FWD 2 AHPA Adds Grapefruit Seed Extract to Known Adulterants List

HerbalEGram: Volume 9, Number 9, September 2012

AHPA Adds Grapefruit Seed Extract to Known Adulterants List

On July 26, 2012, the American Herbal Products Association (AHPA) announced the addition of grapefruit seed extract (GFSE) to its “Known Adulterants” list, making it the 14th herb to be recognized by the trade association as having established potential adulterants.1,2 Previous reports from AHPA and the American Botanical Council (ABC) detailing the presence of synthetic preservatives, disinfectants, and microbicides in GFSE provide credible scientific evidence in support of the adulteration claims.


“AHPA’s policy now identifies GFSE-labeled material as an article of trade that may be adulterated with benzalkonium chloride, benzethonium chloride, triclosan, methyl paraben, or any other synthetic antimicrobial agent,” said AHPA Chief Science Officer Steven Dentali, PhD (email, August 17, 2012).


In his comprehensive report on GFSE adulteration published earlier this year in HerbalGram #94, natural product, organic, and analytical chemist John H. Cardellina II, PhD, described GFSE as a natural antimicrobial agent that can be ingested or used topically. Supposedly derived from seeds of the common grapefruit (Citris x paradisi), GFSE has been described in the scientific literature as being used for a wide variety of conditions, including “eczema, acne, cold sores, athlete’s foot, sore throats, thrush, vaginal infections, colds, various gastrointestinal disorders and infections, allergies, and gingivitis.”3


In the article, Dr. Cardellina outlined the results of 10 published GFSE chemical analyses dating back to 1991. Various studies have detected the presence of synthetic microbicides, which in one case accounted for 22% of the tested extract’s weight. He concluded that “a significant amount, and possibly a majority, of ingredients, dietary supplements, and/or cosmetics labeled as or containing grapefruit seed extract (GFSE) is adulterated, and any observed antimicrobial activity is due to synthetic additives, not the grapefruit seed extract itself.”3


According to Dr. Dentali, adulteration of GFSE has been suspected for years. “AHPA has followed the scientific literature on GFSE and provided coverage with 3 annotated citations in the AHPA Report (July 2005, September 2005, and June 2006 issues), and contributed to the technical knowledge via a poster and a published analytical report in collaboration with the University of Mississippi [National Center for Natural Products Research; NCNPR] that came out in 2007,”4 he said.  


AHPA is currently compiling data on relevant analytical methods to aid manufacturers and quality control groups in detecting the presence of GFSE adulterants. “What might be preferred by one company may not be suitable for another. Above all, a method must perform as expected, which is the same thing as saying (and FDA does say this) that it has to be scientifically valid,” explained Dr. Dentali. Importantly, he continued, “The addition of this information to AHPA’s website does not change manufacturers’ legal obligations; they have always been responsible for assuring accurate identification of all their ingredients.


Methods for the analysis of GFSE are already available in the scientific literature, such as the reports summarized in Dr. Cardellina’s extensive, peer-reviewed article in HerbalGram. 


“We are pleased to see AHPA add GFSE to its list of Known Adulterants,” said ABC Founder and Executive Director Mark Blumenthal. “Many of us have known for a long time from numerous published analyses in the scientific literature that many ingredients labeled as ‘grapefruit seed extract’ are adulterated with synthetic industrial disinfectant chemicals. That is why the ABC-AHP-NCNPR Botanical Adulterants Program made a priority of covering this form of adulteration early in the Program. Now, with the official inclusion by an herbal trade association on its published list of adulterants, there is even a greater degree of industry recognition of this problem ingredient.”


The addition of GFSE to AHPA’s Guidance Policy on Known Adulterants comes less than a year after the November 2011 addition of Chinese star anise (Illicium verum), which is occasionally confused with the similar-looking — and toxic — Japanese star anise (I. anisatum).5 AHPA’s list of Known Adulterants, including entries for bilberry (Vaccinium myrtillis) fruit extract and black cohosh (Actaea racemosa) root and rhizome, can be found online in the "Guidance Policies" section

More information about the ABC-AHP-NCNPR Botanical Adulterants Program can be found on ABC’s website.



1.    AHPA adds grapefruit seed extract to list of known adulterants as part of its botanical authentication program [press release]. Silver Spring, MD: American Herbal Products Association. July 26, 2012. Available at: www.ahpa.org/Default.aspx?tabid=69&aId=805. Accessed August 16, 2012.


2.    Known adulterants. American Herbal Products Association website. Available at: www.ahpa.org/Default.aspx?tabid=223. Accessed August 16, 2012.


3.    Cardellina JH. The adulteration of commercial ‘grapefruit seed extract’ with synthetic antimicrobial and disinfectant compoundsHerbalGram. 2012;94:62-66. Available at: http://abc.herbalgram.org/site/R?i=DYy5tBYQ-KcB7yR20SGCNg. Accessed August 17, 2012.


4.    Avula B, Dentali S, Khan IA. Simultaneous identification and quantification by liquid chromatography of benzethonium chloride, methyl paraben, and triclosan in commercial products labeled as grapefruit seed extract Pharmazie. 2007;62(8):593-596.


5.    ABC, AHP, and AHPA provide identity information on star anise confusion [press release]. Austin, TX: American Botanical Council. November 17, 2012. Available at: http://cms.herbalgram.org/press/2011/ABC_AHP_AHPA_Provide_Identity_Information_on_Star_Anise_Confusion.html. Accessed August 20, 2012.