New light on medicinal benefits of plants

The release of the resources follows a $6 million initiative to study how plant genes contribute to producing various chemical compounds, some of which are medicinally important.

"Our major goal has been to capture the genetic blueprints of medicinal plants for the advancement of drug discovery and development," said Joe Chappell, professor of plant biochemistry in the University of Kentucky College of Agriculture and coordinator for the Medicinal Plant Consortium (MPC).

Project partner Dr Sarah O'Connor at the John Innes Centre will now work with her research group towards the first full genetic sequence of a medicinal plant and will also experiment with combining beneficial properties from different plants to create the first new-to-nature compounds derived from plants. A priority focus will be compounds with anticancer activity.

"Fewer and fewer new drugs have been successfully making it to the marketplace over the last 10 years, in large part because of a reliance on chemical synthesis for making new chemicals," said Chappell. "Somehow in our fast-track lives, we forgot to take advantage of the lessons provided by Mother Nature. That is all changing now with the recognition that two-thirds of all currently prescribed drugs can be traced back to natural sources and the development of resources such as those in the MPC to facilitate new drug discovery activities."

Some well-known medicines have come from plants. The once ubiquitous foxglove gives us the cardiac muscle stimulant digoxin. The periwinkle plant offers a source for the widely used chemotherapy drugs vincristine and vinblastine. These and many other medicinal plants, often commonly found in household gardens and flower boxes, harbour a wealth of compounds ripe for medicinal applications.

"Just as the sensory properties of plants interact with and trigger your sense of smell, plants' natural compounds can target and cause a reaction within your body. This gives them tremendous pharmaceutical potential," said Chappell.

During this two-year project researchers set out to develop a collection of data that would aid in understanding how plants make chemicals, a process called biosynthesis. This knowledge ultimately could make it possible to engineer plants to produce larger quantities of medicinally useful compounds as well as different versions with other therapeutic potential.

To develop the resources, the researchers studied the genes and chemical profiles of 14 plants known for medicinal properties or compounds with biological activity. These included plants such as foxglove, ginseng, and periwinkle. The findings will help researchers discover how nature's chemical diversity is created and enable them to uncover new drug candidates or increase the efficacy of existing ones.

"The current understanding of molecules and genes involved in the formation of beneficial compounds is very incomplete," said O'Connor, who is also a lecturer in chemical sciences at University of East Anglia. "However, the ability to conduct genome-wide studies of model plant species has resulted in an explosive increase in our knowledge of and capacity to understand how genes control biological processes and chemical composition."

The MPC project includes participants from the University of Kentucky, Michigan State University, Iowa State University, the University of Mississippi, Purdue University, Texas A&M University, Massachusetts Institute of Technology, and the John Innes Centre in Norwich. The researchers represent a broad spectrum of expertise from plant biology and systematics to analytical chemistry, genetics and molecular biology, and drug development from natural products.