December 12, 2011

Lavender oil and negative innuendo

by Robert Tisserand

In a recent blog post an Environmental Working Group (EWG) research assistant suggests that lavender oil may be unsafe, saying: “the science is still evolving and safety can’t be assumed.” The science is still evolving? Isn’t that true of anything? Are we just sowing the seeds of doubt here?

I have written a number of posts about the EWG and sloppy science. Their modus operandi involves highlighting negative information, along with liberal use of the phrase “has been linked to”. Facts are so often distorted that their reputation in scientific circles is all but worthless. I have never read an EWG report in which both sides of an argument are presented. The problem I have with this approach is that the EWG audience is consumers, who have neither the scientific training nor the knowledge and expertise to challenge what is being said. In spite of this many do, because they instinctively feel that something is not right.

Skin allergy
Lavender oil “has been linked to” allergic reactions, it’s true. But how strong is that link? After all, if you look hard enough, you will find at least one allergic reaction report for almost every substance used in cosmetics. Cherry picking a few negative studies is not a useful way to help consumers assess product safety. What we need is a comparative rating that clearly flags high-risk ingredients, along with practical safety guidelines.

“Allergy epidemics” have occurred in the past, most often with preservatives. As use becomes more extensive, adverse reactions escalate, and eventually the substance is either banned or restricted. In spite of widespread use, this is not happening with lavender, which has been the most popular essential oil for aromatherapy use since the 1970s.

The EWG post is written by Swati Sharma. She tells us that: “Despite its ubiquity in cosmetics, researchers in Japan who compared eight essential oils found that lavender caused the greatest number of skin allergies.” No it did not, unless you only look at two of the nine years of the study! The Japanese researchers tested six essential oils, one absolute and two essential oil constituents. The essential oil that produced the most adverse reactions was ylang-ylang (tested at 5%), followed by geranium (tested at 20%) followed by lavender (also tested at 20%). And since all the other substances were tested at either 5% or 2%, the relative risk of each cannot be compared anyway. The higher the test concentration, the greater will be the number of reactions. And, the Japanese subjects were all dermatology patients “suspected of cosmetic dermatitis”, an especially high-risk group.

Considering that the lavender oil was patch tested at 20% in a high-risk population, and that only 1.4% (21 of 1,483) of patients had an adverse reaction, this does not suggest a significant allergen. Other research points to lavender oil presenting a very low risk. When 50 healthy volunteers were patch tested with the undiluted oil, there were no reactions (Meneghini et al 1971). Similarly, none were produced in 25 volunteers tested with lavender at 10% (Opdyke 1976 p451). In a study of 200 dermatitis patients in Poland, none were sensitive to 2% lavender oil (Rudzki et al 1976). In a Danish study, two of 217 dermatitis patients (0.9%) tested positive to 2% lavender oil (Veien et al 2004). Tested at 1%, lavender oil produced no reactions in 273 dermatitis patients (Meneghini et al 1971).

Taken together, these results show that two of 690 dermatitis patients (0.3%) reacted to lavender oil when patch tested at 1% or 2%. However, extrapolating from patch test data on dermatology patients to the general population is notoriously difficult (especially since the conditions of patch testing exaggerate risk) and the actual number of people with adverse reactions to lavender is very much less than 0.3%. Over a 15 year period (1986-2000) there have only been five cases of lavender oil allergy reported worldwide (Brandão 1986, De Groot 1996, Keane et al 2000, Schaller & Korting 1995, Selvaag et al 1995) and three were people with multiple allergies. This is in contrast to millions of bottles of undiluted lavender oil being sold to consumers per annum, and millions more personal care products containing lavender oil.

From all of the above we can conclude that a 20% concentration of lavender oil might be risky for Japanese consumers with cosmetic allergies, but 2% is not a risk to anyone, and even undiluted lavender is safe to use on healthy skin. Not only is lavender a very low-risk skin allergen, it possesses anti-allergic properties. Topically applied, the oil inhibited immediate-type allergic reactions by inhibiting the release of histamine from mast cells (Kim et al 1999). How is this possible? Probably because in most cases, allergies only occur from the use of oxidized lavender oil. The unoxidized oil is anti-allergic, and is even moderately antioxidant (Wei and Shibamoto 2007).

Oxidation
Sharma tells us that linalyl acetate, a major constituent of lavender oil, can oxidize in the presence of atmospheric oxygen, “forming allergens that can cause contact dermatitis” (Sköld et al 2008). Indeed it can, as can linalool, the other major constituent of lavender oil (Sköld et al 2004). However, these are theoretical risks, not actual risks, and lavender oil oxidation is a process that takes many months, even years. What this research suggests is that products containing lavender oil should be protected from oxidation by the addition of antioxidants, and that very old products should be discarded. The International Fragrance Association (IFRA) does not have a regulation for lavender oil, but it does for linalool. Referring to linalool-rich essential oils, the IFRA guideline recommends the addition of an antioxidant: “The addition of 0.1% BHT or a-tocopherol has shown great efficiency” (IFRA 2009).

Next, Sharma informs us that “lavender oil may be toxic to human skin cells” though curiously no reference is given (it’s Prashar et al 2004). I addressed this issue in a previous post about lavender, in which I explain how we know that the oil is not a skin irritant, and is not toxic to skin cells when applied to human skin.

Hormone disruption
Finally, Sharma raises the question of lavender oil and hormone disruption, an issue I have also addressed previously, in this article. To sum up, there was no established link between lavender oil and breast growth in three pre-perbertal boys, but lavender oil did show a weak in vitro estrogenic action in two (of the four possible) types of in vitro test for estrogenic activity (Henley et al 2007). None of this establishes that lavender oil disrupts hormones. To quote Diel et al (1999): “…even a combined use of several in vitro test systems is not able to predict the occurring action of a substance in the organism.” In other research, lavender oil was significantly toxic to human breast cancer cells (Zu et al 2010) suggesting that it would prevent breast cancer, and not increase risk.

Summary points
Consumer products containing lavender oil may benefit from the addition of an antioxidant, such as alpha-tocopherol. This should be used at 0.1-0.2% (note that using more is not more effective).

Bottles of lavender oil, or products containing lavender oil, that are more than 12 months old (after first use) should be discarded if they no longer smell fresh.

There is a theoretical risk of skin allergy from lavender oil, but this risk is extremely low. Restricting the percentage of lavender oil in leave-on products (skin creams, lotions, gels) to 2% would be over-cautious, but combined with the addition of an antioxidant, will make a product super-safe.

Lavender oil has a weak in vitro estrogenic activity, but there is no reason to believe that this translates to a hormone-disrupting effect in humans.

References
Brandão FM 1986 Occupational allergy to lavender oil. Contact Dermatitis 15:249-250

De Groot AC 1996 Airborne allergic contact dermatitis from tea tree oil. Contact Dermatitis 35:304-305

Diel P, Smolnikar K, Michna H 1999 In vitro test systems for the evaluation of the estrogenic activity of natural products. Planta Medica 65:197-203

Keane FM, Smith HR, White IR et al 2000 Occupational allergic contact dermatitis in two aromatherapists. Contact Dermatitis 43:49-51

Henley DV, Lipson N, Korach KS et al 2007 Prebubertal gynecomastia linked to
lavender and tea tree oils. New England Journal of Medicine 365: 479-485

IFRA 2009 Standards, including amendments as of October 14th 2009. International Fragrance Association, Brussels. http://www.ifraorg.org

Kim HM, Cho SH 1999 Lavender oil inhibits immediate-type allergic reaction in mice and rats. Journal of Pharmacy & Pharmacology 51:221-226

Meneghini CL, Rantuccio F, Lomuto M 1971 Additives, vehicles and active drugs of topical medicaments as causes of delayed-type allergic dermatitis. Dermatologica 143:137-147

Opdyke DL 1976 Monographs on fragrance raw materials. Food & Cosmetics Toxicology 14 supplement

Prashar A, Locke IC, Evans CS 2004 Cytotoxicity of lavender oil and its major components to human skin cells. Cell Proliferation 37:221-229

Rudzki E, Grzywa Z, Brud WS 1976 Sensitivity to 35 essential oils. Contact Dermatitis 2:196-200

Schaller M, Korting HC 1995 Allergic airborne contact dermatitis from essential oils used in aromatherapy. Clinical & Experimental Dermatology 20:143-145

Selvaag E, Holm JO, Thune P 1995 Allergic contact dermatitis in an aromatherapist with multiple sensitizations to essential oils. Contact Dermatitis 33:354-355

Sköld M, Börje A, Harambasic E et al 2004 Contact allergens formed on air exposure of linalool. Identification and quantification of primary and secondary oxidation products and the effect on skin sensitization. Chemical Research in Toxicology 17:1697-1705

Sköld M, Hagvall L, Karlberg AT et al 2008 Autoxidation of linalyl acetate, the main component of lavender oil, creates potent contact allergens. Contact Dermatitis 58:9-14

Sugiura M, Hayakawa R, Kato Y et al 2000 Results of patch testing with lavender oil in Japan. Contact Dermatitis 43:157-160

Veien NK, Rosner K, Skovgaard GL 2004 Is tea tree oil an important contact allergen? Contact Dermatitis 50:378-379

Wei A, Shibamoto T 2007 Antioxidant activities and volatile constituents of various essential oils. Journal of Agricultural & Food Chemistry 55:1737-1742

Zu Y, Yu H, Liang L et al 2010 Activities of ten essential oils towards Propionibacterium acnes and PC-3, A-549 and MCF-7 cancer cells. Molecules 15:3200-3210

Robert Tisserand is internationally recognized for his pioneering work in many aspects of aromatherapy since 1969 and frequent contributor to the aromaconnection blog.

Posted by Blogmistress on December 12, 2011 in Aromatherapy, Cosmetics, Lavender/Tea Tree/Gynecomastia, Safety/Toxicity, Science | Permalink | Comments (1) | TrackBack

June 22, 2011

Negative Bias

by Robert Tisserand

Safety legislation does not always accord with current knowledge on safety, for the simple reason that new scientific data are always being published. Guidelines are periodically made more stringent, but they are almost never loosened, even when new information suggests it. Regulators don’t like to admit that they were wrong, and this is especially true of the European Union. In the United States, although the FDA has few regulations that directly restrict cosmetic ingredients, most manufacturers, especially the larger ones, follow both IFRA guidelines and EU regulations. Taken together, these result in some extremely stringent measures for essential oils.

The reason that US manufacturers follow EU guidelines is because, if they sell internationally, they use one formulation that works in all regions – multiple formulations are uneconomic. And, although IFRA guidelines are technically a voluntary code, they are very widely adhered to for two reasons. One, almost all

Coriandrum sativum

large cosmetics manufacturers are full members of IFRA, and as such they formally agree to follow the IFRA code. Two, even non-members want to be sure they are manufacturing safe products, plus they don’t want to risk the possible legal ramifications of not adhering to industry best-practice guidelines. IFRA recently put out a video called Making Scents, which you can find here.

In spite of all this, some North American consumer groups are concerned that many personal care products contain ingredients that are highly toxic, and that are banned in Europe. There are particular concerns about fragrances, which are said to contain chemicals that are hormone disrupting, neurotoxic, teratogenic or

Coriandrum sativum

carcinogenic. The fact that fragrance ingredients are not declared on labels feeds the perception of hidden toxins lurking. However, these concerns are often misplaced. For example, fears of neurotoxicity may be inappropriately based on the results of toxicity testing, in which the signs and symptoms of a fatal dose are noted. And, concerns about skin allergy are sometimes based on results that, when closely examined, do not represent a significant risk for consumer products.

There is a growing hysteria about “chemicals” in consumer products, as if the fact of a substance being a chemical made it inherently toxic. It is understandable that consumers do not know the difference between a synthetic chemical and a naturally-occurring one. (Synthetic chemicals, while not necessarily more toxic, are less environmentally friendly.) However, even the Environmental Working Group appears not to know which essential oils contain which chemical constituents.

The European Union “allergens”
In 2003, the European Union’s Scientific Committee on Cosmetic Products and Non-Food Products (SCCNFP) published a directive listing 26 fragrance materials as skin allergens (SCCNFP 1999). One of the criteria listed was that “Positive patch test data from more than one patient in more than one independent centre should be present.” In other words, a substance could be listed as an allergen if there were two or more reports of skin allergy. Even if these two reports occurred over, say, 20 years. Several papers have since been published strongly suggesting that many of the 26 fragrance materials should not be listed as allergens at all. The EU has done nothing but dig its heels in.

Linalool is one of the EU “allergens”. If present in a cosmetic product at over 100 ppm (0.01%) in a wash-off product or 10 ppm (0.001%) in a leave-on product, linalool must be declared on the ingredient list if sold in an EU member state. Doesn’t sound too bad, does it? The problem is, neither manufacturers nor retailers want to get sued, or branded as selling unsafe products, and most retailers will only carry cosmetics that have passed an independent safety assessment, which is almost entirely based on looking at the levels of “allergens”. So the de facto result is that very few manufacturers take the risk of having a “known allergen” in a product at over the declarable amount.

Linalool is a major constituent of some commonly-used essential oils and is found in approximately 200 other essential oils. But linalool is not a high-risk allergen. In fact, it’s superlatively safe on the skin. Between 1969 and 2007 (38 years), a total of thirteen dermatitis patients out of the 25,164 tested, (0.05%) were allergic to linalool when patch tested, and less than this actually had allergic reactions to products containing linalool (De Groot 1987, De Groot et al 2000, Fregert and Hjorth 1969, Frosch et al 1995, Itoh et al 1986, Santucci et al 1987, Schnuch et al 2007). Yes, 0.05% is more than zero, but it’s pretty close to the 0.03% reaction rate for petrolatum, the least dermally allergenic substance known to mankind. One way of looking at this is that adding linalool to a product increases risk by about 0.02%. That’s probably less than almost any other known cosmetic ingredient.

Linalool table

But, this assumes that patch testing reflects real-world risk, which it does not, in fact it is designed to exaggerate risk. It does this in two ways. One, patches are non-permeable, and are left adhered to the skin for 48 hours. Two, the concentrations used in testing are higher than those encountered in personal care products. Linalool is tested at a 5%, 10% or 20% dilution. Since skin allergies are dilution-dependent, lower dilution will carry less risk. There is no dermatological or other scientific rationale that suggests extrapolating data from a 10% dilution to a safety threshold of 0.001% – 10,000 times less! Quite the opposite – the clinical data suggest that a 10% concentration of linalool in cosmetics is virtually non-allergenic. When tested at 5% on a total of 1,399 dermatology patients, linalool produced not one single allergic reaction (Frosch et al 1995, Itoh et al 1986, Santucci et al 1987).

The EU listed linalool as an allergen because – according to their own report – five dermatitis patients had allergic reactions to it over a five-year period on patch testing. Considering that linalool is (or at least used to be) one of the most commonly-used fragrance materials, an average of one reported adverse reaction per year, on planet earth, is about a negligible as it is possible to get. But, this still does not represent actual risk to consumers, which is likely much lower.

Data from Schnuch et al 2007

Data from Schnuch et al 2007

Of the 26 EU “allergens”, 16 are essential oil constituents and two are absolutes. In 2007, these were each tested on groups of 2,000 or more dermatology patients. Of the 16, six produced so few adverse reactions that the report concluded that they should not be classed as allergens at all. Benzyl benzoate, for example, produced not a single adverse reaction in 2,003 patients (Schnuch et al 2007). The other non-allergenic constituents are linalool, limonene, benzyl alcohol, benzyl salicylate and anisyl alcohol, and other dermatologists have questioned the classification of linalool and anisyl alcohol as allergens (Gilpin and Maibach 2010, Hostýnek and Maibach 2003a). Other research has shown that adverse reactions to coumarin are due to impurities present in the synthetic coumarin used for testing, and that 99% pure coumarin is not allergenic (Vocanson et al 2006, 2007). And, Hostýnek and Maibach (2003b) argue that the evidence for farnesol being an allergen is highly debatable. If we add farnesol and coumarin to the list of spurious allergens, then 50% of the EU 16 are a mistake.

These voices of dissent are not insignificant, and include some of the most distinguished dermatologists in the world. They question whether the patch test information is “clinically relevant”, and whether it can be extrapolated to estimate risk in the general population. Certainly, the percentages in the Table above under “% of patients reacting” do not represent real-world risk, and for many of these substances there is not a single case of skin reaction that has been proven to be caused by the substance in question. What these numbers do suggest is the relative potency between the different substances. Or at least, it would if they had all been tested at the same % concentration. And just to be clear, the division into three groups by Schnuch et al is theirs, not mine.

The David Suzuki Foundation
Paradoxically, EU cosmetics legislation is frequently cited in North America as an example of what cosmetics legislation should look like. In Canada for example, the David Suzuki Foundation (DSF), an environmental activist group, has this message for their supporters: “Consumers have the right to know about all ingredients contained in cosmetics – including fragrance chemicals. European regulations are stronger. They require 26 sensitizers used as cosmetic fragrances to be identified on the label. That’s a start, and it’s better than what we have in Canada.”

The DSF says that their mission is “to protect the diversity of nature” but the European legislation unfairly targets the farmers that grow the plants that produce the essential oils that contain the chemicals that David Suzuki wants to see identified on labels, a move which will inevitably lead to further restriction. I am not opposed to the principal of ingredient declaration for fragrances, and I applaud those manufacturers that have already made this move. However, I believe that if a product contains lavender oil, this should be declared as “lavender oil”, and the 70 or so constituents of lavender oil should not have to be listed. I have already argued here against the idea that constituents of ingredients should be declared on cosmetic labels.

The Environmental Working Group
The Environmental Working Group (EWG) is a US-based organization that calls even more stridently for increased legislation of fragrance ingredients. Fragrances, we are told, contain chemicals that are neurotoxic, teratogenic, carcinogenic and hormone disrupting.

Lemon 500x332On its Skin Deep database, the EWG bases hazard ratings of essential oil constituents largely on the flawed EU legislation. The EWG makes no reference to the dissenting voices in the scientific community, either because it is unaware of such dissent, or because it chooses to ignore it. The EWG is not a regulatory body, nor does it publish safety guidelines, it simply labels a cosmetic ingredient with a number from 0 to 10, with 10 being the most hazardous. It does give some explanation for how this number is arrived at, but no specific recommendations are made. Skin Deep gives linalool a hazard rating of 4. However, Aniba rosaeodora (Rosewood) oil, which contains 82-90% linalool, has a hazard rating of 0-1. Coriander seed oil, which contains 59-88% linalool, has a hazard rating of 1. These hazard ratings seem to be inconsistent.

Skin Deep, at least, is consistent in its inconsistency. Limonene has a hazard rating of 6, and yet lemon oil (57-76% limonene) has a hazard rating of 0, and sweet orange oil (84-96% limonene) a hazard rating of 1. Safrole (a rodent carcinogen) is given a hazard rating of 7, while sassafras oil (83-90% safrole) is given a hazard rating of 0. Sassafras oil contains more safrole than any other essential oil. Some other carcinogens found in essential oils, asarone and estragole for instance, are not even mentioned on the Skin Deep database. Pulegone is a hepatotoxic compound found in pennyroyal oil. In spite of this, both the compound and the essential oil are rated as 0. Go figure.

Fragrance
If you look at “Fragrance” on the EWG’s Skin Deep database, you will see that it has a rating of 8. This applies to any fragrance at all, and 11,376 products are listed. This seems more like a declaration of war on the personal care products industry than a genuine safety guideline! And note that “fragrance” is rated as far more hazardous than either sassafras oil (a known carcinogen) or pennyroyal oil (a known hepatotoxin). The principal reasons given for the high rating for fragrance are:

Allergies & immunotoxicity
Miscellaneous
Neurotoxicity
Data gaps

It’s worth taking a closer look at the Skin Deep rationale:

Allergies & immunotoxicity
This is further defined as “linked to immunotoxicity, or harm to the immune system, a class of health problems that manifest as allergic reactions or an impaired capacity to fight disease and repair damaged tissues in the body.” Perfume is then cited as a “known human immune system toxicant”, and a single reference is given: SCCNFP 1999. This is the opinion paper that eventually became a legal directive in 2003.

Since this is a 63 page document, there is insufficient space here to dissect it in detail. To pick one simple fact, the document concerns 24 fragrance ingredients that, it is recommended, should be restricted in consumer products because they are potential contact allergens (oakmoss absolute and treemoss absolute were added later). This is to say, 24 of the estimated 3,000 existing fragrance ingredients, or 0.8%. To conclude from this that all fragrances present a high, or even a moderate risk of skin allergy is negative bias, because it is not based on real-world risk.

Returning to the Skin Deep wording, something is amiss. A single reference is given for skin allergy, but no supporting evidence is cited for immunotoxicity, which is a much more serious hazard. This could be viewed as a deliberate manipulation of words and/or facts in order to mislead and suggest negative information that does not exist. Skin allergy is indeed a sub-category of immunotoxicity, but the principal meaning of the word – causing damage to the immune system – does not apply. But, because Skin Deep couches these terms together “Allergy/Immunotoxicity”, and because it has – quite correctly – defined immunotoxicity as damage to the immune system, any substance that can cause skin allergy is also flagged by implication, as reducing your capacity to fight disease, which is something totally different. Since there is no evidence of immunotoxicity, apart from skin allergy, this looks like negative bias again.

Bias-1Miscellaneous
This is defined as “ingredient not fully labeled – identity unknown”. Indeed, fragrance is not a single ingredient, and the great majority of fragranced products do not fully declare their fragrant ingredients. This has been a subject of debate for some time, and is a reasonable criticism in terms of transparency. However, it is not, per se, any kind of risk assessment or toxicity rating, it is simply a fact, an observation.

Neurotoxicity
This is defined as “Linked to neurotoxicity, or harm to the brain and nervous system, a class of health problems that can range from subtle developmental delays to chronic nerve degeneration diseases.” One reference is given, which is said to provide “moderate evidence” of neurotoxicity. The reference is: USHR (U.S. House of Representatives), 1986. Neurotoxins: At Home and the Workplace. Report by the Committee on Science & Technology, Report 99-827. Sept 16 1986. In this report it is claimed that over 95% of chemicals used in fragrances are synthetic compounds derived from petroleum, including benzene derivatives, aldehydes and other toxins and sensitizers capable of causing cancer, birth defects central nervous system disorders and allergic reactions.

The report is not a scientific study, and so what we have is nothing but hearsay. Somebody said/wrote something, so the “has been linked to” is satisfied! All fragrances have now “been linked to” neurotoxicity. This is a very serious charge. Note that the EWG claim is that they “provide additional information on personal care product ingredients from the published scientific literature.” Not always it seems. And note that ALL FRAGRANCE is flagged as being “linked to” neurotoxicity. “Benzene derivatives, aldehydes and other toxins and sensitizers” is, by the way, an interesting choice of words in itself, since it implies that all the benzene derivatives and/or aldehydes used in fragrances are toxic and/or skin sensitizing. This is simply not true.

Data gaps
This is explained as “not assessed for safety in cosmetics by industry panel.” This cryptic statement is odd to say the least. The implication is that no fragrance-related organization has assessed “fragrance” for safety in cosmetics. It seems that Skin Deep are unfamiliar with an organization called IFRA – the International Fragrance Association – that has been assessing fragrance for safety in consumer products for some 40 years. IFRA has many fragrance-related safety standards. That’s pretty much all they do. In my opinion, IFRA standards are often over-reaching and too stringent.  So, what exactly is meant by “Data gaps” for fragrance is, well, anyone’s guess.

At the end of the Skin Deep page on Fragrance is some useful information: “1,452 studies in PubMed science library may include information on the toxicity of this chemical” And then there is a link to PubMed. These are the search criteria: (”FRAGRANCE”[TW] OR “FRAGRANCE”[TW] OR “PARFUM”[TW] ) AND (*toxic* OR cosmet* OR derm* OR irritation OR sensiti* OR “personal care products” OR skin OR gavage OR mutagen* OR carcinogen* OR “biological activity”). Fine, great, useful, practical. What I really don’t get though, is why these 1,452 research papers are listed under the heading “Data gaps”. Isn’t this actually quite a lot of information?

Perhaps the Skin Deep approach is: “if you won’t tell us what’s in your fragrances, then we’re going to assume the worst”. But, since there’s very little evidence that fragrance causes any real harm anyway, assuming the worst involves some academic acrobatics that are shameful and not worthy of scientific credibility. Insinuation, implication and “has been linked to” is not evidence of anything, and the liberal use of this tactic shows negative bias.

Linalool: a narcotic?
A Google search for “Linalool: a narcotic” comes up with 19,200 hits. This is because the following piece of advice about a well-known fabric softener and dryer sheet fragrance is repeated that many times:

* Ethanol: On the EPA’s Hazardous Waste list and can cause central nervous system disorders.
* Limonene: Suspected Gastrointestinal or Liver Toxicant, Immunotoxicant, Kidney Toxicant, Neurotoxicant, Respiratory Toxicant, and Skin or Sense Organ Toxicant.
* A-Terpineol: Can cause respiratory problems, including fatal edema, and central nervous system damage.
* Ethyl Acetate: A narcotic on the EPA’s Hazardous Waste list.
* Camphor: Causes central nervous system disorders.
* Chloroform: Neurotoxic, anesthetic and carcinogenic.
* Linalool: A narcotic that causes central nervous system disorders.

I’m not going to go into the validity of every single claim made here, but I will tell you that most of it is either incorrect or highly misleading. Ethanol for example, known to most of us simply as alcohol, can of course cause CNS disorders if you drink enough of it. But in a dryer sheet? Are you kidding? Some of the sites that include the above information go into more detail on linalool:

LINALOOL Narcotic. Causes CNS disorders. …”respiratory disturbances” …”Attracts bees.” “In animal tests: ataxic gait, reduced spontaneous\motor activity and depression …depressed heart activity …development of respiratory disturbances leading to death.”

Abdominal injectionMediumThis information is entirely derived from LD50 testing of linalool (Jenner et al 1964, Letizia et al 2003). This is the classic test to find the single lethal dose for any substance. Rats and mice are most commonly used, and the dose cited is the one that is lethal to 50% of the animals. When you give a mammal a fatal dose of a substance it is not unusual to see some adverse effects on the nervous system, such as staggering, difficulty breathing etc., nor is it surprising if there are “respiratory disturbances leading to death.” Ataxic (unsteady) gait is probably mentioned in a majority of all LD50 test results. The oral LD50 values for linalool range from 2.2 to 3.9 g/kg, which is equivalent to an average adult human drinking 154 – 270 g (5.4 – 9.5 oz). In one of the studies, a non-fatal dose of linalool had a sedative effect on mice when injected into the abdomen at 178 mg/kg, and impaired muscle co-ordination (Atanassova-Shopova et al 1973). This is equivalent to a human dose of 12.5 mL, or 0.44 oz.

None of this means that your dryer sheets are going to kill you or your family. Nor will they cause you to faint, sway, fall over, lose control of your muscles, or otherwise behave as if drunk or dying. If you have multiple chemical sensitivity you may react adversely to any fragrance material, but not necessarily because that substance is itself inherently toxic. Unless you are in the habit of either drinking linalool by the cupful or injecting half an ounce of it into your abdomen, you may safely ignore these dire warnings, which have absolutely no relevance to the use of linalool in cosmetic or household products.

Conclusions
At least as far as essential oils are concerned, the EWG database reveals a shocking degree of ineptitude. They seem to have no idea which essential oils contain which constituents, and they only know about legal restrictions, which they automatically support 100%. If the EU says that linalool is a skin allergen, then it must be right. The EWG staff don’t seem to have read most of the toxicological literature, which they simply give a PubMed link to, and throw this in under “Data gaps”! They are just tossing out information hoping that some of it will stick. There is no science-based risk assessment, and the hazard ratings don’t tell you how much (or how little) of a substance is safe.

The EWG has helped stir up considerable hysteria about cosmetic safety. Increasingly, we see articles, blog posts and videos put out by people who are repeating misinformation and who often have no idea what they are talking about. That this should lead to the targeting of essential oil constituents is highly ironic, considering the very real healing benefits that they have to offer – from skin cancer prevention, to the treatment of antibiotic-resistant infections. And it is happening because of ignorance. We seem to entering a new Dark Age, where truth is measured by Google hit numbers, and scientific fact no longer counts for anything. In some cases safety legislation, instead of reflecting the science, is usurping and replacing it. Another irony is how EU cosmetics legislation is regarded in North America with something approaching reverence while in Europe it is regarded as, at worst, a Nazi-based tyranny (I’m not making this up – there’s quite a conspiracy theory…) and at best, a major hassle.

References
Atanassova-Shopova S, Roussinov KS, Boycheva I 1973 On certain central neurotropic effects of lavender essential oil. II communication: studies on the effects of linalool and of terpineol. Bulletin of the Institute of Physiology, Bulgarian Academy of Sciences 15:149-156

De Groot, AC 1987 Contact allergy to cosmetics: causative ingredients. Contact Dermatitis 17:26-34

De Groot AC, Coenraads PJ, Bruynzeel DP et al 2000 Routine patch testing with fragrance chemicals in the Netherlands. Contact Dermatitis 42:184-185.

Fregert S, Hjorth N 1969 Results of standard patch tests with substances abandoned. Contact Dermatitis Newsletter 5:85

Frosch PJ, Pilz B, Andersen KE et al 1995 Patch testing with fragrances: results of a multicenter study of the European Environmental & Contact Dermatitis Research Group with 48 frequently used constituents of perfumes. Contact Dermatitis 33:333-342

Gilpin S, Maibach H 2010 Allergic contact dermatitis from farnesol: clinical relevance. Cutaneous & Ocular Toxicology 29:278-287

Hostýnek JJ, Maibach HI 2003a Is there evidence that anisyl alcohol causes allergic contact dermatitis? Exogenous Dermatology 2:230-233

Hostýnek JJ, Maibach HI 2003b Is there evidence that linalool causes allergic contact dermatitis? Exogenous Dermatology 2:223-229

Itoh M, Ishihara M, Hosono K et al 1986 Results of patch tests conducted between 1978 and 1985 using cosmetic ingredients. Skin Research 28(Suppl.2):110-119

Jenner PM, Hagan EC, Taylor JM et al 1964 Food flavorings and compounds of related structure I. Acute oral toxicity. Food & Cosmetics Toxicology 2:327-343

Letizia CS, Cocchiara J, Lalko J et al 2003 Fragrance material review on linalool. Food & Chemical Toxicology 41:943-964

Santucci B, Cristaudo A, Cannistraci C et al 1987 Contact dermatitis to fragrances. Contact Dermatitis 16:93-95

SCCNFP 1999 Opinion concerning fragrance allergy in consumers: a review of the problem. SCCNFP/0017/98 Final

Schnuch A, Uter W, Geier J et al 2007 Sensitization to 26 fragrances to be labelled according to current European regulation. Results of the IVDK and review of the literature. Contact Dermatitis 57:1-10

Vocanson M, Goujon C, Chabeau G et al 2006 The skin allergenic properties of chemicals may depend on contaminants – evidence from studies on coumarin. International Archives of Allergy & Immunology 140:231-238

Vocanson M, Valeyrie M, Rozières A et al 2007 Lack of evidence for allergenic properties of coumarin in a fragrance allergy mouse model. Contact Dermatitis 57:361-364

Robert Tisserand is internationally recognized for his pioneering work in many aspects of aromatherapy since 1969 and frequent contributor to the aromaconnection blog.

Posted by Blogmistress on June 22, 2011 in Aromatherapy, Essential Oils/Plant Extractions, Organizations, Regulatory Issues, Research, Safety/Toxicity, Science | Permalink | Comments (0) | TrackBack

November 30, 2010

The "oxygenation" myth

by Robert Tisserand

It is commonly believed in some aromatherapy circles that a major therapeutic benefit of essential oils derives from the fact that they are rich in oxygen; that they efficiently carry this oxygen to the body’s cells and tissues, and thus dramatically enhance our health. Jim Lynn, for example, writes the following paragraphs under the title “Essential Oils…Nature’s Answer To Oxygen Deficiency“:

If there is any one BIG reason for you to use essential oils everyday, it can be summed up in one word…OXYGEN! Essential oils are loaded (concentrated) with it, at least 50 times more oxygen than what the plants give off from which they are derived.

While essential oils may contain hundreds of different elements, three primary elements common to all oils are hydrogen, carbon and OXYGEN. So each time you inhale essential oils or apply them to your body, you are enriching your body with needed oxygen to purge toxins and fight off disease causing pathogens. This is why the use of essential oils on a daily basis can help you develop a superior immune system, and why people who use the oils (several times daily) seldom experience illness and disease.

One of the incredible aspects of essential oils is their ability to penetrate and carry nutrients through the cell wall to the cell nucleus. Dr. Radwan Farag, Ph.D., head of the bio- chemistry department at Cairo University, is the man accredited for documenting the oxygenating and antioxidant activity essential oils afford.

When the viscosity of blood is reduced, it’s velocity increases. By increasing its velocity, our blood is able to deliver greater amounts of oxygen to tissues. When essential oils are introduced to the blood stream, they increase circulation, thereby increasing oxygenation.

oxygen1Now here’s that same text, with added comment:

If there is any one BIG reason for you to use essential oils everyday, it can be summed up in one word…OXYGEN! Essential oils are loaded (concentrated) with it, at least 50 times more oxygen than what the plants give off from which they are derived. (How this “50 times” is calculated is left to the readers imagination, but we could compare oxygen in essential oils to atmospheric oxygen. Sea-level air contains 21% oxygen, and a 50 times greater concentration would be….well, impossible, as even five times would be more than 100%. Also, the predominant elements found in essential oil constituents are hydrogen and carbon, with oxygen, when it is found, a minor player. At best, a few essential oils might contain about the same concentration of oxygen as that found in the air. But that’s percent, not amount. There’s no way that essential oils could ever deliver as much oxygen as we inhale every time we breathe air.

While essential oils may contain hundreds of different elements (clue to ignorance of writer: there are only 94 naturally-occurring elements on planet Earth. And, only five of these can be found in essential oil constituents. All contain hydrogen and carbon (hence they are known as hydrocarbons) and some also contain oxygen. A few are found with nitrogen or sulfur.) three primary elements common to all oils are hydrogen, carbon and OXYGEN (yes, all essential oils probably do contain constituents with oxygen – but some, such as citrus oils, contain very little oxygen – only about 1%.) So each time you inhale essential oils or apply them to your body, you are enriching your body with needed oxygen to purge toxins and fight off disease causing pathogens. (There is an important difference between “free” or elemental oxygen, such as the oxygen found in the air we breathe, and “bound” or molecular oxygen, such as is found in some (NOT ALL!) essential oil constituents. Oxygen bound into a molecule has to be freed from its molecular chains before it can be used by the body as oxygen, and many oxygen-containing essential oil molecules do not release their oxygen when metabolized by the liver. When oxygen IS released, it often takes the form of potentially dangerous peroxides or free radicals. Of course it’s true that each time you inhale you enrich your body with oxygen, but essential oils have nothing to do with that process.) This is why the use of essential oils on a daily basis can help you develop a superior immune system, and why people who use the oils (several times daily) seldom experience illness and disease. (There’s an assumption here that more oxygen means a “superior” immune system. There’s also an assumption that people who use essential oils on a regular basis experience illness less often than those who don’t.)

One of the incredible aspects of essential oils is their ability to penetrate and carry nutrients through the cell wall to the cell nucleus. (There is no evidence that I am aware of showing that essential oil constituents can enhance the absorption of nutrients through cell walls, though it is a feasible concept. However, nutrients are not carried to the nucleus, they are stored in other parts of the cell.) Dr. Radwan Farag, Ph.D., head of the bio- chemistry department at Cairo University, is the man accredited for documenting the oxygenating and antioxidant activity essential oils afford. (Dr. Farag has published nothing about the “oxygenating” activity of essential oils. Nor has anyone else, as such a phenomenon does not exist. Dr. Farag has indeed published two papers about the antioxidant capacity of certain essential oils, and there are hundreds of articles published by other researchers on the same general subject. You will find Dr. Farag’s articles here and here). “Antioxidant” describes the capacity of those oils to protect the body from oxidative stress – damage to cells caused by oxygen in the form of reactive oxygen species, or free radicals. Oxygen can be beneficial, but it can also be harmful.

When the viscosity of blood is reduced, it’s velocity increases. By increasing its velocity, our blood is able to deliver greater amounts of oxygen to tissues. When essential oils are introduced to the blood stream, they increase circulation, thereby increasing oxygenation. (So essential oils, all of them apparently, increase the velocity of the circulation by thinning the blood, and thus cellular oxygenation is increased. It’s an interesting thought, though thinning the blood is dangerous in specific situations, such as before surgery, or in those with blood-clotting issues. Aerobic exercise, and its consequent effects on respiration, heart rate and blood circulation, is a less risky, more efficient, and time-tested way to maintain health through this type of mechanism: “Aerobic Exercise – Nature’s Answer to Oxygen Deficiency”.)

Essential oils, if anything, are part of nature’s answer to oxidative stress (at least some of them are), which is a direct or indirect cause of many health problems including stroke, sun damage and cancer. However, essential oils must themselves be protected from oxidation, a degenerative process in which they lose their freshness and their therapeutic potency. This dilemma was the subject of one of my lectures in Tokyo in September 2010: Oxidative Processes and Essential Oils.

To believe that essential oils, because they sometimes contain oxygen, are therefore able to beneficially oxygenate tissues and stimulate the immune system shows an ignorance of basic biology, and the way in which essential oils interact with the body. To cite academic articles about which you clearly understand nothing is extremely unwise. Jim, you’re giving aromatherapy a bad name. And your spelling is pretty awful, which doesn’t help. I’m just saying. Similar nonsense about essential oils and oxygenation can be found here, here, here, and on many other websites.

Robert Tisserand is internationally recognized for his pioneering work in many aspects of aromatherapy since 1969 and frequent contributor to the aromaconnection blog.

Posted by Blogmistress on November 30, 2010 in Aromatherapy, Education | Permalink | Comments (5) | TrackBack

August 09, 2010

Advice for Aromatherapists and Natural Perfumers re: H.R. 5786 Safe Cosmetics Act 2010

Samara Botane Products You may think if you are a natural perfumer,  aromatherapist, massage therapist, or other alternative practitioner using essential oils or other raw botanical extracts or materials in your practice, craft or art,  that this bill will not directly affect you. At least you don’t think so.  However, you could be dead wrong.  If you are not a licensed doctor (M.D. or D.O. have the broadest authority) who can legally write a prescription, then you may be at risk under H.R. 5786 if you make essential oil blends or synergies for your clients or natural perfumes sold to clients (the general public). Thus far, essential oils have not been legally designated as either prescription or over-the-counter drugs.  The definition most used is, “A volatile oil, usually having the characteristic odor or flavor of the plant from which it is obtained, used to make perfumes and flavorings.”  In other words, they are manufacturing ingredients.

In H.R. 5786 (subchapter B), the definition of ‘ingredient’ reads:

“The term ‘ingredient’ means a chemical in a cosmetic, including - -
(A)  chemicals that provide a technical or functional effect;
(B)  chemicals that have no technical or functional effect in the cosmetic but are present by reason of having been added to a cosmetic during the processing of such cosmetic;
(C)  processing aids that are present by reason of having been added to a cosmetic during the processing of such cosmetics;
(D)  substances that are present by reason of having been added to a cosmetic during processing for their technical or functional effect;
(E)  contaminants present at levels above technically feasible detection limits;
(F)  contaminants that may leach from container materials or form via reactions over the shelf life of a cosmetic and that may be present at levels above technically feasible detection limits;
(G)  the components of a fragrance, flavor, or preservative declared individually by their appropriate label names; and
(H)  any individual components of a botanical, petroleum-derived, animal-derived, or other ingredient that the Secretary determines to be considered an ingredient. 

It is probably worth your while to ponder these definitions and take in their full impact.

Here in Washington state, the definition of ‘manufacturing’ in the state revenue code (RCW) reads:

"Manufacturer" means every person who, either directly or by contracting with others for the necessary labor or mechanical services, manufactures for sale or for commercial or industrial use from his or her own materials or ingredients any articles, substances or commodities.” (RCW 82.04.110)

"To manufacture" embraces all activities of a commercial or industrial nature where labor or skill is applied, by hand or machinery, to materials so that as a result thereof a new, different or useful substance or article of tangible personal property is produced for sale or commercial or industrial use . . . “

As you can see, this definition applies to the individual ‘person’, whether they are registered or incorporated as a business or not.  We can find similar manufacturing legislation in every state of the Union.  There is no exemption for individual practitioners, as many would define themselves.

I urge all, whether large corporations, small businesses or individuals to become more aware of the growing legislative efforts across the world that may affect the use of essential oils.  Please join the other 3,593 (and growing) signers in the advocacy efforts to oppose H.R. 5786 and make a point to stay abreast of similar legislative issues.  

Posted by Blogmistress on August 9, 2010 in Aromatherapy, Essential Oils/Plant Extractions, Massage, Perfumery, Regulatory Issues | Permalink | Comments (3) | TrackBack

February 16, 2010

Notes & News

The authors at aromaconnection have been otherwise occupied and we apologize that it’s been rather silent here of late.  We’ll be placing some major reprints of interest in the next few days.  In the meantime, here are a couple of items in the news.

According to Cosmeticsdesign.com, the EPA has issued the first of its Chemical Action Plans (CAPs) that appear to strengthen the agency’s authority regarding laws that protect Americans from exposure to harmful chemicals.  With this move, the EPA appears to have a new focus on phthalates and is, of course, challenged by the American Chemistry Council (ACC).  The complete EPA Phthalates Action Plan can be read here. In addition to being used as a chemical ingredient to soften vinyl plastics, Diethyl phthalates (DEP) are used as a dispersing agent for reed diffusers, a popular method of adding fragrance to the household environment. Most natural products companies avoid use of DEP and you will find cautions for its use from aromatherapy companies who choose to not use synthetic chemicals.   The EPA has previously established the Endocrine Disruptor Screening Program beginning in 2009, with the Notice of Tier 1 Screening of the first 67 chemicals to be evaluated (order issuance for Diethyl phthalate Jan 2010).  We will be watching the evaluations and update EPA resolutions as they come about.

Robert Tisserand has launched a new website which includes his I’m Just Saying blog which is a welcome new addition to internet discussions surrounding aromatherapy and the use of essential oils.

Posted by Blogmistress on February 16, 2010 in Aromatherapy, Education, Notes and News, Regulatory Issues, Safety/Toxicity | Permalink | Comments (0) | TrackBack

August 17, 2009

Notes and News

A distillation of Kashmiri rose oil was contaminated by geranium oil after the still was found to have not been thoroughly cleaned before the rose distillation began earlier this spring, reports R.P. Adams, Baylor University, and A.S. Shawl Regional Research Laboratory (CSIR) in August P&F. 

Earthoil has been awarded IMO (Institute for Marketology) Fair for Life for its Indian mint-growing operation in Uttar Pradesh.  Earthoil purchases from a 600+ farmer cooperative. 

Light Fare
This article shows that bird brains aren’t so small after all. 
Healthy Herbs and Spices
It’s that time of year; take a break and visit a lavender farm.  This article features escapes to Sonoma Valley where lavender grows among the wine grapes, CA. 

Posted by Blogmistress on August 17, 2009 in Aromatherapy, Ecological/Cultural Sustainability, Essential Oils/Plant Extractions | Permalink | Comments (0) | TrackBack

July 29, 2009

Notes and News

Those involved in natural cosmetics and the manufacture of aromatherapy products  in the United States are not always aware of what’s percolating in regulatory circles across the pond.  There is a searchable database, COSING, established by the EU, which is extremely helpful to quickly find pertinent information.  These regs may or may not appear in our own rules here at home as the FDA continues to masticate on the globalization act of 2008.   Of the greatest interest, rules regarding the 26 fragrance allergens now required to be labeled on cosmetic packaging if in products above 10 ppm in leave-on products, or 100-ppm in wash-off products.  Perhaps 50% of these allergens are found naturally in limonene, citronellal and linalool . . . all which occur in essential oils.  In this directive, fragrance allergens are considered regardless if they come from essential oils or synthetic manufacture. 

We owe great thanks to Tony Burfield for his diligence over the past two years to provide information here on aromaconnection about EU directives, IFRA and other regulatory issues.

The volunteers at aromaconnection have all been very busy with other aspects of their lives for a bit of time, however, we hope to be back stronger than ever by the fall.      

Posted by Blogmistress on July 29, 2009 in Aromatherapy, Organizations, Perfumery, Politics, Regulatory Issues, Safety/Toxicity, Trade Issues | Permalink | Comments (0) | TrackBack

May 19, 2009

Cropwatch at the SCS Symposium, Grantham UK, 2009

Tony Burfield gave a talk entitled “Legislators & Natural Aromatics: a Modern Day Vendetta” at the Symposium on Cosmetic Controversies –Seeing the Whole Picture organised by the Society of Cosmetic Scientists, May 17-19th 2009. Power Point and pdf versions of the above presentation can be viewed in the newly reorganised Cropwatch Files section of the Cropwatch website. Matthias Vey of IFRA spoke immediately after Cropwatch, his talk being entitled “How Safe are Fragrance Raw Materials? The IFRA Principles for Safety Assessment.” In the interests of balance, we hope it eventually becomes possible to run both talks side by side, and for both parties to answer the other’s criticisms.

Looking to the future, Cropwatch has plans to become a funded operation later this year. Although we continue to expand our available data on natural products on the Cropwatch website, and to attract new Cropwatch Newsletter subscribers, and we continue to regularly receive pledges of support from many quarters, we feel that there is a limit to what can be practically achieved without funding. Our intention therefore is to run a series of courses in order to raise the necessary finance, which is to be spent on research into some of the contentious areas of aroma ingredient toxicity, which Cropwatch has previously identified. We hope to be able to announce the subjects and venues for the courses in due course.

Tony Burfield
Cropwatch.

Posted by Tony Burfield on May 19, 2009 in Aromatherapy, Essential Oils/Plant Extractions, Lavender/Tea Tree/Gynecomastia, Perfumery, Regulatory Issues, Safety/Toxicity, Standards | Permalink | Comments (0) | TrackBack

June 08, 2008

Natural Beauty Summit tackles certification fragmentation

Cosmetics Design-Europe reported on the natural Beauty Summit held last month in New York with the headline Natural Beauty Summit tackles certification fragmentation.  We reported in this blog on the Summit before it happened, and although we were unable to attend, have been gathering information that goes beyond the sketchy report in CD-E, and we'll be reporting more in depth about the various standards and the process of their development in the near future.

Apparently the discussion got rather heated as the panel made presentations focusing on six different approaches to standardization for certification of natural and organic personal care products in North America: the USDA NOP, a Retailer's standard proposed by Whole Foods markets, Organic standards proposed by NSF and OASIS. CD-E referred to the NSF standard as being for consumer goods, but it appears to us to be equivalent to the OASIS standard and they seem to be two wheels on the same unicycle.

However, when it came to the panel discussion, Horst Rechelbacher, founder of Weleda and Intelligent Nutrients, and chair for the conference's first session on Sustainability, chose to challenge the panel on the fact that they were contributing to the fragmentation of the certification process and consumer confusion.

The panel discussion became heated, with Rechelbacher accusing the panel representatives of being self-serving and panel members defending themselves by explaining that the development of the market in the US had made private certification necessary.

Rechelbacher apologized for his comments, but stressed that he wanted to see greater regulatory harmonization.

The Natural Products standard proposed by the NPA apparently wasn't included in the discussion. As we pointed out in our discussion of that standard (see link) the orderly Standards development process mandated by ANSI isn't being followed by most of the standards developers. The one exception is the standard being proposed by NSF, which is going through the ANSI standards development process and has gone through it's first round of review, although the public has apparently not been brought in on the process yet. And neither have the independent small producers.

Coming soon: a comparison of the NSF and OASIS organic standards.

Posted by Rob on June 8, 2008 in Aromatherapy, Politics, Regulatory Issues, Standards | Permalink | Comments (0) | TrackBack

June 04, 2008

New Study Confirms psychoactive effect of [Frank]incense

A new study published in the The FASEB Journal, a journal of experimental biology

"found that incensole acetate, a Boswellia resin constituent, when tested in mice lowers anxiety and causes antidepressive-like behavior.” 

The press release goes on to cite this study as an explanation of how burning incense may have had a spiritual effect--a fact that is obvious to holistic aromatherapists. The significance of this study is that the study the mechanism that causes the effect was discovered.

There is an earlier study (2) on the anti-inflammatory effects of  Boswellia by the same authors that isolated the compound from Boswellia carterii, the common frankincense. The study authors suggest that the exact mechanism of the effect may be by activating TRPV3 that is found in neurons throughout the brain. TRPV3 is an ion channel implicated in the perception of warmth in the skin, as well as in the brain.

For this study, the incensole acetate was injected intraperitoneally into the mice, and then the mice were subjected to behavioral tests. A control group of mice that were known to be insensitive to TRPV3 stimulation was also used.

The psychoactive effects of frankincense are well known to aromatherapists, who are also aware that the the burnt resin has entirely different chemical composition than the essential oil components(3). Since the administration in this case was by injection and because incensole acetate is a (relatively minor - 2.3%) constituent of the essential oil there may be a different effect through inhalation of the essential oil; in any case this study did not address that. Reference (4) studied the Pyrolysates (burnt products) and found that insensole rises to 22% and incensyl acetate to 15.5%, so the effect may be greater when incense is used.

The study has been widely reported on in the scientific media, but as usual the press release was used as the major source and no one appears to have asked any interesting questions, which are answered in the full paper.

It would be interesting to see this study repeated using the essential oil.

References:

(1) Arieh Moussaieff et al. Incensole acetate, an incense component, elicits psychoactivity by activating TRPV3 channels in the brain, Published online before print May 20, 2008 as doi: 10.1096/fj.07-101865. Abstract at http://www.fasebj.org/cgi/content/abstract/fj.07-101865v1

(2) Arieh Moussaieff et al. Incensole acetate: a novel neuroprotective agent isolated from Boswellia carterii, Journal of Cerebral Blood Flow & Metabolism advance online publication 16 April 2008; doi: 10.1038/jcbfm.2008.28. Abstract at http://www.nature.com/jcbfm/journal/vaop/ncurrent/abs/jcbfm200828a.html

(3) Lis-Balchin, Maria.  Aromatherapy Science: A guide for healthcare professionals. Pharmaceutical Press: 2006. p. 193.

(4)  Basar, Simla. Phytochemical Investigations on Boswellia Species. Dr. dissertation. University of Hamberg 2005. Online at http://deposit.ddb.de/cgi-bin/dokserv?idn=975255932&dok_var=d1&dok_ext=pdf&filename=975255932.pdf

Posted by Rob on June 4, 2008 in Aromatherapy, Essential Oils/Plant Extractions, Incense, Research | Permalink | Comments (1) | TrackBack