ABC puts out lab document on grapefruit seed extracts

By Hank Schultz

- Last updated on GMT

iStock photo
iStock photo
The American Botanical Council has released another in its series of laboratory guidance documents, this one covering the controversial product grapefruit seed extract.

The document is issued under the auspices of the Botanical Adulterants Program, which a joint effort between ABC, the National Center for Natural Products Research (NCNPR) at the University of Mississippi and the American Herbal Pharmacopoeia (AHP). This is the 31st peer-reviewed publication of the program and the fourth in the series of lab guidances.

Grapefruit seed extract is often known as GSE.  ABC is promoting a more specific acronym—GFSE—to distinguish this product from grapeseed extracts.  It’s an important distinction, not just because we’re talking about two different plants here but also two botanicals with widely divergent backing in terms of evidence.  There is a thick sheaf of studies on grapeseed extracts;  as far as backing for the health benefits of authentic grapefruit seed extract is concerned, there really is almost none.

No historical use

In our article in 2010 in Herbalgram ​(ABC’s periodical publication) we could find no historical use in any traditional system of medicine to support the benefits of grapefruit seed extract,​ Mark Blumenthal, founder and executive director of ABC, told NutraIngredients-USA.

Nevertheless, the product has been on the market for a number of years with claims toward antimicrobial activity.  It appears that whatever antimicrobial activity these products might have had could be attributed to the presence of synthetic antimicrobial constituents in the products, which, because they are not disclosed on labels, fall into the category of adulterants.

There are still grapefruit seed extracts on the market.  Nature’s Way has one, for example, which makes a generic claim of ‘supports intestinal health.’ So, even with thin backing in terms of evidence, there is a need to be able to verify the products that are out there.

There is not much with regard to evidence for benefits if you use grapefruit seed extracts,​said Stefan Gafner, PhD, ABC’s chief science officer. The data out there is really scarce.  There have been one or two studies that show that these extracts have some but very low antimicrobial activity.  If you have a grapefruit seed extract that shows really strong antimicrobial actiivty it might be adulterated.

Gafner penned a recent paper with coauthors that included Ikhlas Khan, PhD​, head of NCNPR.  That study sought to characterize the limonoids and flavonoids in grapefruit seed extracts and other citrus products and the method therein forms part of the lab guidance document.

This method also permitted detection of synthetic preservatives such as benzethonium chloride, methylparaben, and triclosan in commercial grapefruit seed extract products. Out of the 17 commercial products analyzed, two contained the synthetic antimicrobial agent benzethonium chloride,​ Gafner and his co-authors wrote.

Quality control aid

The Botanical Adulterants Program’s lab guidance documents are intended for quality control personnel and lab technicians in the herbal medicine, botanical ingredient, dietary supplement, and food sectors of industry to help them choose the most appropriate techniques and methods for their specific analytical needs. They provide reliable, expert guidance on suitable methods to comply with the mandate to establish identity as an integral part of the testing requirements (identity, purity, strength, and composition) outlined in the US Food and Drug Administration’s (FDA’s) current Good Manufacturing Practices (cGMPs)​ for dietary supplements and/or conventional foods, as well as government-mandated cGMPs in other countries.

The changing nature of the antimicrobial compounds used to adulterate various batches of GFSE complicates the selection of an appropriate analytical method. A non-targeted approach, which means the use of a method where the compounds to be analyzed are not known, is required for the detection of these adulterants. Due to their ability to identify the presence of synthetic microbicides at low concentrations, GC-MS and HPLC-MS are particularly well-suited to meet the challenge,​ Gafner said.

As we have noted previously, adulteration of grapefruit seed extract with synthetic industrial disinfectant chemicals is a particularly egregious practice,​Blumenthal said.We believe that this should be the subject of appropriate regulatory action by the FDA.

To view this most recent lab guidance document, click here.

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