ARS | Publication request: IDENTIFICATION OF BENZALKONIUM CHLORIDE IN COMMERCIAL GRAPEFRUIT SEED EXTRACTS

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2005
Publication Date: August 12, 2005
Citation: Takeoka, G.R., Dao, L.T., Wong, R.Y., Harden, L.A. 2005. Identification of Benzalkonium Chloride in Commercial Grapefruit Seed Extracts. Journal of Agricultural and Food Chemistry. 53:7630-7636.

Interpretive Summary: Grapefruit seed extract (GSE) is promoted as a natural product that has reported antibacterial and antiviral properties. It is reported to be safe and effective to use internally and externally for a wide variety of conditions such as acne, allergies, athlete’s foot, body odor, candida, colds, cold sores, gastrointestinal infections, gingivitis, impetigo, parasitic infection, sinusitis, sore throat and thrush. There is recent evidence that some commercial GSE samples are adulterated with synthetic preservatives and that these additives are solely responsible for the antimicrobial activity. Preservatives such as methyl 4-hydroxybezoate (methyl paraben), 2,4,4’-trichloro-2’-hydroxydiphenyl ether (triclosan) and benzethonium chloride have been identified in commercial GSE samples. In this study we identified a new synthetic adulterant, benzalkonium chloride, in commercial GSE samples. This ingredient is a synthetic antimicrobial agent that is widely used in cleaning and disinfection agents. The presence of benzalkonium chloride in a commercial product designated for internal and external use by humans is troubling in light of its toxicity and allergenicity.

Technical Abstract: Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high performance liquid chromatography, electrospray ionization mass spectrometry (ESI/MS) and tandem mass spectrometry (ESI/MS/MS), and elemental analysis (by proton induced X-ray emission [PIXE] analysis). Three major constituents were observed by HPLC and were identified as benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. This mixture of homologues is commonly known as benzalkonium chloride, a widely used synthetic antimicrobial ingredient used in cleaning and disinfection agents.