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Plant Medicine: Herbal Extraction Methods

Author Photo
By N/A

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Kristen Myers, lab manager for Turtle ­Island Herbs in Boulder, Colorado, pours an oil solvent, called a men­struum, onto fresh arnica. The oil and herb will be mixed, then left to soak.
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Finished extracts sit in dark bottles in Turtle Island’s Boulder laboratory.
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Herbs and solvent are blended in a huge vat at Nature’s ­Apothecary.
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A chemical analyst at Hauser, Inc., takes a ­computer reading to check the medicinal content of an herbal extract.

In the foothills of the Rocky Mountains, three
herbal product manufacturers are hard at work drawing medicinal
compounds from plants. Two of these companies are less than a mile
apart in Boulder, Colorado, and a third is in nearby Louisville.
But the roots of their methods and philosophies are very
different.

Each manufacturer has its own method of extracting plant
medicine, which is then used to make salves and tinctures that are
sold nationwide. While the method may not make a difference to
consumers, it should, each manufacturer says–with all due respect
for the others.

Different extraction methods illustrate the contrasting
philosophies pulling at the ends of contemporary herbal medicine.
One supports the highly scientific method of standardization, which
involves measuring and extracting specific compounds believed to be
responsible for the herbs’ medicinal effects. The other is the
traditional “whole herb” school of thought, which asserts that all
of a plant’s compounds contribute to its ability to heal and
protect health, and plucking out one or a few compounds means
losing that synergy.

“Just because something is standardized or has scientific
testing behind it does not mean that it is high standard–scientific
validation is no guarantee of quality,” says Feather Jones, founder
of Turtle Island Herbs in Boulder and director of the Rocky
Mountain Center for Botanical Studies. “Plants are like people. You
can’t standardize them.”

Rod Lenoble, scientific affairs manager at Hauser, Inc., has
another view. “We’re generally conservative,” Lenoble says. “But
we’re looking at the totality of scientific data and preparing
extracts using ­ratios that were proven to be effective in the
studies.”

Hauser supplies companies such as Rexall with herbal extracts.
Hauser’s extraction process is a trade secret, but Lenoble says it
“emulates a tea cup”–plant material is put into a big vat with a
solvent of ethanol and water, known as a menstruum, to draw out the
plant’s constituents; Lenoble says their low-heat process combined
with the watered-down ethanol makes for a gentler solvent. The
process also entails computers, analytical chemistry, and
pharmaceutical testing, all required to ensure that the final
extract contains specific compounds in set ratios.

Down the road from Hauser at Turtle Island, which sells its
brand directly to retailers, the process is more traditional and
less scientific, in the mainstream sense of the word. Under Jones’s
direction, employees extract to “maximum potency” standards laid
out in The United States Pharmacopeia (USP). The USP contains
official herbal monographs first written in the 1800s and updated
through the 1920s, when the U.S. medical community turned away from
herbal remedies to focus on synthetic pharmaceuticals.

On receiving a shipment of fresh herbs (or dried and powdered,
in the case of such herbs as Siberian ginseng), employees add the
material to measured amounts of oil, alcohol, or other solvents. In
the case of the arnica, which Turtle Island received early last
summer from a Montana supplier, the whole plant–stems, leaves, and
flowers–is mixed with solvent, then left to “soak,” or macerate, in
the dark for about two weeks.

Turtle Island also is known for using the percolation method of
extraction–a labor-intensive way to glean an herb’s constituents,
but, Jones says, one of the surest ways to obtain a superior
extract, even in taste. The method differs from other extraction
processes because the herb doesn’t sit in its own liquid. Dried,
powdered herb is put into a large vial with a drip valve on the
bottom. A paper filter is set on top of the herb and a measured
amount of solvent poured onto the filter. Over the course of
twenty-four hours, the solvent works its way through the powder,
dripping out at the slow speed of one drip per second, much like
freshly ground coffee in an old-fashioned percolator.

Unlike Hauser, Turtle Island doesn’t put its herbal preparations
through high-tech testing. Jones chooses not to do it. “We know
what these herbs can do based on many, many years of use,” she
says. “Scientific testing isn’t the bottom line of validity.”

Proponents of standardization say it’s the solution to
the natural variability found in raw herbs.

Distilling the language

Extraction refers to the process of obtaining
an herb’s medicinal constituents by using an appropriate solvent,
such as grain alcohol or glycerine, to get them out of the plant.
Extraction is an age-old process and easy to do yourself–it can be
as simple as making an infusion. Most of us, though, will trust
someone else to do it for us. If you’re curious about the extraction methods your supplier
uses, check the product label or ask for product literature. This
should help you make informed decisions when you’re ready to buy an
herbal supplement.

Here’s a description of the extraction methods commonly used in
herbal medicine:

Infusion: The simplest extraction method; it’s
similar to making a tea, but more precisely defined. Infusions are
most appropriate when extracting constituents from leaves, flowers
and green stems. General guidelines suggest one part dried herb or
three ounces fresh herb to twenty parts water steeped five to ten
minutes.

Decoction: Similar to an infusion but used when
the plant material is hard and woody, such as roots, rhizomes,
seeds, or bark. Simmer one part herb to twenty parts water for
fifteen to twenty minutes.

Maceration: The most common or popular way to
tincture an herb, this process usually calls for ethanol, or grain
alcohol, which is a better solvent than water because it extracts
most of the ingredients from the herb and also acts as a
preservative. Occasionally vegetable glycerine or vinegar is
used—vinegar behaves similarly to alcohol, and glycerine is easier
on the stomach–but neither of them dissolves plant constituents as
well as alcohol. Vinegar and glycerine are appropriate for children
or people with alcohol sensitivities. Herbs are placed into a
container and alcohol is added; a common ratio is one part herb to
five parts solvent.

Digestion: Similar to maceration, but with the
addition of gentle heat.

Expression: Forcibly separating liquid from the
plant by using a press.

Percolation: One method for extracting dried,
finely powdered herbs. The powder is placed into a vial, a paper
filter is set on top, and solvent is poured onto the filter. The
solvent works its way through the powder for twenty-four hours
(more solvent is added as needed) and drips slowly out of a valve
on the bottom of the vial–carrying the extracted medicinal
constituents with it.

Not far from Hauser and Turtle Island, employees at Nature’s
Apothecary in Louisville, Colorado, also are preparing extracts.
The rapidly growing company just moved into a large building
equipped with a chemistry lab, warehouse, and “kitchen,” where the
extracts are prepared. The kitchen is a sterile-looking place, and
Darrin Duber, Nature’s Apothecary marketing director, whispers when
he enters. The herbal extraction process can take from four to six
weeks and requires a lot of energy on the part of the plants, he
says with a smile, and they must be treated respectfully.

Nature’s Apothecary comes down somewhere in the middle of the
two philosophies of extraction, Duber says. Of the more than three
hundred products Nature’s Apothecary makes, only seven are
standardized or “fingerprinted” for content, he says. “We’re aiming
for an even balance between traditional use and science,” Duber
explains, noting that several herbalists and a chemist are on
staff. “With the traditional way [of extraction], there is no
guarantee that the medicine is there. But there is the concept
called synergy–and the synergy of all of the different constituents
affects the final product.” The differing philosophies make for interesting debate, but they
also may lead to frustration for consumers. Herbal supplements
aren’t regulated the way drugs are, and label information can vary
widely.

However, representatives at each company offered some shopping
tips:

• Choose products with straightforward labels that offer
information you can understand. For example, a product may have a
catchy name, but you may have to search for the list of ingredients
and wonder whether they all really treat your health concerns. If
you’re looking for nettles as a treatment for allergies, for
example, find a product with a simple, straightforward
name–“Nettles.”

• When a product label states that the bottle contains a
standardized herbal extract, it means that the product is
guaranteed to contain a minimum level of the major active
ingredients. Proponents of standardized herbal products say that
standardization is the solution to the natural variability found in
raw herbs, which comes with different growing conditions, such as
an abnormally wet or dry season.

• Find a brand you can trust and stick with it.

• Read about your condition and the herb or herbs you’d like to
try. Informing yourself about a particular herb or herbal medicines
will help you when you stand before the vast array of supplements
on market shelves.

Sources: Green, James. The Herbal Medicine-Maker’s Handbook.
Forestville, California: WildLife & Green, 1990. Hoffmann,
David. The Complete Illustrated Holistic Herbal. Shaftesbury,
Dorset: Element, 1996.

Published on Sep 1, 1998

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