American Mayapple Yields
By Hank Becker
July 17, 2000
WASHINGTON, July 17, 2000--A
common weed called mayapple may offer an alternative to an Asian plant that's
been harvested almost to extinction for an anti-cancer extract,
Agricultural Research Service
administrator Floyd Horn announced today.
"Besides providing a dependable, long-term supply of the anti-cancer
drug, the new extraction method--if adopted--could turn the American mayapple
into a new alternative crop for U.S. growers," Horn said. ARS and
University of Mississippi scientists
developed the new extraction method.
The near-extinct Asian plant, Podophyllyum emodi, is a cousin of the
mayapple weed found in the United States. The Asian plant makes a compound
called podophyllotoxin, used in manufacturing the cancer drug etoposide, the
active ingredient in a drug used for treating lung and testicular cancer. In
chemotherapy, the drug has been shown to inhibit the activity of an enzyme
essential for the replication of cancer cells, preventing their spread.
But shrinking supplies of the P. emodi plant in India have resulted
in export restrictions. Since synthesis of etoposide from simple building
blocks requires a costly multi step process, many attempts have been made to
develop alternative natural sources of this compound.
Working with University of Mississippi researchers, plant physiologists
Camilo Canel and Frank Dayan with the ARS
Products Utilization Research Unit at Oxford, Miss., discovered and
developed the new method of extracting podophyllotoxin. With it, they've shown
that leaves of the mayapple, P. peltatum, can yield a readily available,
plentiful and renewable source of stored podophyllotoxins.
Given the acute toxicity of podophyllotoxin, the scientists think that both
species produce the compound as a form of protection from insects and other
The ARS-Mississippi team found an efficient way to extract the compound,
which the mayapple stores in the form of glucosides. The plant adds a glucose
molecule to podophyllotoxins so the compound can be safely stored until the
plant is attacked. The key to their extraction is removing podophyllotoxin's
The new extraction method is fast, efficient and inexpensive. The use of
mayapple leaves constitutes a sustainable procedure for providing a dependable,
long- term supply of podophyllotoxin.
The team has filled a joint patent on the new technology. Talks are in
progress with pharmaceutical firms to license it to make this drug more
available in the marketplace.
For more details, see the July issue of Agricultural Research.
ARS is the chief research agency of the U.S.
Department of Agriculture.
Scientific contact: Camilo Canel, ARS Natural Products Utilization
Research Unit, Oxford, Miss.; phone (662) 915-7965, fax (662) 915-1035,