Botanical products are vulnerable to unintentional adulteration linked to processing solvents and international differences in plant names, experts say.

While intentional or economically motivated spiking of supplements garners more frequent attention, unintentional adulteration also can cause regulatory problems for manufacturers, according to presenters at a U.S. Pharmacopeia workshop on adulteration of food ingredients and dietary supplements.

Solvents used to prepare extracts often are overlooked as contributors to adulterated botanicals, natural products consultant John Cardellina said at the Nov. 16 event in Rockville, Md.

Many ingredient manufacturers, seeking greater control of the extraction process, use substances other than the traditional water or aqueous ethanol as solvents.

The resulting extracts may contain residual amounts of the solvents, some toxic at certain levels, said Cardellina, who consults with the National Institutes of Health’s Office of Dietary Supplements.

FDA accounts for the residual solvent issue in its new dietary ingredient notification draft guidance, which regards a dietary ingredient as chemically altered if made with a solvent other than water or aqueous ethanol Also see "NDI Guidance Sparks Questions Even From Firms Ready To Comply" - Pink Sheet, 18 July, 2011..

Solvents Missed In CofAs

Further, manufacturers frequently lack visibility into which solvents their suppliers use, since certificates of analysis usually omit this information.

“There’s clearly a need for more education in this area,” Cardellina said.

“I think a lot of people don’t realize that most of the materials they buy – as raw material supplies or extracts – have certificates of analysis with them but very few mention solvents or solvent residues,” he added.

The American Botanical Council is working on a white paper – intended as a “go-to reference” for industry, Cardellina said – that will cover acceptable limits for 22 solvents, including carbon dioxide, glycerin and vinegar. Publication is expected in spring 2012.

“I think a lot of people don’t realize that most of the materials they buy – as raw material supplies or extracts – have certificates of analysis with them but very few mention solvents or solvent residues.” – botanicals consultant John Cardellina

ABC, in conjunction with the American Herbal Pharmacopoeia and industry groups, is rolling out a botanical adulterants program to produce educational materials addressing both accidental and intentional adulteration ([A##05111107011]).

A Botanical By Any Other Name

Every plant species has a specific scientific name, but discrepancies in common names used in the vernacular of commerce can result in unintentional adulteration, explained botanical taxonomic researcher Wendy Applequist.

Nomenclatural confusion is especially prevalent in international trade, said Applequist, an associate curator at the Missouri Botanical Garden’s William L. Brown Center in St. Louis.

For example, in China botanical firms traditionally use plants interchangeably when they are considered to have similar attributes, she said.

“Whether that’s fraud or well-meant substitution is not quite clear,” Applequist said.

Such cultural differences may play a role in ingredient suppliers selling Siberian ginseng as comparable to American or Asian ginseng, which it is not.

Even in North America, botanical taxonomies can get scrambled along the supply chain, Applequist said.

She alluded to arnica montana, a European species used in the U.S. as a topical anti-inflammatory. A similar plant abundant in Mexico is simply “arnica,” but commonly referred to in the U.S. as “false arnica.”

“The Mexican collector, when he sells you a bag of arnica, he’s not lying. That is arnica in his opinion,” Applequist said.

“Selling things across borders has the potential to create real confusion regarding what these names are supposed to mean,” she added.

The best solution to divergent taxonomies would be strict labeling of all botanical ingredients by their scientific names from the beginning of the supply chain, Applequist said.

She acknowledged that this likely would, in turn, confuse collectors of wild materials accustomed to calling plants by their local names.

Solvents, Taxonomy Confusion Can Lead To Unintentional Botanical Adulteration

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