WEST LAFAYETTE, Ind. -- What do you get when you buy a bottle of the herbal cold remedy echinacea?
You really don't know what you're getting, says James Simon, professor of horticulture and co-director of Purdue's New Crops Center, because of the lack of consistency in herbs and medicinal plants.
Echinacea, for example, is used by many people to combat cold symptoms. But according to Simon, there are two different echinacea plants -- Echinacea purpuea and Echinacea angustifolia -- and most product labels give little information about which plant was used in the herbal remedy.
"Both plants produce the compound that has the biological activity, but in different amounts," he says. "Regardless of which species is used in a product, it's the responsibility of the manufacturers to come up with a mix that gives consumers the amount of the active ingredient that they need. But the amount of the active ingredient that is in the product isn't put on the label."
Echinacea is just one of many examples of the uncertainty that exists with herbal remedies and functional foods, Simon says.
"There can be differences in the biological actions of medicinal plants, depending on environmental and genetic differences," he says. "The way that a plant is harvested, and when it is harvested, can make a difference in the quality. It requires a good understanding of the plants and the environment to assess that it is high quality."
The natural variation of plants within a species can have a tremendous effect on the quality of the herbal remedy. "Some wild plants may have very high amounts, and some plants may be devoid of it. Anytime you have a natural product, there is going to be a lot of biological diversity," Simon says.
The way to control the variations in quality and to instill consumer confidence is to demystify herbal products through scientific research, he says.