WICHITA,
Kan. — For decades the native prairie plant with tomato-like vines,
and marbled-sized fruit covered in thin husks, has sprawled across the Kansas
prairie in relative obscurity.
But scientists
from around the world are now noticing the wild tomatillo, and wondering if it
might provide a major medicinal breakthrough.
"We've
found compounds from the wild tomatillo that have strong anti-cancer properties
against breast cancer, skin cancer, thyroid cancer and brain cancer in our
early studies," said Mark Cohen, cancer physician and research scientist
who has been working with the plant for more than two years.
"It's very
exciting because not only do those compounds occur naturally, but they're more
potent than some drugs currently on the market for these diseases."
Cohen said
initial research has been done against human cancer cells in laboratory
containers and mice. Things are progressing well enough that human-based trials
could begin in about two years, he said.
It seems the
deeper the botanists, medicinal chemists and cancer researchers dig into wild
tomatillos, the more promise the prairie plant holds.
"We've
found 15 new molecules in the plant previously not known to science," said
Barbara Timmermann, University of Kansas medicinal chemistry chair.
"Nobody knew they existed and several of them are so active against
cancer."
And it's not
like this is some super-delicate plant from some far away corner of the Amazon.
Wild tomatillos, Physalis
longifolia, are a tough, prolific prairie plant currently thriving over much of
the central United States. (They're related to a domestic variety of
tomatillo, but scientists don't know if it has similar characteristics.)
But promised
funding was abruptly cut less than halfway through the five-year research
project.
"We are
having fantastic data, and things are moving so well, then they just pulled the
rug out from under us," Timmermann said, of money from Heartland Plant
Innovations. "It's very unfortunate, and very disappointing."
The Native
Medicinal Plant Research Program began in 2010 as a joint venture using the
strengths of the Kansas Biological Survey, the KU School of Pharmacy and the KU
School of Medicine.
Timmermann and
Kelly Kindscher, a biological survey senior scientist, have long seen the
Kansas prairies as a potential pharmacy waiting to be explored.
"Everybody
has been going to the rain forest and other exotic places for research,"
said Timmermann, who has about 30 years of experience researching medicinal
plants, "but we knew the Midwest had so many plants nobody had ever really
looked at."
Kindscher, a
noted expert on America's prairies, had also learned that for centuries native
tribes were utilizing a number of plants for medicinal purposes before the
state was settled.
"They
weren't collecting them randomly," Kindscher said. "They'd learned
what to use, and used them in many cases fairly effectively."
He said modern
research has shown most do indeed work.
Kindscher said
any medicinal benefits found in plant compounds are mostly coincidental. Most
are produced to protect the plant in some way or another.
"Plants
can't run and they can't just grow spines if they don't have them, so they need
some kind of chemical defense against being eaten by insects or
something," he said.
They also may
help them survive tough conditions, like floods and drought. While
Kindscher and crew eventually provided about 200 different species of prairie
plants for testing, wild tomatillos quickly gained the most attention because
of the findings in Timmermann's lab.
As well as
testing how the wild tomatillo compounds perform against cancer, the plants
were also tested to see how they react to other kinds of human cells.
It would be
possible, Cohen said, for a compound to be very aggressive against cancer but
too toxic to healthy human cells to become a viable treatment.
Fortunately,
that hasn't been the case so far.
"It's very
exciting that (wild tomatillo compounds) do have a strong potency effect
against cancer and do not have significant toxicity against other cells so far
in our evaluations," said Cohen, who is directing laboratory testing on
the wild tomatillo compounds furnished by Timmermann.
Initially Cohen
did so at the KU School of Medicine. He took the chores with him to a new job
at the University of Michigan.
If all goes very
well, Cohen said clinical trials with humans could begin within about two
years. Wild tomatillo-based drugs could possibly hit the general market within
about seven years.
It's too early
to know how the medicine could be administered, if it passes all testing and
trials.
Cohen said it
could probably be injected into patients.
An oral wild
tomatillo extract could be another option.
Kindscher said
some of the highest levels of cancer-fighting compounds are found in the
plant's fruit.
"The fruit
is edible, and actually tastes very good," he said, "especially when
it's ripe."
Acquiring enough
of that fruit shouldn't be a problem in the future.
Wild tomatillos
are so common Kindscher referred to them as "a common field weed"
that grows on native prairies, pastures and farmlands, roughly from New Mexico
to Montana and as far east as Ohio.
"It's
probably one of the few (prairie) plants that are doing about as well as
ever," he said. "It's common because it can grow in a lot of areas.
Unlike a lot of prairie plants it does well on disturbed soils."
He said it grows
well along roadsides or where the soil has been scarred by livestock.
It's common in
farm fields, too. Kindscher is certain it could be grown commercially, too.
The perennial
plant has proven to be hardy to temperature and rainfall extremes.
But one thing
this miracle plant cannot do, is pay for its own research. All three scientists
said funding is now their greatest worry.
Timmermann said
Heartland Plant Innovations originally agreed to pay $5 million over five years
to fund the research.
Heartland is a
Manhattan-based bio-technology company backing plant-based research. In the
spring, nearing the end of the program's second year, Timmermann was told
funding would stop immediately.
"This just
comes at a very bad time," she said. "This is when we should be
growing." Currently the program is running on funding she'd saved from the
previous two years.
Forrest Chumley,
Heartland Plant Innovations' president, said the decision to stop the funding
at about $2.5 million was a business decision.
"We're a
for-profit company so we focus on projects where we can make the greatest
difference. We've decided it's time to really focus on wheat development,"
he said. "We're really proud of what (the Native Medicinal Plant Research
Program) has accomplished, and think it has great potential."
Chumley said
budget cuts to the state-financed Kansas Bioscience Authority, one of his main
sponsors, also left his group with less money.
Researchers are
now searching for further funding. "It's very exciting that this may
represent some new cancer drugs," Cohen said. "Unfortunately our
biggest challenge is now acquiring more funding so we can move things to the
next level."
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