Professor Gerhard Buchbauer (Vienna, Austria) continued the theme of the pharmacological
basis of claims made for efficacy of volatile oils. He emphasised the difference
between aromatherapy, in which a distinct physical effect could be observed,
and aromachology, where the effect was, at least to some extent, a psychological
reaction to the odour of the essential oil. The two were often connected, such
as when a good feeling, induced by a pleasant smell, resulted in a general relaxation
of muscles. He also cited studies showing that effects were often related to
expectations.
There was, however, some evidence for a direct therapeutic effect, and in some
cases the constituents responsible had been isolated and shown to have comparable
activity. Thus the sleep-inducing properties of hop pillows had been shown to
be due to 2-methyl-3-buten-2-ol, while 1,8-cineole in rosemary oil had been
shown to increase motor activity and blood supply to the central nervous system,
revealed by xenon radiodiagnosis computer-aided tomography of patients.
Conversely, linalool from lavender oil showed a decrease in activity, particularly
after the animals tested had been over-agitated by a dose of caffeine. Stress
and travel-sickness in pigs had been reduced by using lavender straw for their
bedding while in transit.
Professor Buchbauer also quoted work that had shown that repeated massage with
oil had resulted in an accumulation in the tissues. Limonene had a half-life
of 54 hours, so there was the possibility of toxic doses in the bloodstream
being reached if frequent massage with oils containing this terpene occurred.