Adulterated honey raises more than just questions!

1
Adulterated honey raises more than just questions!
Analytical Unit, St Georges - University of
London, UK
Susannah Kenyon, Jennifer Button, Denise A.
McKeown, Terry D. Lee and David W. Holt.
Results
Case
Screening
Introduction
A reference standard was prepared by mixing a
reference blank honey (purchased from
Sainsburys PLC) with deionised water containing
sildenafil (50mg/L), tadalafil (10mg/L) and
vardenafil (16mg/L). The honey samples and a
blank were prepared by mixing with deionised
water. Diluted standards, blanks and samples
were analysed using a Perkin Elmer Lambda 35
UV/VIS spectrometer (Wellesley Mass), scanning
across a UV wavelength range 190-400nm. Diluted
standards, blanks and samples were also extracted
using pH7 buffer into MTBE, evaporated under
vacuum, reconstituted in 80 methanol and
injected onto the LC system. A Perkin Elmer
Series 200 pump, autosampler and column oven was
used. Chromatography was achieved on an Alltech
Alltima C18 (150 x 2.1mm, 5µm) column maintained
at 50C. The mobile phase contained
methanoldeionised water (8020 v/v), with
ammonium formate added to achieve a final
concentration of 2mM. Mass-spectrometric
detection was performed on a Sciex API2000 triple
quadrupole equipped with a turbo-ion spray
interface (Applied Biosystems) held at 400C.
Nitrogen was used as collision gas. Positive
ionisation was used, and the extracts were
analysed using both product ion scan and
multiple reaction monitoring (MRM) mode. The
precursor ions MH for sildenafil, tadalafil
and vardenafil were m/z 475, 390 and 489
respectively. Product ions used were sildenafil
(m/z 58, 100, 283 and 311), tadalafil (m/z 268
and 204) and vardenafil (m/z 151 and 312).
Herbal remedies as prophylaxis and treatment of a
variety of ailments have been sought after and
used for centuries. Herbal medicines and
remedies for the treatment of impotence are
widely available from Internet sites that promote
them as safe, herbal alternatives and 100
natural products.1,2 In the United Kingdom there
are 3 phosphodiesterase type 5 inhibitor drugs
available on prescription to treat impotence
sildenafil, tadalafil and vardenafil.3 Numerous
Internet sites also claim to sell these
drugs.4 Herbal alternatives to impotence drugs
are becoming increasingly popular as they appeal
to individuals who are unable to take
phosphodiesterase inhibitors. Herbal products
for the treatment of erectile dysfunction have
been found to contain sildenafil and tadalafil
before.5,6 A recent news article reported an
Israeli beekeeper claiming that his bees that
feed on a local flower called Zallouh on Mount
Hermon on the borders of Israel, Syria and
Lebanon, can produce honey that improves libido
and fertility.7 The plant is known locally as
Lebanese Viagra and its key ingredient is
ferula hermonis, a recognised aphrodisiac8,9.
A 50-year-old man was introduced to the herbal
honey by a friend. The patient reported good
clinical efficacy to his GP, who became
suspicious about the contents of the product.
Two jars of honey were sent to the Analytical
Unit for toxicological analysis (one used by the
patient the other remained sealed). The
manufacturer of the honey product was identified
as Etumax and a similar product was purchased
directly from the Etumax website10. Sachets (12 x
20g) of Royal Honey were received in a
presentation box at a cost of 55 plus 10pp.
Overall packaging and description of the product
were similar to those used by the patient (figure
1). The listed ingredients in the purchased
honey were Radix Eurycoma longifolia Extract
(200mg), Radix Panax Ginseng powder (200mg), Bee
Larva Powder (200mg) and pure honey (19.4g).
Screening indicated that both jars submitted by
the patient and all sachets analysed, were
positive for sildenafil. Tadalafil and
vardenafil were not detected in any honey samples.
Quantitation of the contents revealed a mean
concentration of 59mg of sildenafil per sachet
(20g of honey). Figure 3 shows the variation in
content within and between sachets analysed.
Methods
Pure reference standards of sildenafil (Viagra),
tadalafil (Cialis) and vardenafil (Levitra) were
generous gifts from Pfizer, Lilly and Bayer,
respectively. Two jars of honey bought by the
patient and 6 of 12 sachets purchased by the
Analytical Unit were analysed. Aliquots of the
jar honey (5g), and the entire contents of each
of the sachets (20g) were screened by scanning
ultra-violet spectrophotometry (UV) and liquid
chromatography with tandem mass-spectrometric
detection (LC/MS/MS). The contents were
quantified using LC/MS/MS.
Figure 3 Sildenafil contents of the 6 sachets of
honey analysed (3 aliquots of each, injected in
duplicate). Overall mean was 59.4mg of
sildenafil per sachet.
Conclusions
It is concerning to find another product, being
sold as a herbal treatment for impotence,
containing a prescription only medicine. It is
also unusual being a food product, that may be
consumed unsuspectingly. This is the second
product sold by Etumax that has been found to
contain sildenafil5. Unlike the previous
product, it contained only sildenafil and no
other phosphodiesterase type 5 inhibitor.
Sildenafil was also found in quantities (59.4mg
per sachet), that would cause a notable
pharmaceutical effect or interaction (typical
dose 50-100mg per day3). Our findings further
demonstrate the potential dangers for patients
taking natural or herbal products that are
not under the control of a regulatory agency.
Quantitation Sildenafil calibrators were
prepared in deionised water over a concentration
range 10-500ng/mL. Honey samples (entire sachet
contents 20g) were diluted 1 in 100 with
deionised water. 3 separate aliquots from the
initial dilutions were taken and diluted a
further 1 in 10,000 with deionised water. As a
result the honey samples (diluted 1 in 1,000,000)
were effectively aqueous solutions of sildenafil,
therefore matching the calibrator matrix.
Standards, blanks and samples were then injected
in duplicate directly onto the LC/MS/MS system.
Only the sachets of honey were quantified.
The case described here involves the use of honey
claiming to be herbal and sold to improve
fertility and cause distinguished sexual
activity. The product listed no prescription
drugs among its ingredients.
References
6. Fleshner N, Harvey M, Adomat H, Wood C,
Eberding A, Hersey K and Guns E. Evidence for
contamination of herbal erectile dysfunction
products with phosphodiesterase type 5
inhibitors. J Urol. 2005 Aug174(2)636-41 7.
Matti Friedman. Guardian Sep 30, 2007.
www.guardian.co.uk 8. K. A. Hadidi, T. Aburjai
and A. K. Battah. A comparative study of Ferula
hermonis root extracts and sildenafil on
copulatory behavious of male rats. Fitoterapia.
2003 Apr 74(3). 9. Ferula Hermonis Discover the
Lebanese Viagra that can Restore Your Libido
and Sexual Potency found at www.thehealthierlife.c
o.uk/article/3691/ferula-hermonis-impotence.html.
Accessed 4-Oct 2007. 10. Etumax website
wwwetumax.com accessed 16 Oct 2007.

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