Essential Oils in Colour – Caddy Classic Profiles by Rosemary Caddy - Amberwood Publishing Ltd (1997)
…and its place in the Functional Group Hypothesis.
Tony Burfield Dec 2004.
Caddy Classic Profiles are basically a series of brightly coloured pie-charts of
90 essential oils commonly used in aromatherapy, broken down according to the
proportions of the functional groups of the constituent molecules. The
functional groups are divided down into esters (blue), aliphatic aldehydes
(indigo), ketones (light blue), sesquiterpenes (green), lactones & coumarins
(dark grey-green), oxides (canary yellow), acids (chrome yellow), aromatic
aldehydes (brown), monoterpenes (orange), alcohols (red) and phenols &
phenolic ethers (purpley-red). Each essential oil gets a one-page entry in the
book, which includes an interpretation of the pie-chart.
page 1-7 of the sixteen page introduction, Caddy refers to Pierre Franchomme’s
work where chemical constituent molecules of the essential oils were sprayed
between “electromagnetic” plates. According
to Caddy, the findings supposedly show an ordering of chemical families
according to the “solubility (presumably referring to lipophilicity/hydrophilicity)
and magnetic attraction” (presumably relating to electrophilicity/nuclephilicity
or electron receiving/donating abilities) of the families. Few with any
knowledge of electrochemistry would think this work has any redeeming value - as
I have remarked elsewhere, considering the actual specifications of the
components of the circuitry used, the experiment is more likely to have been
measuring static, or, with any luck at all, have been tuning into to amplitude
fluctuations in the signals of Radio Paris.
regarding the component ordering, Caddy decided aliphatic aldehydes and ketones
generate “more negative particles” – hence the blue colouring, whereas
oxides, acids, aromatic aldehydes, monoterpenes, alcohols and phenols generate
“more positive particles” and are coloured yellow to red. “Neutral
particles” represented by sesquiterpenes, lactones and coumarins are coloured
in shades of green.
hypothesis that the inherent properties of functional groups of the major
constituent molecules of essential oils could explain the therapeutic properties
of essential oils continued in the teachings of his own French school, and he
influenced other aromatherapy teachers such as Rodolphe Baltz, who describes the
therapeutic properties of over 200 essential oils in The Healing Power of
Essential Oils. The theory was further
advanced by Franchomme and Penoel’s major pharmacological work in French
- never translated into English - l'Aromatherapie Exactement pub.
Jollois (1990) ISBN 2-87819-001-7. By now a number of French & English
schools were teaching the principles
of the hypothesis, and the Franchomme school of thought was further advanced by
Kurt Schnaubelt (of the Pacific Institute of Aromatherapy) in the USA who
went on to market the very successful Advanced Aromatherapy
published by Healing Arts Press (English translation in 1998) ISBN
0-89281-743-7, which describes the hypothesis in a highly graphical manner
over pages 51-95. In a key statement on page 52, Schnaubelt acknowledges
Franchomme’s contribution to aromatherapy which he describes as “…to
acknowledge the impact that the tendency to donate or subtract electrons has on
the properties of an essential oil component”.
The problem is, that in the simplistic form that the
hypothesis tends to get reduced to, by some aromatherapy teachers – aldehydes
are anti-inflammatory, ketones are toxic etc. etc. – and this is, in my view,
complete bollocks. I was later to review the Schnaubelt book with S.
Sheppard-Hanger in the IJA 9(3) p
139, but previously Robert Tisserrand, then editor of the IJA, threw down
the gauntlet to Schnaubelt in the form of an editorial in IJA 9(2), challenging him to offer one shred of
scientific evidence that the “theory” actually works. Schnaubelt
subsequently gave a somewhat weak reply in IJA 10(2) p 62-3 suggesting that the true origin of the
hypothesis (rather than theory) lay originally with the chemical classifications
by the French fragrance companies Charabot & Dupont. He further implied that
the functional hypothesis does not explain all the properties of essential oils,
but is observed more favourably in monoterpenoids where lipophilicity and
electrophilicity/nucleophilicity can be important. Schnaulbelt conceded that the
“one-dimensional pharmacology” involved (with the functional group hypothes)
was limiting, and that aromatherapy conceivably works through the action of
hundreds of components, including the minor ones. It’s a pity that these
admissions were not included in Advanced Aromatherapy – instead the
footnotes to Franchomme’s original work remark that the results are not
undisputed, but he argues that the model is convincing and that they (the
results) “…establish a sensible if somewhat rough system of oils and their
qualities which has proven itself empirically over the past ten years”.
Penoel also defended the molecular functional
approach in IJA 9(4)
p162-3 conceding the reportage of the ‘molecular approach’ had resulted in
an oversimplified and generalised approach. For example, he remarks that the
statement that all ketones are neurotoxic is now not agreed. However Penoel
remarked that the approach offered more advantages than drawbacks. Penoel goes
on to distinguish between three systems: single oils, horizontal functional
molecular synergies between essential oils (blending oils with similar
functional groups) and vertical functional molecular synergies (blending oils
with different functional groups).
With all this discredit as a background, it is
surprising that the functional group hypothesis still remains a central part of
aromatherapy dogma today, to the extent that this little popular high street
book was muted as a set book for aromatherapy students to study, in the initial
proposal by the collective wisdom of the Syllabus Committee of Aromatherapy
Consortium 2004. What hope for aromatherapy if its would-be regulators do not
keep up with events in modern aromatherapy thought?
Back to Caddy
This poorly referenced book was reviewed in 1998 by
Robert Tisserand (IJA 9(1)
p43-44) who severely criticised it, concluding, "nature is far more complex
than this pseudo-scientific work would have us believe".
Dipping into the pages at random, under lavender true
(p 42), we find it incorrectly described as Lavandula augustifolia (its angustifolia)
and is incorrectly described as being distilled from the stalks (lavender stalk
oils are harsh, and inferior to ‘normal’ oils from the flowering tops). The
oil is mentioned as possessing stimulant (?) & sedative properties, which,
double checking with Tisserand’s review (referenced above), was also queried
by him. Worse than this in the introduction on 1-5, the same oil is featured
where “the large proportion of alcohols will have good stimulating
properties…”. The basis for this seems to be that in section 1-14 of the
book, alcohols are said to be stimulant. Yet linalol is clearly a well-proven
CNS depressant… Tisserand picks up on the fact that Caddy adds the rider in
part 1-14 that some sesquiterpenols and aromatic alcohols may be calming.
However linalol is not an aromatic alcohol! So we see that with one of the most
heavily used aromatherapy raw materials, Caddy’s theories are already in
If the hypothesis were to be given the best chance to
demonstrate that it works – it should surely be in those cases where a single
component dominates the composition of the oil. We could imagine that
wintergreen oil (97% methyl salicylate), rosewood oil (to 95% linalol),
palmarosa oil (to 85% geraniol), cinnamon leaf oil (86% eugenol) could provide
examples here. However according to Caddy we see rosewood and palmarosa oils as
stimulants, and cinnamon listed as aphrodisiac (I regret to inform
readers that there is no scientific evidence for this!).
Several urban myths are repeated in the book – that
for example Rosemary and Fennel oils should not be used with epileptic patients
– although there is no proof that this is so. Cedarwood oils Virginian or
Texas should be avoided in pregnancy – there is currently no scientific basis
for this either. Lemongrass oils (East and West India) are reported to contain
‘aliphatic aldehydes’ – a confusing term which is better replaced by
acyclic monoterpinic aldehydes to avoid confusion with straight chain aliphatic
aldehydes such as 1-decanal. Where
there should be appropriate hazard/risk cautions – these are missing – e.g.
for Cade oil (i.e. only the redistilled oil should be used), for Hyssop oil
(toxicity) or for Grapefruit oil (said to be non-photo-toxic whereas
there is a quantifiable risk).
The most unfortunate part of the book is the risk of
literal translation of the general properties of the chemical families for the
specific oils in question, e.g. all lactones and coumarins are calming,
sedative, uplifting (nervous system), all lactones and coumarins are
anticoagulant, lower the blood pressure, are decongestant (circulation and
immune system). Although there is a qualifier (“individual chemical
constituents may exhibit some of the characteristics of the family they
belong to…”) one is left wondering why bother with the system at all.
Future Direction for the Hypothesis
Although Schnaubelt, Penoel and others vaguely refer
to molecular structures attached to functional groups as being important, the
only person to impress me in advancing the functional group hypothesis further
is probably Joy Bowles. If I remember correctly when I met her a few years back,
Bowles indicated that the functional hypothesis is far more credible if specific
molecular structures associated with, and in proximity to the functional group
are also considered. I agree with this, since for example we know that certain
sesquiterpene lactones are sensitising because they carry an alpha-methylene
butrylactone structure which is held in common with other sensitising
substances occurring in costus oil, laurel leaf oil, feverfew oil etc.
This is getting a bit complicated....but may better fit the known
characteristics of certain
essential oil properties. Paraphrasing Penoel’s comments in the article quoted
above, about a the relevance of a holistic approach to essential oil
therapeutics, and the comments by Tisserand complaining that the functional
group hypothesis in any case does not account for synergistic and antagonistic
effects of essential oil components, probably means that the whole hypothesis is
now credited with limited value. It is far more important to establish the
therapeutic properties of essential oils per se, without their attempted
interpretation by simplistic theories.
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