Aromatherapy…n. The use of aromas for their healing properties

Translated literally, aromatherapy means the use of aromas for their healing properties. There are various definitions of aromatherapy and essential oils.

According to Shirley Price, a respected authority on aromatherapy:[1]

"Aromatherapy is the controlled use of essential oils to promote the health and vitality of the body, mind and spirit by inhalation, baths, compresses, topical application and full-body massage. The definition of aromatology (i.e., complete aromatic medicine) is the controlled use of essential oils to promote the health and vitality of the body, mind and spirit by inhalation, baths, compresses, topical application (as above) and selected area massage, plus external intensive use of undiluted oils and internal use via rectum, os[2], and vagina."

In advanced aromatherapy courses, we will cover oral administration, but it is outside the scope of the program to cover vaginal or rectal administration. The focus of the ACHS aromatherapy program is holistic aromatology. Holistic aromatology focuses on restoration of physical, mental, emotional, and spiritual health through the application of essential oils. We use the terms "aromatherapy" and "aromatology" interchangeably throughout our materials, but wanted to provide the distinctive definition above to give you a better understanding of how it may be used elsewhere.

Holistic aromatherapy focuses on restoration of physical, mental, emotional, and spiritual health through the application of essential oils.

All healing modalities taught by the American College of Healthcare Sciences focus on the holistic approach. Our philosophy is that wellness can only be achieved by taking care of the whole person including our physical, mental, emotional, and spiritual selves.

Practical Exercise

First, take a minute to think about how you define aromatherapy.

Now, see how others define aromatherapy. Review any texts or magazine articles that you have, or look for definitions of aromatherapy online. What are some key words that are commonly used? How do the definitions you have reviewed compare to your initial thoughts?

What Is An Essential Oil?

An essential oil is the distilled (or sometimes expressed) product of the volatile components synthesized by various plant tissues of a single plant species.

AFNOR, a French organization, defines an essential oil as:

A volatile derivative obtained from botanical raw material by either steam distillation, mechanical processing of the pericarp of citrus fruits or by dry distillation. The essential oil is then separated from the aqueous phase by physical means.

The term essential was applied to these oils because they contain the essence, or fragrant part of the plant. The alchemist Paracelsus (1493-1541) coined the word "essence", which equates to spirit (in alchemy, spirit is the personality or extract of something that retains the qualities of the original substance). Essential oils are also referred to as the "blood" of the plant. Note that this is descriptive and is not botanically correct: Essential oils should not be confused with the sap or phloem of a plant.

An essential oil consists of sometimes hundreds of individual biochemical components. Each component possesses specific characteristics and properties directly relating to its molecular structure. The relatively small number of chemical groups can be classified according to chemical structure and function, such as esters, terpenes, and alcohols. It is the unique combination that provides such a diverse range of healing actions in the body. The properties and effects of the whole essential oil are often more than a sum of these component parts and are highly individual and unique, reflecting the synergy between the constituents of each oil.

A Long History

The documented use of essential oils goes back to Egyptian times when they were used for embalming purposes. Essential oils were found in Egyptian tombs, and it is known that herbs were regularly burnt in public squares to purify the air. During the eighth century, the Arabs improved the distillation process and made extensive use of essential oils in ointments and elixirs. Many of their recipes survived into the middle ages.

René-Maurice Gattefossé (1881-1950) is credited with coining the term aromatherapy. Gattefossé was a French chemist and a perfumer who worked with his father in their business of importing essential oils and creating exotic perfumes. Between 1906 and 1912, the perfume industry flourished in France as great quantities of lavender, clary sage, and mint were cultivated and distilled. Gattefossé was a prolific researcher and writer and in 1937 he published Aromatherapie and Antiseptiques essentielles (Essential antiseptics). He researched the dermatological effects of essential oils, which encouraged the rapid growth of the beauty, cosmetic, and skin care industries. His interest in the therapeutic uses of essential oils was stimulated by a personal accident in his perfumery laboratory where he severely burned his hand. He was astonished at how quickly it healed after plunging it into a container of lavender. Gattefossé's work inspired a number of researchers and writers in the 1950's and 60's. We look more at aromatherapy history in more advanced courses.

Quick Self-Check for Understanding:

Q: Who coined the term "essence"?

Scroll down to reveal the answer:

Volatility

A Key Feature of Essential Oils

All essential oils are volatile. The word volatile comes from the Latin word volare, or "to fly". The term volatile is applied to essential oils because they evaporate when exposed to air, even at normal room temperatures, and become vapor. Rates of evaporation vary among essential oils.

We are used to using vegetable oils, such as olive, canola, or safflower. These oils are also called fixed or base oils. They are very different from essential oils. They feel oily to the touch and when exposed to air they become rancid and do not evaporate. By contrast, essential oils are not oily, do not leave an oily residue, do not become rancid, and they evaporate readily.

A volatile substance:

• Has the ability to diffuse freely into the atmosphere
• Is easily vaporized at low temperatures

Volatile is also an umbrella term for low boiling-point components of a natural source of aroma or flavor.

Volatility is defined as the speed or rate at which a substance evaporates when exposed to the air.

The nature of the aromatic components in essential oils is that they are predominantly volatile, meaning their constituent molecules possess enough inherent energy to allow them to lift up into the air naturally. They all generally have high Brownian movement.[3] If more energy is put into the system, (i.e., you warm them up) they become more volatile and leap into the atmosphere more readily. For example, if you heat ice, it melts, and heating it further will turn it into steam.

Each component molecule of a single essential oil (or absolute or expressed essence) has its own volatility by virtue of its shape and molecular weight. Larger, heavier molecules are less volatile and they often hold back the lighter, smaller ones. Likewise, the small energetic molecules often take the heavier ones along with them.

How Does Volatility Relate to Therapeutic Uses?

Essential oils are administered in various ways. If used externally, in massage oil or when inhaled, the active constituents found in the oil are absorbed into the bloodstream via the skin and the mucous membranes in the nose. Active constituents are the chemical components that give the oil its unique range of action. We will study these processes in detail in this program.

How Does Volatility Relates to the Perfumery Notes?

In perfumery, the concept of volatility generated the classification of aromatic materials into top, middle, or base notes.

When you apply perfume or cologne or any fragrance onto your skin, or even as you sample those little testers they have at the perfume counters, you know that the aroma character or impression will change as it evaporates into the air over time. Similarly, when you dip a smelling strip into a bottle of essential oil, which may have hundreds of individual components each with different concentrations, shapes, weights, and attractions to one another, they will evaporate at different speeds or levels of volatility.

This means that some aromas last longer than others do. They have greater persistence, and in fact, some have such tenacity and persistence that they are employed as fixatives, to hold some of the less persistent components of a fragrance in order to prolong its perfume.

Sandalwood oil is an example of a fixative. The ancient Ayurvedic classic creation of "Aytar" blends sandalwood with rose, and hydrogen bonding is seen between the molecules of santalol in sandalwood and rose alcohols.[4]

Why does this happen? Well, the speed at which fragrance components evaporate is dependent on their specific weight and energy. Heavier, slower moving molecules, such as those in sandalwood, will generally take longer to diffuse into the atmosphere. In addition, some are influenced by their chemical attraction to other components.

In fact, there is evidence to suggest that molecules of certain chemical classes attract one another more than might be expected from the simple forces of cohesion usually found in liquids. Apparently, what happens is that bonding takes place between the hydrogen atoms found within molecules of certain chemical families.

In his book The Chemistry of Essential Oils, David Williams says that:

"The effect of hydrogen bonding among polar constituents of a liquid essential oil (i.e., the oxygenated constituents) is a tendency for smaller, faster moving molecules of relatively low molecular weight to be held back within the body of the liquid by larger, heavier molecules. We may also speculate that lighter polar molecules moving towards the surface of the liquid exert some pulling effect on heavier, polar molecules, tending to assist their movement towards the surface and so promoting their evaporation." [5]

This phenomenon, explains Williams, is thought to bring about the "wonderfully coherent odors of flower absolutes", such as lavender absolute and jasmine absolute. This "naturally produces blending effect for which hydrogen bonding is doubtless at least partially responsible."

Williams also points out that:

"The fixative effect of certain perfume ingredients in prolonging the duration of the fragrance of a perfume can, in part, be attributed to hydrogen bonding, although the presence of larger molecules in a liquid mixture of volatiles must certainly impede the evaporation of smaller ones, so exerting a purely mechanical fixative effect."

Top, Middle, and Base Notes

Components or blends of essential oils that are highly volatile are said to be or possess top notes. They are light, sharp, uplifting, short lived and immediate. Bergamot, neroli, and ginger are examples of top notes, or essential oils with many top note components.

Components or blends of essential oils that have heavier, more complex molecules are said to be middle notes - they last longer, are perceived after the top notes have faded, and are considered balancing. Middle notes make up the core - or heart - of the blend or essential oil. They are often called modifiers. Chamomile, geranium, and rosemary are examples of essential oils with many middle note components.

Components or blends of essential oils that are the heaviest and most complex are said to be base notes. They are tenacious, fixative, and pervasive. They carry the blend or are the last note to be perceived in a single essential oil. They are considered to be grounding and make the foundation of a blend. Sandalwood, patchouli, and clary sage (shown right) are examples of essential oils with many base note components. They have excellent holding power for a blend.

We will study this concept again and look at the types of components in detail.

Continue on to Part Two of this lecture.

Notes and References

[1] Price S, Price L. Aromatherapy for Health Professionals 2nd Ed. Philadelphia: Churchill Livingstone; 2000:268.

[2] "Os" is defined as meaning mouth or any body orifice.

[3] Brownian \Brown"i*an\. a. Pertaining to Dr. Robert Brown, who first demonstrated (about 1827) the commonness of the Brownian movement described below. Brownian movement: The peculiar, rapid, vibratory movement exhibited by the microscopic particles of substances when suspended in water or other fluids. Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.

[4] Williams D. Chemistry of Essential Oils, page 269.

[5] Williams D. Chemistry of Essential Oils, pp. 116-117.