This information came up on a cosmetics list where lots of attention is
given to how substances are extracted and preserved. It looks by these
studies as if the antimicrobial action commonly attributed to GSE is in
fact caused by chemicals used to process it. I don't like it either, but
people need accurate information.
Deborah
*************
Identification of benzethonium chloride in commercial grapefruit seed
extracts.
Takeoka G, Dao L, Wong RY, Lundin R, Mahoney N.
J Agric Food Chem. 2001 Jul;49(7):3316-20.
Western Regional Research Center, Agricultural Research Service, U.S.
Department of Agriculture, 800 Buchanan Street, Albany, California 94710,
USA. [email protected]
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, nuclear magnetic resonance (NMR) spectroscopy, and
elemental analysis (by proton-induced X-ray emission [PIXE] analysis). The
main constituent was identified as benzethonium chloride, a synthetic
antimicrobial agent commonly used in cosmetics and
other topical applications. This compound comprised 8.03% (n = 2) of the
liquid GSE sample. Higher amounts of benzethonium chloride were found in
powder GSE samples.
--------------
Aspects of the antimicrobial efficacy of grapefruit seed extract and its
relation to preservative substances contained.
von Woedtke T, Schluter B, Pflegel P, Lindequist U, Julich WD.
Pharmazie. 1999 Jun;54(6):452-6.
Institute of Pharmacy, Ernst Moritz Arndt University, Greifswald, Germany.
The antimicrobial efficacy as well as the content of preservative agents of
six commercially available grapefruit seed extracts were examined. Five of
the six extracts showed a high growth inhibiting activity against the test
germs Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16, Staphylococcus
aureus SBUG 11, Serratia marcescens SBUG 9, Escherichia coli SBUG 17,
Proteus mirabilis SBUG 47, and Candida maltosa SBUG 700. In all of the
antimicrobial active grapefruit seed extracts, the preservative
benzethonium
chloride was detected by thin layer chromatography. Additionally, three
extracts contained the preserving substances triclosan and methyl parabene.
In only one of the grapefruit seed extracts tested no preservative agent
was
found. However, with this extract as well as with several self-made
extracts
from seed and juiceless pulp of grapefruits (Citrus paradisi) no
antimicrobial activity could be detected (standard serial broth dilution
assay, agar diffusion test). Thus, it is concluded that the potent as well
as nearly universal antimicrobial activity being attributed to grapefruit
seed extract is merely due to the synthetic preservative agents contained
within. Natural products with antimicrobial activity do not appear to be
present.
--------------
[Analysis of components in natural food additive "grapefruit seed extract"
by HPLC and LC/MS]
Sakamoto S, Sato K, Maitani T, Yamada T.
Eisei Shikenjo Hokoku. 1996;(114):38-42.
The components in a commercial natural food additive "Grapefruit seed
extract" and the ethanol extract of grapefruit seeds were analyzed by HPLC
and LC/MS. The HPLC chromatogram of the commercial grapefruit seed extract
was quite different from that of the ethanol extract of grapefruit seeds.
Three main peaks were observed in the chromatogram of the commercial
grapefruit seed extract. By comparison of the retention times and the
absorption spectra with those of authentic samples, two peaks were
ascribed to methyl-p-hydroxybenzoate and
2,4,4'-trichloro-2'-hydroxydiphenylether (triclosan). Triclosan was also
identified by LC/MS by using the negative electrospray ionization method.
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