Complementary Alternative Cardiovascular Medicine

Chapter 15 / Aromatherapy and CVD 245
skin. Some essential oils may cause dermal irritation and are better used
by inhalation.
Essential oils should not be confused with herbal extracts, and the two
substances cannot be used interchangeably. Herbal extracts are diluted
and are often taken internally. Essential oils are concentrated and are not
usually taken internally.
A good knowledge of plant taxonomy is important if the correct oil is
to be used. Many essential oils have the same common names. Lavender
is a common name that covers three different species of lavender and
countless man-made hybrids that cannot be used interchangably. The
botanical name indicates exactly which lavender by using the genus
(rather like a surname) and the species (rather like a first name). The
genus of lavender is Lavandula, and all lavenders begin with this word.
L. angustifolia is possibly the most used and researched essential oil
and is recognized as a relaxant. However, the other two species of lavender
have different properties. L. latifolia (Spike lavender) is a stimulant,
expectorant, and mucolytic. L. stoechas is antimicrobial but should
not be used for long periods of time, because it contains a large percentage
of ketones, which can build up liver toxicity (18). For aromatherapy
to be used clinically, it is important to know the full botanical name of
an essential oil. Please see Table 2 for a list of the botanical names of
essential oils referred to in this chapter and Table 3 for examples of plant
identification.
CLINICAL AND SCIENTIFIC STUDIES AND EVIDENCE
MRSA
Essential oils were used before synthetic antibiotics and antiseptics.
Most essential oils and components of essential oils have some antibacterial,
antifungal, or antiviral properties, and a large number of studies
have indicated their effectiveness in vitro (19–21). Peppermint, thyme,
lavender, tea tree, and juniper essential oils are effective against MRSA
in vitro (22). A further article (23) also showed that Melaleuca
alternifolia (tea tree) was effective against MRSA in vitro. It was tested
against 64 methicillin-resistant and 33 mupirocin-resistant isolates of
S. aureus and was effective in all cases, using dilutions of 0.25% and
0.50%. These results were duplicated in a UK study using similar methods.
Chan and Loudon (24) conducted a further in vitro study on 28
isolates of MRSA and eight clinical isolates of coagulase-negative staphylococci
at Manchester Royal Infirmary, England. The minimum
inhibitory concentrations (MICs) were repeated three times and ranged
from 0.25–0.5% tea tree. No resistant isolates were found. Many cos-