How DNA barcoding can boost quality control for medical plant products
By Andrea Gibson
In Pakistan, about 70 percent of people use herbal medicines because they don't have the money for or access to pharmaceutical drugs. More than 350 companies produce inexpensive, effective natural treatments for these consumers, and there are 60,000 registered traditional healers who prescribe such medicines.
But is the plant advertised on the product bottle always what's inside? To boost quality control, herbal medicine companies in Pakistan reached out to university scientists.
An Ohio University alumnus connected Professor Zabta Shinwari of Pakistan's Quaid-i-Azam University with Professor Allan Showalter, an expert on plant molecular biology in the Department of Environmental and Plant Biology and the Molecular and Cellular Biology Program. With funding from the Pakistan government and the U.S. National Academy of Sciences, the researchers have worked over the last three years to sequence specific segments of DNA for 43 plants commonly used in herbal medicines and to create a database of their findings.
The concept, known as DNA barcoding, is used by scientists around the globe to catalog genetic material from thousands of different living things, including various bacteria, fungi, plants, and animals, Showalter explains. Similar to the unique pattern of bars in a universal product code that identifies each consumer product, a DNA barcode is a unique pattern of DNA sequence that identifies each species of life on the planet.
Showalter and Shinwari hope that their database will be used by the Pakistan companies, which are now required by law to verify the contents of their products.
"With barcoding, you also eliminate the need for continual native plant expertise," Showalter says. "If you have a DNA sequence, you don't need to see the plant and have the taxonomist identify it."
Although the database is designed for quality control in the laboratory, Showalter notes that scientists hope that a handheld device also could be developed to verify the identity of plants right in the field.
The database could be useful beyond the borders of Pakistan. There are other countries around the globe where 50 to 80 percent of the population relies on herbal medicines, Shinwari says. And even in nations—including the United States—where people may have good access to pharmaceutical drugs, some choose natural treatments for religious or other personal reasons, Showalter adds.
The project not only could help improve product safety for the industry and its consumers, Shinwari says, but could have economic impacts as well. Most of the herbs used by companies are harvested from the wild by women and children. As this activity can make up about 20 percent of their total annual household income, he says, the new database could support the jobs of many rural people below the poverty line.
This story will appear in the Spring/Summer 2014 issue of Ohio University's Perspectives magazine, which covers research, scholarship and creative activity.
Illustration: Christina Ullman