August/September 1999 THIS ISSUE: Education Mathematics Pharmacy Ethics Briefs INDEX: |
Plant Detective by Caroline Lupfer Kurtz
Fully one-fourth of all common medicines are derived from plants, Medora says, although less than 2 percent of the rainforest has been thoroughly examined for potential human benefits. Medora has been to Peru, Belize and Brazil on several occasions to bring back specimens to be screened for possible drug uses, having first secured agreements with indigenous groups to safeguard their intellectual property rights. He recently returned from his native India, where he negotiated an agreement with the Foundation for the Revitalization of Local Health Traditions for the same purpose. “Plants can contain tens, hundreds, even thousands of chemical compounds that act on biological systems in various ways,” Medora says. “It can be very time-consuming testing each extract for activity and then finding out what specific component or components are causing the pharmacological effects.” Seeking clues afield He also shares his knowledge with a wider audience through Elderhostel seminars and in “The Plant Detective: A Phytomedicinal Whodunit,” a popular weekly Montana Public Radio program that introduces listeners to the value and history of drugs derived from plants — both common and rare. Medora has become a bit of a rare breed himself. Since the 1950s and the rise of research on synthetic drugs, universities and pharmaceutical companies have invested less and less time and money on the medicinal properties of natural products. These days the pendulum appears to be swinging back because of heightened interest in and public awareness of natural medicines, Medora says. Schools are starting to offer courses in the subject again but lack trained specialists to teach it, which makes him a valuable resource.
In October, Medora will take a group of Montana students, faculty members, physicians and pharmacists to Peru where they will participate in a weeklong seminar, Pharmacy from the Rainforest, sponsored by UM, the American Botanical Council, the Texas Pharmacy Association and International Expeditions Inc. “The trip will expose students and others to a different form of medical treatment as practiced in another country,” Medora says. And, hopefully, foster further research in this area. And at home According to Medora, headache medicine works by either stimulating or inhibiting serotonin receptors in the nervous system. With the help of undergraduate and graduate students, the researchers grow cells in culture, then expose pieces of cells with their associated serotonin receptors to existing drugs — either natural or synthetic — that are known to bind with the receptors. These drugs are tagged with a radioactive isotope so that their reactions can be followed in a test tube. The students then add various concentrations of extracts from different natural sources — in particular, the common weed St. John’s wort — to see if anything in the extract replaces the tagged drug on the receptor. “If something in the extract is similar in action to the known drug, it will compete with it for the binding sites,” Parker says. “We are measuring the capacity of the unknown drugs to compete with the labeled ones.” Parker and Medora are collaborating on the St. John’s wort research with Nutritional Labs International, a 2-year-old contract manufacturer of dietary supplements in Lolo. The plants themselves are grown at Montana State University extension stations. So far, their crude extracts have shown high levels of activity in the binding tests, as much or more than any other natural product tested in their lab. Once the researchers determine that an extract of St. John’s wort has an effect, they send the sample to Nutritional Labs for finer separation into specific compounds or groups of compounds for further testing. “It’s literally like looking for a needle in a haystack,” Medora says. “Quite often more than one substance may be working in conjunction, which makes it even more complicated to sort out.” In their work with St. John’s wort and feverfew, a type of daisy, the researchers have discovered that known active ingredients hypericin and parthenolide, respectively, are not the entire story. Further elucidation, however, will depend on further funding. “This type of research is very time-consuming work,” says Parker, “very labor intensive and relatively expensive.” The hunt continues In addition to Nutritional Labs’ basic quality and safety testing and manufacturing operations, President and CEO Terry Benishek sees a need for more research on herbal medicines in general. “We want to help increase knowledge of the therapeutic effects [of herbs] and establish more realistic quality specifications,” he says. Medora and Parker are hopeful about the prospect of a small business grant since the field of natural medicines offers great potential for discovery. In addition, “the expectations of the public have led to lots of confusion over the efficacy of herbal remedies,” Parker says. “Active ingredients [in plants] vary greatly from batch to batch and differ among the same kinds of plants grown in different places. There is a real deficiency of research in natural products in the United States. We are way behind Europe and Asia in this.” Which leaves plenty of work for a couple of plant detectives. |
