Answer A: Aromatherapy literature insists any Essential Oil can cross the blood brain barrier. I do not see why frankincense should be an exception, it has similar components to many other essential oils.

Answer B: The blood-brain barrier is a semi-permeable barrier produced by cells in the capillary walls in the brain (the cells in the capillaries in the brain have no gaps between them unlike the capillaries elsewhere in the body) The function of the blood-brain barrier is to protect the composition of the fluid that bathes the neurons, if this changes appreciably then the brain cannot function normally. The blood-brain barrier is not uniform through the CNS so that free passage can occur at some parts i.e. the area postrema part of the medulla.

Olibanum oil (aka frankincense oil) is derived from several different species of Boswellia according to geographic origin, and often alpha-pinene (to 43%) is the principle component. Other terpenes and sesquiterpenoids such as viridiflorol add to the characteristic odour. Larger molecules cembrene and incensol are characteristic of fine aspects of characteristic olibanum odour.

Low molecular weight lipophilic substances such as the components of many essential oils are able to pass through the blood-brain barrier, there is nothing particularly exceptional about olibanum oil in this regard, although of course the pharmacological properties of olibanum have been legendary throughout the Centuries, so maybe at one time this was considered more significant than now.

Comment from NAHA Director:

I had a physician at the med center ask me if I would teach medical students an aromatherapy class as a prior person had made claims based on information received from a distributor of essential oils, that oils would cross the blood brain barrier, correct scoliosis and replicate DNA. This is what makes it very difficult to integrate aromatherapy into medical systems (my goal) and be taken seriously.

I had worked with him for some time and couldn't understand until he shared this info what is resistance was to aromatherapy.

Thank you to the Safety Committee for this valuable information- Pam Conrad RN, BSN, CCAP

There is no proof that essential oils compromise the immune system. Immunotoxic materials are known but do not include essential oil components.

Much of this is unfortunately based on misconception. The Internet especially is full of features on nebulizers with misleading statements such as: "nebulizers can supply greater therapeutic benefit than the use of other diffusers because they break the oils down into smaller molecules".This is the incorrect use of the word "molecule".

A nebulizer is a dispensing device which physically breaks up an existing liquid into tiny droplets which can appear as a very fine mist . Although we sometimes use the term "atomiser" to describe this process, although the actual break up of the constituent molecules in the aromatic material to atoms has nothing to do with it -the molecules remain intact.

A diffuser for natural aromatic substances on the other hand usually involves the evaporation of liquid from a surface - whether this be via essential oil-impregnated paper strips, or from a hot glass or ceramic surface such as you would might find in an aromatherapy burner type of diffuser, or from other devices.

The only possible chemical modifications arise from the formation of artefacts, when small amounts of essential oils are evaporated from hot surfaces, or when large amounts of air are bubbled/passed through small volumes of essential oil, or when light of the right wavelength and oxygen combine to chemically modify the evaporated/dispersed (airborne) molecules of the essential oils.

Whether the mode of application (nebuliser oil mists versus essential oils evaporated in the air from a diffuser) affects therapeutic efficacy is a more complicated matter, but for our purposes, and in spite of the hype you might find on websites offering aromatherapy nebulizer etc. I'm going to assume it is not of over-riding importance to the aromatherapists' technique. In many instances very low concentrations of aerially dispersed essential oils will produce the intended effect, and you wont actually need an array of expensive designer equipment to give you larger doses in a shorter time.

On aromatherapy history. When and where did it begin? Also, society seems to be rediscovering it. Why did it die out?

NAHA Director Coordinator Shellie Enteen shares the following:

One could say that aromatherapy is as old as man’s relationship to the plant kingdom and so the beginning of aromatherapy is shrouded in the mists of time. No one knows the identity of the first person to recognize the healing properties of plants but detailed recipes using aromatic compounds are given in the Old Testament and well sealed urns filled with aromatic resins have been unearthed in the tombs of Pharaohs.  Extensive therapeutic use of essential oils is recorded in ancient China and India and much of the Middle East. Roman soldiers on campaign had their wounds treated with honey and myrrh. Terra Cotta distillers have recently been found in archaeological digs, but widespread use of distilled essential oils from Europe began after the invention of glass distillation mechanisms in the 16th century and this opened the door to extracting the volatile components from Chamomile, Lavender and Rosemary and other plants found mainly in the northern regions. 

Certainly before the late 1800’s, the essential oils themselves were harder to get and more highly prized than they are today. The increase in trade routes and conquest in war brought many of the essences and in some cases the plants themselves to new homes in new countries.  A prime example is the oil of Frankincense (Boswellia carteri). Called Olibanum in the East and used in spiritual ritual, it was brought to Europe during the Crusades and given the current common name which means “the true incense.”  Orange trees and other citrus are thought to originate in China and the East, brought back to Spain and Italy by explorers.

The popular use of essential oils and herbs for therapeutic purposes became eclipsed by the development of the microscope and the ability to isolate certain bioactive compounds and reproduce them synthetically.  The most common example is the herb White Willow Bark; replaced by the synthetic form of this plant’s pain relieving compound, salicylic acid, which we know as aspirin.  Synthesized compounds may be greater in strength than naturally occurring plant material and there is no need to rely on growing seasons and other issues that affect crops.  Whether this is a total improvement is debatable. 

Modern interest is credited to the famous story of French chemist Rene-Maurice Gattefosse and his miraculous cure after burning himself in his cosmetics lab in the early 1900’s. In fact, he coined that term ‘Aroma-therapie’ in 1937 and produced a Materia Medica of the therapeutic uses of the aromatic extracts.
  
 For those interested, here is a link about the history of glass.http://inventors.about.com/od/gstartinventions/a/glass.htm