric Hassall, brought in to chair the department of chemistry at UWI's predecessor, the University College of the West Indies in Mona, Jamaica--devoted himself to exploring the molecular components of the fruits, vegetables, and plants grown in Jamaica. He traced the cause of a peculiar and severe vomiting disease affecting Jamaican children to consumption of hypoglycin A, a toxin in unripe ackee, the island's national fruit.
But Hassall and his successor, British-born natural products chemist Leonard J. Haynes, did more than just inspire a locally relevant and fruitful research focus: They trained a cohort of West Indian natural products chemists, including Guyana's Wilfred R. Chan and Trinidad's Baldwin S. Mootoo, who continued the tradition of natural products chemistry at UWI. Today, the next generation of West Indian natural products chemists continues scouring the region's flora and fauna for structurally novel compounds. And increasingly, these chemists are also looking for potential applications for what they find.
With all that biodiversity, where does a natural products chemist begin? "I tend to focus on abundant Jamaican plants, particularly those West Indians commonly use for medicinal purposes," says Jamaican natural products chemist Paul B. Reese of UWI Mona. From one such plant--Eryngium foetidum, known locally as spirit weed--he's isolated a compound that inhibits a widespread and, in some cases, deadly intestinal parasite that affects both humans and cattle. The work was done in collaboration with UWI Mona biology graduate student M. Wayne Forbes and parasitologist Ralph D. Robinson. The university was recently awarded both U.S. and Jamaican patents on the compound, which has been nicknamed eryngial. A U.S. pharmaceutical company has already expressed interest in it.
Reese's colleague and fellow Jamaican, Helen M. Jacobs, targets a subset of the island's 900-some endemic plants. These have yielded, among other things, a class of structurally novel adamantane-like natural products. Jamaican natural products chemist Roy B. Porter of UWI Mona prefers to look to essential oils from Caribbean plants for potentially interesting molecules. He's now searching for aromatic compounds from an endemic tree called Bursera in hopes of finding one with antibacterial or insecticidal activity. UWI St. Augustine natural products chemist Anderson R. Maxwell has turned up a variety of novel structures from plants that grow wild in Trinidad. Recently, he and his colleagues found that members of one class, the tectoridins, can modulate calcium channel opening.
At UWI Cave Hill, in Barbados, natural products chemist Winston F. Tinto, a Trinidadian, prefers the sea. Tinto is extracting bioactive compounds from octocorals and sponges and hopes soon to expand his efforts to certain seaweeds.
UWI's natural products chemists "have historically focused on finding unique chemical structures," Tinto says. "But increasingly, UWI chemists are screening the compounds for antibacterial, insecticidal, and other activities," he adds.
In some cases, UWI chemists are also making simple chemical or enzymatic modifications to a natural product to learn how its structure affects its activity. Some UWI chemists are even attempting total synthesis of natural products. Although procuring chemicals can take weeks or even months, UWI Mona organic chemist Yvette A. Jackson has managed to work out synthetic routes to complex natural products--including a variety of rotenoids as well as some marine alkaloids--from simple, single-ring starting materials. Tinto is trying to synthesize some peptide natural products and peptide mimetics.
"We have been blessed with a great richness here in the West Indies," Maxwell says. "It's just waiting for our chemists to tap it."
- Chemical & Engineering News
- ISSN 0009-2347
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