Plant Medicine: Herbal Extraction Methods

Varied methods for producing herbal salves and herbal tinctures
September/October 1998
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.

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.