March 5, 2010
CONTACT: K.E. Schwab
SRU's Forbes earns patent for indigenous medicine work
SLIPPERY ROCK, PA. - Sometimes there is just enough truth in folklore and home remedies on which a serious scientist can base a cure. Such is the case for Wayne Forbes, assistant professor of biology at Slippery Rock University, who has been awarded a U.S. Patent for his isolation of a compound that kills an often-fatal intestinal parasitic roundworm called "threadworm."
This parasite, formally known as Strongyloides stercoralis, is commonly found throughout the tropics.
"It was exciting work," Forbes said after learning his patent application had been granted by the U.S. Patent Office late last month. "The patent is for work done by my colleagues and me, as principal inventor, while at the University of the West Indies, Mona Campus, in Jamaica," he said.
His research colleagues were Ralph Robinson and Paul B. Reese, both of Kingston, Jamaica.
Forbes joined the SRU faculty in 2003. He earned his doctorate in zoology and bachelor of sciences degree in zoology and botany at UWI in Jamaica.
"We took plants used in folklore for treating intestinal roundworm infections in the Caribbean and other tropical regions, and identified and isolated the potent antiworm compound called eryngial (Trans-2-dodecenal) from spirit weed (Eryngium foetidum), the most effective plant of the lot," he said.
"The next step is to find a pharmaceutical company willing to take on the major research of determining the effects of the compound on human and other mammalian subjects, and taking the compound public," he said.
Forbes points out that pharmaceutical research could lead to the development of a synthetic compound that would mimic the original compound's properties. The data indicate that millions of people, mostly in tropical regions, suffer from strongyloidiasis and success of the compound could be very profitable for the pharmaceutical taking on the work.
The patent application notes: This invention relates to killing of nematodes (round worms and more particularly to treatment of infections caused by parasitic nematodes).
Forbes said people often walk around barefooted in tropical regions, thus allowing infection by threadworm upon skin contact. The infection can be long-lived, more than 30 years, and asymptomatic in otherwise healthy individuals. However, the worms rapidly multiply in sick and/or immunosuppressed/compromised persons leading to hyperinfections.
"Mostly, in chronic infections, people seem to suffer from bouts of alternating constipation and diarrhea, abdominal pain, weight loss, vomiting, unexplained headaches and dizziness. Severe cases - hyperinfections - if left untreated, can be fatal," Forbes said. Thiabendazole, the drug of choice, has unpleasant side effects, is expensive and not very effective. Additionally, the parasite could develop resistance to ivermectin, the more recently used pharmaceutical. "We hope that with our new compound, should it prove effective in treating humans, such problems that militate against effective treatment in endemic regions can be removed," he said.
Forbes' research began after hearing folklore claims that intestinal worm infections could be successfully treated with concoctions/decoctions of a variety of tropical plants. "We tested crude extracts of 25 Jamaican plants, which led to spirit weed being the most effective and the source of eryngial," he said. "Our goal is to disrupt the parasite's life cycle by targeting the infective and possibly other stages," he said.
Spirit weed is a small, herbaceous shrub, approximately 12 to 18 inches tall and plentiful in the Caribbean islands, especially in shaded areas along riverbanks.
His patent documentation reports that S. stercoralis infects more than 100 million persons worldwide. It is the most common parasitic nematode that is able to recycle and proliferate within its hosts. Chronic, usually asymptomatic, gastrointestinal infections result in the majority of otherwise healthy individuals, but in immunocompromised hosts or persons receiving immunosuppressive therapy, inordinate multiplication of the parasite is followed by dissemination of larvae and adults to virtually all organs of the body. "This is a grave and often lethal condition," he said.
To explain his specific interest in tropical plants, Forbes said there are indications that some 25,000 species of higher plants are used medicinally throughout the world, where 80 percent of the population, most living in the tropic zone, rely heavily on traditional plant-based medication for health care.
"The potential of indigenous medicines is also recognized in the developed world, although to a much smaller extent. In the U.S., for example, close to 100 secondary plant products have been incorporated as purified ingredients in more than 25 percent of prescribed preparations dispensed from the 1980s to the present time," he said.
While Forbes' research concentrated on S. stercoralis, other parasitic intestinal nematodes,
including hookworms (Acylostoma doudenale and Necator americanus), Haemonchus contortus, Ascaris lumbricoides and Trichuris trichiura, are medically significant in humans and other mammals. It is estimated that some 1.2 billion people worldwide are infected with Ascaris, while some 800 million people are infected with Trichuris.
He said he hoped further work would result in his compound being effective against other such parasitic nematodes as well.
Before joining SRU, Forbes was a postdoctoral fellow at the University of Pennsylvania, School of Veterinary Medicine, department of pathobiology. He was also a former scientific officer for the
Department of Natural Products, Scientific Research Council in Jamaica.
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