Much research has been published on the anti-tumorial & anti-cancer effects of essential oils. The research seems to have focused on a few oils with long histories of medicinal use: Frankincense, Myrrh and Lemongrass are examples.

In a study just released in the Journal of Chemico-biological Interactions, researchers at the Amercian University of Beirut focused on a specific natural constituent of many common essential oils: Linalool. Linalool is the 'sweetness' of many oils; Lavender is perhaps the most popular linalool-containing oil, though it is found in many, many species of plants. One of the chemotypes of Thyme essential oil is called c.t. (for 'chemotype) linalool, meaning this particular variety of thyme has a high percentage of the linalool molecule.

In this study, linalool derived from steam distilled Coriander essential oil was found to decrease the viability of the HepG2 cell line, cells of liver cancer used throughout the world for cancer research. Coriander was chosen as the spice is considered to have important medicinal qualities. Linalool inhibited these liver cancer cells from replicating. A concentration of 0.4 micromole inhibited 50% of the cells from replicating, a concentration of 2 micromol inhibited 100% of the cells from replicating, therby destroying the cancer.

Now we don't claim to be University researchers here, but we did take a bit of chemistry in college. It appears this is an exceptionally small amount of linalool -- 1 mole of Linalool is 154 grams. This appears to be .000154 grams of linalool per liter of solution the cell line was bathed in.

Given that most Lavender species produce an essential oil containing between 30 and 40% linalool, this is astounding. 25 drops of Lavender essential oil delivers in somewhere around .3 grams of linalool. This is easily absorbed when topically applied. Some medical aromatherapists consider Lavender safe to ingest in small amounts as well.
This is the freely available abstract:

Study: Linalool decreases HepG2 viability by inhibiting mitochondrial complexes I and II, increasing reactive oxygen species and decreasing ATP and GSH levels.

Usta J, Kreydiyyeh S, Knio K, Barnabe P, Bou-Moughlabay Y, Dagher S.
Department of Biochemistry, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.

Coriander is used as an appetizer, a common food seasoning in Mediterranean dishes, and a remedy for many ailments. In this study we tested the biochemical effect of its essential oil components, in particular linalool, its main component. The oil extract was prepared by hydro-distillation of coriander seeds. The various components were identified by gas chromatography coupled to mass spectroscopy.

The effect of the various oil components on the viability of different cell lines (HepG2, Caco2, NIH3t3, MCF7 and Hek293) was examined using MTT assay. Linalool was the most potent and HepG2 cells the most sensitive. A 50% and 100% decrease in the viability of HepG2 was obtained at 0.4muM and 2muM linalool, respectively. Whereas none of the other components exerted a significant effect at concentrations lower than 50muM, myrcene and nerolidol, the structural analogues of linalool, were more potent at 100muM than the other components decreasing HepG2 viability to 26%.

The biochemical effect of linalool on mitochondria isolated from HepG2 showed a concentration-dependent inhibition in complexes I and II activities of the respiratory chain, and a time-dependent decrease in ATP level. In addition, a time-dependent decrease in glutathione (GSH) level and in the reduction of nitroblue tetrazolium was obtained, indicating increase in reactive oxygen species (ROS) generation. Pretreatment with the antioxidants: N-acetyl cysteine (2mM), Trolox (100muM) and different flavonoids (50muM) was partially protective against the linalool-induced cell death; the most effective response was that of rutin and apigenin which restored 91% of HepG2 viability.

We hereby report a decrease in cell viability of HepG2 cells by linalool and identify the mitochondria as one possible target for its site of action, inhibiting complexes I and II and decreasing ATP. In addition linalool increased ROS generation and decreased GSH level.

We will be looking into this particular study further, and will report more information when available on The Ananda Apothecary website. In the meantime, we'll keep using essential oils like we had been, happy to graced by the possibility of another profound health effect!

Digging through the research on the National Institutes of Health website, Pub Med (see www.ncbi.nlm.nih.gov/pubmed) can really be fruitful for scientific data on the effects of essential oils. A great many studies have been published over the last ten years validating the use of essential oils in many realms of natural health, from immunity and infectious illness to wound healing and pain relief, to sleep, mood and cognitive effects. Here are a few studies noting measurable changes in brainwaves upon inhalation of aromas.

Now it's not surprising that essential oils elicit changes in brainwaves - really this happens with anything we perceive with our sense organs: touch, sight, hearing, taste OR smell. What's interesting is that the brainwaves are in-fact measurably different depending on the oil inhaled. Further, the brainwave response was also dependent on the time of day and type of action the subjects were performing when inhaling the oils. Some oils seemed appreciated during physical work, some during mental work, some before work and some after.

The first study describes changes in Alpha brainwaves. These waves are associated with a relaxed, steady, perhaps even 'contemplative' state (one website described most of America as 'alpha wave challenged'!) Lavender essential oil produced the most significant, fairly rapid increase in Alpha wave activity.

The second study describes differences between oils which may be considered relaxing, uplifting or mentally stimulating before and after both physical and mental work. Some oils tested produced very statistically significant results: In summary, try Orange before physical work and Cypress after. Try Basil before mental work and Juniper afterward.

Study: Effects of inhalation of essential oils on EEG activity and sensory evaluation.

Masago R, Matsuda T, Kikuchi Y, Miyazaki Y, Iwanaga K, Harada H, Katsuura T. Graduate School of Science and Technology, Chiba University. mryoko@ergo1.ti.chiba-u.ac.jp

The purpose of this study was to investigate EEG changes in subjects directly after inhalation of essential oils, and subsequently, to observe any effect on subjective evaluations. EEG and sensory evaluation were assessed in 13 healthy female subjects in four odor conditions. Four odor conditions (including lavender, chamomile, sandalwood and eugenol) were applied respectively for each subject in the experiment. The results were as follows. 1) Four basic factors were extracted from 22 adjective pairs by factor analysis of the sensory evaluation. The first factor was "comfortable feeling", the second "cheerful feeling", the third "natural feeling" and the fourth "feminine feeling". In the score of the first factor (comfortable feeling), the odors in order of high contribution are lavender, eugenol, chamomile and sandalwood. 2) Alpha 1 (8-10 Hz) of EEG at parietal and posterior temporal regions significantly decreased soon after the onset of inhalation of lavender oil (p < href="http://www.anandaapothecary.com/aromatherapy-essential-oils/chamomile-roman-essential-oil.html">chamomile. The change after inhalation of sandalwood was not significant. These results showed that alpha 1 activity significantly decreased under odor conditions in which subjects felt comfortable, and showed no significant change under odor conditions in which subjects felt uncomfortable. These results suggest a possible correlation between alpha 1 activity and subjective evaluation.

Study: Alteration of perceived fragrance of essential oils in relation to type of work: a simple screening test for efficacy of aroma.

Sugawara Y, Hino Y, Kawasaki M, Hara C, Tamura K, Sugimoto N, Yamanishi Y, Miyauchi M, Masujima T, Aoki T. Department of Health Science, Hiroshima Prefectural Women's University, Japan.

The perceptional change of fragrance of essential oils is described in relation to type of work, i.e. mental work, physical work and hearing environmental (natural) sounds. The essential oils examined in this study were ylang ylang, orange, geranium, cypress, bergamot, spearmint and juniper. In evaluating change in perception of a given aroma, a sensory test was employed in which the perception of fragrance was assessed by 13 contrasting pairs of adjectives. Scores were recorded after inhaling a fragrance before and after each type of work, and the statistical significance of the change of score for 13 impression descriptors was examined by Student's t-test for each type of work. It was confirmed that inhalation of essential oil caused a different subjective perception of fragrance depending on the type of work. For example, inhalation of cypress after physical work produced a much more favorable impression than before work, in contrast to orange, which produced an unfavorable impression after physical work when compared with that before work. For mental work, inhalation of juniper seemed to create a favorable impression after work, whereas geranium and orange both produced an unfavorable impression then. From these studies, together with those conducted previously with lavender, rosemary, linalool, peppermint, marjoram, cardamom, sandalwood, basil and lime, we thus concluded that the sensory test described here might serve not only as a screening test for efficacy of aroma but also as a categorized table for aroma samples which can act as a reference to each other.

Interest is growing regarding the immune-supportive effects of essential oils, and particularly their antiviral actions. The world's leading aroma-medicine practitioners consider protection from infectious diseases one of aromatherapy's most effective applications.

Many essential oils have demonstrated anti-viral effects, through multiple pathways: By preventing virus replication, through improving the efficiency of our white blood cells, and by changing electrical potential of our cell walls. Many folks have turned to Oregano essential oil as a disinfectant. While this is a potent, broad-spectrum antimicrobial, there may be better choices that are both more gentle and more precise.

Monoterpine alcohols are noted to be the most beneficial and safest of all essential oil components, with strong antiviral effects. Thyme c.t. linalool is our favorite with this naturally constituent for immune support. Hyssop is an important oil due the great diversity in its molecular makeup. Battaglia notes in The Complete Guide to Aromatherapy that Hyssop decumbens is "reputed to have potent antiviral effects" with particular affinity for the respiratory system and diffuser use.

Other highly-regarded oils used for influenza and other viruses that may compromise the respiratory system are Ravensara, Eucalyptus Radiata and Rosemary c.t. Verbenone. These oils can be diffused for gentle exposure to their immune-supportive effects; they can also be applied regularly to lymph nodes. Niaouli is considered a potent immune system stimulant when used in this way.

After a warm shower when the pores are open is an excellent time to do this. Be especially careful for sensitive skin areas ~ diluting your essential oils in a carrier will help them absorb and make the essential oils even easier on your skin.

The lavender plant, endemic to the Mediterranean, has long been cherished for its scent, therapeutic qualities and cooking uses. Essential oil of lavender is referred to as the "mother" of aromatherapy oils by essential oils teacher Salvatore Battaglia. Lavender's flowery, yet gentle, scent is subtle and supportive. Unlike rose or jasmine flower essential oils, lavender's aroma is not overbearing but instead buoys the spirit and assists in the rebalancing of physical and mental bearings. These reasons make lavender an excellent plant for overcoming symptoms of stress.

The term lavender is derived from its Latin root levare, which means "to wash," because of its time-honored use as a bathing herb. French cooking has long incorporated lavender flowers in its bountiful cuisine, primarily in the medley herbes de Provence. The flowers also provide a unique pollen source for local bees, resulting in widely-sought lavender honey. This simple evergreen has also developed a name for itself globally as an indispensable medicinal aid in a variety of therapies. True lavender, and its relatives lavandin, maritime lavender and spike lavender, are now grown in countries ranging from Japan to Russia to Italy.

Lavender is, by far, the most widely used and multifaceted of the common essential oils. Culling essential oil of lavender involves extracting lavendulol and ester lavendulyl acetate from the plant's delicate violet flowers. Whether cultivated at high altitudes or gathered in lowland meadows, true lavender is the most aromatic and powerful of the species and can be used with great effect in all essential oil applications. The plant's energetic qualities of balancing the nervous system make it a powerful oil for soothing nervous exhaustion, and its ability to cool the body enables lavender to combat fiery emotions, such as frustration and agitation.

Lavender's versatility has long been acknowledged by aromatherapists and naturopaths, but current scientific research is verifying lavender's ability work as an axiolytic, or anxiety-combatant plant. A recent study, published by the University of Central Lancashire, employed lavender as an anxiolytic therapy during a test conducted on participants watching an anxiety-provoking film clip. Lavender was taken orally in 100 or 200 microl doses. Researchers found lavender was responsible for reducing symptoms of anxiety in both male and female test subjects. Women were especially affected by lavender in 200 microl doses. Female heart rates were more controlled, and men elicited positive electrodermal response readings. Scientists concluded that decreased stress responses due to lavender indicate the plant is efficacious in dealing with low-stress stimulation.

"High stress" can certainly be an individual definition, yet a frequently shared experience of anxiety is waiting for dental or medical work. In a test developed by a medical school in Vienna, one hundred people, ranging in age from 18 to 77 years old, were given lavender aroma before a dental procedure. The resulting changes in anxiety symptoms suggest lavender can be a powerful, natural anxiolytic during times of worry over personal safety. The Kumugaya Geka Hospital in Japan conducted its own study on lavender in relation to patients preparing for gastroscopy. Researches established what they felt was an ideally calming atmosphere, including giving patients their own essential oil diffuser for use prior to and during the gastroscopy. Those patients using lavender elicited decreased anxiety levels, especially lowered blood pressure, again confirming this plant's ability to work in higher stress situations.

Recovering from medical procedures can also be extremely mentally and physically grueling. In order to test lavender's ability to combat post-procedural stress and recovery, NYU Medical Center implemented a test on twenty-five women receiving breast biopsies. Subjects were given aroma of lavender in their oxygen supply during post-procedural recovery. A promising relationship was noted between how satisfied patients were with their pain recovery and the use of lavender aromatherapy. This is significant, as control group subjects seemed to experience more discontentment with pain management post-surgery. A second study, at the same university, sought to determine whether lavender could be an effective pain management tool in laparoscopic adjustable gastric banding. Traditionally, opioids and NSAIDs (non-steroidal anti-inflammatory drugs) are administered to combat post-operative pain. In this study, lavender was used in conjunction with these medications to again test its efficacy as a pain-management tool. Researchers found lavender aroma lowered patient's dependence on traditional medicines, offering hope that this plant could be used with other medical procedures.

The central nervous system, both the parasympathetic and sympathetic systems, respond powerfully to lavender's soothing qualities. Because it affects the entire nervous system, lavender is capable of alleviating symptoms of stress ? raised heart rate, frustration, worry ? without interfering with our capability to deal with stressors that require immediate action. Anxiety and stress often find their sources in situations which are not always related to actual threats or emotional turmoil, but are instead simply turnings of the mind in response to feelings or helplessness or heightened expectations or fears. Discovering ways of calming stress responses is imperative for creating harmony in the body and mind. Lavender penetrates the central nervous system, making it a perfect plant for working with daily stress and also for pacifying our nerves at the end of a long day, when we so dearly need our sleep.

Lavender oil is easily combined with a variety of carrier oils for massage application, to create compresses, for dermatological use and as a salve or balm. As its Latin root implies, it is excellent when used in bathing, and it can also be used with youngsters. It creates a heavenly mood when used in a vaporizer or diffuser in your home, office or car, and won't likely offend others with its gentle scent. Lavender buds can also be tossed into gourmet cooking and add an intriguing aroma to herbal decoctions. And don't forget those delightful flax and lavender eye pillows ? if insomnia plagues your nights, lavender is your best ally. For daytime stress, keeping a bottle of lavender essential oil in your car or bag can neutralize a wide variety of symptoms that keep you from functioning at your best. Just stop, breathe deep and let this beautiful oil show you how to regain your footing once more.

Scientific research regarding health and medical applications of essential oils is going on regularly at universities and other facilities around the world. Many of these studies are immediately applicable to aromatherapy practitioners for improved health and well-being, while others spark interest in the potential of essential oils as a part of future medicine protocols. Modern scientific research is regularly confirming aromatherapy's practical medical applications! Here's a look at two important journal publications just released about direct effects of essential oils in the brain, reviewed by the staff at Ananda Aromatherapy of Boulder, Colorado.

These two are really interesting studies, as inhalation of many essential oils have been considered sharpening to our mental capacities. These have been thought to be more esoteric effects of aromatherapy, like the aroma just makes us feel good so we are a little more mentally clear. Now some of the biochemical mechanisms of these effects are being elucidated, proving it's not just all in our minds! Rosemary and Lemon are two very common, inexpensive oils researched for their ability to directly impact test scores of university students (in Japan at least), and reduce errors made by office workers (also in Japan -- thankfully, Japanese scientists are into aromatherapy). These oils are readily available, inexpensive, safe, and can be used in nebulizing diffusers (which output therapeutic concentrations of essential oil vapor).

In the first study, perfomed at the Institute for Environmental Sciences at the University of Shizuoka Japan, Tarragon, Inula, Lavender and Holy Basil were tested for their ability to inhibit acetylcholinesterase (AChE) activity. In other words, their ability to prevent the breakdown of acetylcholine, the primary information-handling neurotransmitter. Supplements with this action are becoming more and more popular with regular folks trying to increase their smarts, and are used to treat dementia (Alzheimer's) by increasing the amount of acetylcholine in the brain.

Of the essential oils tested, Tarragon (Artemisia dracunculus) produced in France had the highest inhibition of acetylcholinesterase, though all the oils tested showed significant AChE inhibitory activity. All the oils were analyzed by GC/MS to find the individual natural chemical constituents of the oils which produced this effect. Of real interest is that 1,8-Cineol had the greatest inhibitory activity of all the constituents examined. Why this this interesting? Rosemary essential oil has long been considered a mental stimulant (we find in the office to be particularly brightening) and has been studied for this effect, improving mental focus in humans through a variety of tests. The primary component of Rosemary essential oil is 1,8-Cineol (it is also a major constituent of Eucalyptus oils, used for invigorating massages and steam treatments).

Also of great interest was that the effect of these constituents relative to their amounts in the complete natural essential oil was not very high -- meaning the complete essential oil, with nature's balance of the chemical constituents, was synergistically more effective than the singly-extracted molecules. This is a theme in aromatherapy: that the complete natural essential oil will generally have more benefits than a single 'active ingredient' extracted in a laboratory -- Therapeutic grade oils are those that retain the natural balance of the plant's, with proper harvesting and distillation methods.

While a single chemical from an essential oil may show a specific effect in a biochemical pathway, these molecules don't smell very interesting. A really fine, wildcrafted Rosemary essential oil is a pleasure to breathe in. Other studies have shown stress reduction (along with mental stimulation) occurs when Rosemary is inhaled, and it's well known that our brains perform more accurately when not under stress. The bottom line is that while it's a regular practice for researchers to examine single components of a natural substance to find the 'active ingredient', in general in natural medicine, and in particular with aromatherapy, the whole natural extract will be better for our health.

The second study very much ties in with the first, as it demonstrates the ability of Lemon essential oil to directly prevent dementia (Alzheimer's). The causes of dementia are not well understood, though some pathways are clearly documented. Toxicity from certain chemicals may lead to a breakdown in neurotransmitter systems, resulting in dementia symptoms. In research performed at the Laboratory of Nutritional Biochemistry in Shizouka, Japan, Lemon essential oil was shown to inhibit memory impairment from scopolamine exposure, preventing dementia. AND, as a final note of the study, the combined primary constituents of Lemon essential oil were shown to inhibit acetylcholinesterase activity! Lemon essential oil both prevents dementia and increases acetylcholine stores in the the brain.

How can you benefit from these studies? The best method is to find a cold-air nebulizing diffuser. These employ no water or other carrier, and make a very fine mist of essential oils that easily evaporate into your room. These are the only diffusers that create high concentrations of essential oils in the air -- enough to show measurable biochemical effects. A 'warming' diffuser or other non-nebulizing style will allow you to smell the aroma, though the concentration will be significantly lower. At Ananda Aromatherapy we've been trying Lemon and Rosemary together, along with a little sweeter oil like cold-pressed Orange, Tangerine or Mandarin. Lavender or Ylang Ylang might go well with this too, for a calming effect at the same time. One can set the diffuser up on a timer so it runs ten minutes every hour and run it all during the day. The oils can always be changed to other 'brightening' aromas, as they will likely have similar effects -- getting the mind sharp and staying sharp!

Simple Lemon essential oil is often overlooked for it's aroma-therapeutic effects, mostly as it's not very exotic. Lemon..."ho-hum, I've got lemons in the 'fridge"...but the idea of Frankincense or Helichrysum sounds like it might do us more good ~ in a mysterious sort of way. But all essential oils have their use, and lemon is at the front of the pack in terms of supporting mental and emotional health.

Lemon essential oil has long been used as a mental stimulant and brightener of the mind. Now scientific investigators have demonstrated some of the mechanisms for this effect. In Japan, a study has shown that lemon oil vapor (as produced by a nebulizing diffuser) has anti-stress effects by modulating both the Serotonin and Dopamine neurotransmitter systems. The conclusion was that lemon oil aroma has both anti-anxiety and anti-depressant effects. Other research performed in Japan years ago showed a significant improvement in mental accuracy for office workers inhaling the aroma.

Also recently published by other Japanese researchers shows that lemon oil actually limits the toxicity of scopolamine ~ a natural plant alkaloid with medicinal effects at low dosages, that shows neurotoxicity at higher dosages. Scoploamine overdose can cause dementia and memory loss. Lemon oil prevented these effects from occuring.

Lemon oil is easy to use, and very safe. It's aroma can be enjoyed from any diffuser, though it would be best to use in a cold-air unit due to the delicate nature of citrus essential oils in general. One can simply just enjoy the aroma as frequently as you like. Here are the studies:

Study: Components of lemon essential oil attenuate dementia induced by scopolamine.

Zhou W, Fukumoto S, Yokogoshi H.Laboratory of Nutritional Biochemistry and G-COE Program in the 21st Century, Graduate School of Nutritional and Environmental Science, University of Shizuoka, Shizuoka, Japan.

The anti-dementia effects of s-limonene and s-perillyl alcohol were observed using the passive avoidance test (PA) and the open field habituation test (OFH). These lemon essential oils showed strong ability to improve memory impaired by scopolamine; however, s-perillyl alcohol relieved the deficit of associative memory in PA only, and did not improve non-associative memory significantly in OFH. Analysis of neurotransmitter concentration in some brain regions on the test day showed that dopamine concentration of the vehicle/scopolamine group was significantly lower than that of the vehicle/vehicle group, but this phenomenon was reversed when s-limonene or s-perillyl alcohol were administered before the injection of scopolamine. Simultaneously, we found that these two lemon essential oil components could inhibit acetylcholinesterase activity in vitro using the Ellman method.

Study: Lemon oil vapor causes an anti-stress effect via modulating the 5-HT and DA activities in mice.

Komiya M, Takeuchi T, Harada E.Graduate School of Veterinary Science, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan.

We examined the anti-stress action of the essential oils of lavender, rose, and lemon using an elevated plus-maze task (EPM), a forced swimming task (FST), and an open field task (OFT) in mice. Lemon oil had the strongest anti-stress effect in all three behavioral tasks. We further investigated a regulatory mechanism of the lemon oil by pre-treatments with agonists or antagonists to benzodiazepine, 5-HT, DA, and adrenaline receptors by the EPM and the FST. The anti-stress effect of lemon oil was significantly blocked by pre-treatment with frumazenil, benzodiazepine receptor antagonist, or apomorphine, a nonselective DA receptor agonist. In contrast, agonists or antagonists to the 5-HT receptor and the alpha-2 adrenaline receptor did not affect the anti-stress effect of lemon oil. Buspirone, DOI, and mianserine blocked the antidepressant-like effect of lemon oil in the FST, but WAY100,635 did not. These findings suggest that the antidepressant-like effect of lemon oil is closely related with the 5-HTnergic pathway, especially via 5-HT(1A) receptor. Moreover, the lemon oil significantly accelerated the metabolic turnover of DA in the hippocampus and of 5-HT in the prefrontal cortex and striatum. These results suggest that lemon oil possesses anxiolytic, antidepressant-like effects via the suppression of DA activity related to enhanced 5-HTnergic neurons.