Australian Safrole Containing Plants

-=] ausaf - 2007 [=-

          The Basics

Plant Sources

Further Resources



    Hello, and welcome to what i hope provides an informative experience as well as a resource for those times to come...

    Here is the compilation of several years research into this area, and the author is keen to have been able to make this information available via the Internet, to the general public, in the hope of facilitating a broader appreciation for more of the beautiful and unique plants growing here in the land of oz. While illustrating an old saying that the difference between a "healing remedy" and a "deadly poison" might merely be the dose.

    Most if this information as been "outsourced" from others research with little original content by the author other than the odd comment and nature of presentation. Thus many thanks go out to those who made this possible by providing the inspiration, framework and connections which came together for the creation of this document.

So sit back, get uncomfortable, and let's get into it... ;p - enjoy


The Basics:   

    Safrole is an natural constituent of a number of plant oils and spices from around the world such as nutmeg, mace, cinnamon, anise, black pepper and sweet basil.

    Alone it takes the form of an oil at room temperature with the uniquely marking smell similiar to root beer or sasparilla, this is partly due to it being the major component of sassafras oil which itself lend the fragrance to root beer.

    It's density is greater than water so it would generally sit as a fraction (layer) below water apon distillation rather than on top as most other oils will.


    Safrole is no longer available for sale to the general public or business world (par approved research) due to severe legal classifications and restrictions being applied to it to control the sale, possession, production, and importation within Australian as well as most other countries.
    This began happenning around the 1950' s and 60's
    Whether a safrole containing oil or plant is illegal in Australia to possess and/or sell such as sassafrass or nutmeg oil is unknown to me, though commented to as not so, particularly in the later case of a plant.
    There are detailed below species containing safrole within Australia growing in some cases prolifically and all but one native. These are protected as are most native trees theses days to anyone being permitted to prune or fell them, even those outside of national and state parks/reserves.
    Permits have and may be granted to collectors for seed collecting of requested species through nurseries, as not all those listed below would be commercially available.
    Many of these plants could make a worthy addition to a garden be that ornamental or produce purposes, and could even be considered as an alternative crop if more land is available. These commercial aspects are touched on in the "Modern Day Uses" section below.
    Currently there are international regulations in place to set, reduce and eliminate safrole levels being allowed in foodstuffs and beverages via ingredients containing safrole, and pure safrole itself may not be added at all.

Traditional Use:

    There are many reports of the worlds native peoples and developed civilizations using safrole containing preparations for therapeutic uses, including both Australian aboriginals and the more relatively recent settlement/immigrating populations.

    Some of the ways both native aboriginals and other cultures have used these plants include making an infusion such as tea, crushing the leaves followed by inhalation, and burning the plant pieces for smoke.

    Australian Aborgnals used some of the plants listed below in preparations for eye, skin and body washes and as a counter irritant while in.the desert among other places.

    It is worth noting here that an infusion or tea/brew may lead to the loss via "distillation" (evaporation) of safrole and other essential oils in the steam if much steam is produced for an extended period in an unsealed/uncovered vessel.. 

    Another issue here with this preparation method could be the possible extraction of plant chemicals, such as alkaloids from the source material. Which in certain cases including some of the plants mentioned here, have a relatively specific enough toxicity which has been reported to lead to side-effects and/or possible health complications. This would generally not be an issue if making a steam distilled oil. 

    Sassafras (an american safrole containing tree) was used by Native Americans for many purposes, primarily for infections, gastrointestinal problems and as a spring blood tonic. It is still used today in many parts of the Appalachian Mountains, where the root is locally gathered.

    Other safrole bearing plants have also been used since way back by chinese herbalist practitioners..

    Topically, sassafras oil could relieve the pain and inflammation of insect bites. It may have some anti-infective properties, which might also help to prevent infection of bites and minor skin rashes. And has such been used as a topical antiseptic, a pediculicide (head and body lice treatment) and washes used to soothe the eyes.

    It has also been used by alternative medicine for treating high blood pressure, rheumatism, arthritis, gout, menstrual problems, colds, flu, and bronchitis, as a diuretic, for urinary tract disorders and kidney problems. Also as a liniment, and the treatment of bruises, swellings and skin complaints. 

    Other herbal practitioners gave it to women to ease painful menstruation and help their recovery from childbirth.

    The volatile oil (sassafras) was also used in dentistry in combination with cloves and other herbs to relieve toothache. By far the most common "western" use of sassafras, however, was to flavor root beer, and for a Sassafras tea, sold under the name saloop, which became a very popular beverage in London. 


Modern Use:

    The root bark and root pith, in areas, may still be used in alternative medicine as an alternative, anodyne, antiseptic, aromatic, carminative, diaphoretic, diuretic, stimulant and vasodilator. An Infusion is used to treat gastrointestinal complaints, colds, liver and kidney ailments, rheumatism skin eruptions and as a blood purifier.

    Safrole is an important raw material for the chemical industry because of two derivatives: heliotropin, which is widely used as a fragrance and flavoring agent, and piperonyl butoxide (PBO), a vital ingredient of pyrethroid insecticides. Natural pyrethrum in particular would not be an economical insecticide without the addiction of PBO as a synergist and the future of the natural pyrethrum industry is linked to the continued availability of PBO. Safrole has many fragrance applications in household products such as floor waxes, polishes, soaps, detergents, and cleaning agents. Oil of sassafras, which contains safrole, was formerly used to flavor some soft drinks, such as root beer. However, as of 1960, this use was no longer permitted in the U.S.A

    Further information detailing "old fashioned root beer" recipes involving sassafras root are available, online, thanks to numerous home brew enthusiasts from around the world.

A Commercial History (of the north American Sassafras albidum):

    How it all is supposed to have happened: Internet sources (which may or may not be accurate but are often cross-derived and, therefore, are often at least mercifully consistent) have it that Europeans exploring North America in the early 1500’s (probably the Spanish in Florida?) observed the medicinal use of (Sassafras albidum) by Native Americans, but thought that the plant was the East Indian cinnamon tree. This is understandable because, at the time, they thought that they were in India. Whatever, Sir Walter Raleigh, a one-time favorite of Queen Elizabeth I who was later executed for treason, is said to have created a major stir when he brought (Sassafras albidum) back to England from the “Virginia Colony”, in the very early 1600’s.

    Europeans got the idea that (Sassafras albidum) was a “wonder drug” that could cure almost anything, even the dreaded “new” disease syphilis which had appeared in Europe shortly after Christopher Columbus’ first return voyage. Even better yet, the belief somehow developed that (Sassafras albidum) would retard old age. (Sassafras albidum) does seem to have antibacterial and antiviral properties that are good, for example, at warding off colds.

    So, by the mid-1600’s, (Sassafras albidum) became the Americas’ number two export to Europe; number one being tobacco, and number three probably being cane sugar products such as molasses and rum. (The sugar cane itself probably originated in Polynesian but was definitely imported to Jamaica by Christopher Columbus in the 1500’s). 

    Following its stunning European debut, various parts of the (Sassafras albidum) tree came to be widely used in food and medicine. Sassafras oil, extracted from the root bark, was used to flavor many things. Root beer was named for the beverage’s major flavoring agents which, you guessed it, were the roots of our friend (Sassafras albidum), combined with fermented molasses (from cane sugar). People also ingested gallons of sassafras tea, believed to be healthful as well as delicious. (Sassafras albidum) leaves were ground up and widely sold as “filè” powder, a major Cajun seasoning and thickening agent.

        This all went on for some time until its use was prohibited.



    As with many plants containing essential oils, there can exist multiple "chemotypes" within a species. The composition of an oil extracted can vary depending on many factors resulting in plants of the same "cataloged" species and living in that same area having differing levels of constituents.

    The term chemotype is used to refer to a "sub-group" of a species which illustrates similar constitution.

    Apart from variation in chemotypes, essential oil yield and composition and can vary due to factors such as:

        time of day harvested
        climate and rainfall
        growing conditions
        flowering and seeding
        part of plant extracted
        health and age of plant

    When summarising the reports outlined below, generally only the chemotype with the highest levels of safrole is mentioned, so there quite often is results for the same "species"from a differing region for example that yield nearly no safrole.


    An awfully lot of reports have been released containing results relating towards the toxic properties of safrole.  Mostly supported by grants from various Foundations and Institutes. This has sparked some controversy and debate among various circles, as some of these provided the needed stepping stone to what has become a worldwide outlawing of safrole. These early experiments simply involved exposing various animals and isolated biological cells to enough safrole to give a result that would prove its toxicity. Most compounds both organic and not are "toxic" at high enough levels... even water. And what we may be seeing here in the form of "toxicity" may just be an over-amplified expression of what could have been and may still be an important part of human evolution. And that it could be seen as responsible for such serious and detrimental traits may simply be a result of how far out of context and exaggerated the potential levels of exposure have been taken. The human body and all living things have been seen and commented on as having astounding potential for adaptability and resilience, if not just for their survival amongst such a modernly polluted environment, full of things with well recorded toxicities and dangers that have been recorded on par and beyond that of safrole. Perhaps its banning and disregard came so easily to those responsible under the light that it had no

    Interestingly enough though, allot of the new reports being released, which are  more forward thinking and at home with a "ying yang" perspective on the human multi-verse are those coming out of china. The "some could say" mekka of medicinal herbal practice. Very much connected with a long traditional and possibly still modern day use of safrole containing plants.

Here is some extracts from just a few:

    An oral LD50 has been reported to be 1950 mg/kg bw for rats and 2350 mg/kg bw for mice. Compared with ...

    Liver tumors in mice and rats by oral administration (sometimes as high as 5000mg/kg); safrole also produces liver and lung tumors in male infant mice following its subcutaneous injection. The carcinogenic potency appears to be relatively low and dependent on the metabolism. Mice appear more susceptible than rats to the carcinogenic effects of safrole.
    Safrole is metabolically activated through the formation of intermediates able to directly react with DNA. Safrole is genotoxic in various in vitro mammalian cell systems causing induction of gene mutations, chromosomal aberrations, UDS and SCE. Several metabolites of safrole are directly mutagenic in Salmonella. In vivo, safrole was able to induce chromosome aberrations, SCE and DNA adducts in the liver of rats. -SCF/CS/FLAV/FLAVOUR/6 ADD3 Final , 9 January 2002

    Safrole is metabolized in the liver mainly by two pathways, one of these producing  1-hydroxysafrole which has been shown to be the preponderant proximate carcinogenic metabolite, which, following a further biotransformation can bind covalently to cellular DNA. -Toxicology Letters 75 (1995) 201-207

    Safrole was an inhibitor of human (cytochrome P450) enzymes primarily responsible for the oxidation (breaking down) of both internal (endogenous) and external (exogenous) chemicals including steroids, drugs, and chemical carcinogens.
    Methylenedioxybenzenes are the substrates, inducers, and inhibitors of P450. These P450 forms are responsive to the inductive and inhibitory effects of xeno-biotics including plant constituents. -Food and Chemical Toxicology 43 (2005) 707-712

    Safrole is a weak hepatocarcinogen, and its carcinogenic effect has been linked to the formation of stable safrole-DNA adducts. Results demonstrate that safrole has the potential to induce oxidative damage in vivo, and this damage may be blocked by antioxidant detoxification systems. This safrole induced oxidative damage may be involved in the hepatocarcinogenic effects of safrole. The most effective antioxidant tested was the precursor of glutathione, NAC (N-acetylcysteine)  which acts as a cysteine prodrug and can enhance GSH synthesis, a molecule which plays a central role in the elimination of electrophilic xenobiotics and in the defense of the cell against oxidative stress. The generation of oxidative stress has been linked to chemical carcinogenis.
     In vitro, safrole can be biotransformed to a redox-active o-quinone which may generate ROS (reactive oxygen species) and forms the basis of safrole-induced oxidative damage. This may explain why NAC was most efficient in reducing both of the safrole-induced oxidative markers in vivo since o-quinone is scavenged efficiently by GSH.
    Two other antioxidants tested which reduced the safrole-induced formation of biomarkers LHP(representative of either a less sever injury, or an early step in ROS-mediated safrole-induced hepatic injury.) but not 8-OH-dG (correlated to cyctotoxicity) where: vitamin E and deferoxamine, yet for a shorter time than NAC could.
      This study suggested that safrole caused lipid per-oxidation and oxidation DNA damages in rat liver. In addition, this study also demonstrated that this damage was rapidly repaired within 15 days after safrole treatment. -Food and Chemical Toxicology 37 (1999) 697-702

    Low concentrations of safrole oxide have been shown to induce HUVEC (human umbilical vein vascular endothelial cell) to phenomenonly make an irreversible switch from one type of already differentiated cell to another type of normal differentiated cell in postnatal life.
    In this case a transdifferentiation to neuron-like cells via the depression of intracellular ROS (reactive oxygen species) levels, which act as a intracellular messengers in signal transduction pathways.
    Recent studies show that productions of ROS lead to cell death or promote dysfunction. And that elevating ROS levels triggered apoptosis (natural self destruction) in HUVEC's.
    Thus illustrating a critical balance between the synthesis and destruction of ROS is likely to regulate the balance among the cellular process of proliferation , differentiation, and apoptosis.
    In addition, recently, ROS was suggested as inducers of neuronal differentiation, and some findings indicate that HUVEC's have the potential to differentiate into smooth muscle-like cells.
    It has also been reported that some antioxidants can induce MSC's (marrow stromal cells) and HUVEC's to differentiate into neurons too. -Biochimica et Biophysica Acta 1763 (2006) 247-253

    (L. S. Gold,, Science, vol. 258, pg 261, 9 Oct 92, "Rodent Carcinogens: Setting Priorities");

    Comparing instances of the cancer development response levels in rats to a life time of daily being fed synthetic or/vs natural carcinogens found from various sources, (including safrole in root beer). 

    A relative likely-hood of carcinogenicity can be illustrated such that 1 bottle (375ml) of traditional root beer containing 6.6mg of safrole has the equivalence to:

Note though that:
    Non monotonic effects occur in fruits and vegetables, which actually reduce your risk of cancer (when taken in moderation) due to the presence of anti carcinogenic antioxidants and vitamins.

 "though it (safrole/sassafras) is less likely to cause cancer than alcohol."

Medical Aid:
   Firstly i dont really think this is an issue, but if for some reason you wnid up with a large enough exposure to safrole somehow, here's the medico talk:

    (but also note though that if a humans LD50 to safrole is similar to a rats (it may be higher or lower), a 70kg adult would have to consume 138 grams (alot) of safrole  to give themselves a 50% chance of survival or death)

Expectations (prognosis):

    Deaths have been reported from taking sassafras or sassafras oil by mouth. Potentially life-threatening side effects such as rapid heartbeat and paralysis are also reported to have occurred. Ingesting or applying safrole-containing products may produce drowsiness, excessive sweating, high blood pressure, and vomiting.

    Survival past 48 hours is usually a good sign that recovery will occur. If damage to the kidneys has occurred, it may take several months to heal.


    * Lungs
          o Shallow breathing 
          o Rapid breathing
    * Skin
          o Burns 
    * Gastrointestinal
          o Abdominal pain
          o Diarrhea
          o Nausea
          o Vomiting
    * Heart and blood
          o Rapid heartbeat
          o Low blood pressure
    * Nervous system
          o Unconsciousness
          o Dizziness
          o Hallucinations

Possible Treatment:

    Consider seeking medical advice and/or treatment...

Plant Sources:

Atherosperma moschatum

Tasmania, Victoria and N.S.W. as far north as the Barrington Tops district

“The leaves yielded from 1.7 - 2.65% of oil, with an approximate safrole level of 5-10%."
 Identification by fractional distillation followed by b.p. , m.p. and density tests.
(Scott, J.Chem.Soc. 1912, 101, 1612)

Cinnamomum baileyanum

Far north Queensland from Cooktown to Capeyork, and  Fraser Island in the south

“The yield of bark oil was 0.6% of which 46% was safrole, the leaf oil yield of 0.1-0.3% had none.”
Analysis by GC and GC/MS.
(J. Essent. Oil Res., 13, 332-335, 2001)

Cinnamomum camphora

Most of habitable Australia

Though this is a relatively recently introduced species it has spread so much to the point in Australia that it is now a classified as a noxious weed...
“Certain chemo types have been found to yield a bark oil containing 50-80% safrole”
(Safrole Faq)

Cinnamomum laubatii

Coastal northern Queensland

“The leaf oil compositions indicated two chemotypes, one with no aromatic compounds and the second containing 10-40% of safrole from an oil yield of 0.3-0.4%.”
Analysis by GC and GC/MS.
(J. Essent. Oil Res., 13, 332-335, 2001)

Cinnamomum oliveri

Northern NSW and southern Queensland

 “The bark gave 0.4% oil, of which 25% was safrole.”
 Identification by fractional distillation followed by b.p. , m.p. and density tests.
(Hargreaves, J.Chem.Soc. 1916, 109, 751)

 “The leaf oil yield was 0.2-2.3%, the majority being >1%, of which 0.3-19% was safrole usually in inverse proportion to the camphor concentration.”
Analysis by GC and GC/MS.
(J. Essent. Oil Res., 13, 332-335, 2001)

Doryphora aromatica

Northern Queensland

 “The bark gave 0.3% of oil, consisting chiefly of safrole at 95%.”
 Identification by fractional distillation followed by b.p. , m.p. and density tests.
(Jones and Smith, Proc.Roy.Soc.Queensland, 1923, 35, 61-3 via P.E.O.R., 16, 179)  - (This abstract was read from a scan of a book quoting the original report)

 "The leaves contain no aromatic compounds (safrole)."
Analysis by GC and GC/MS.
(J. Essent. Oil. Res. 5, 581-586, 1993)

Doryphora sassafras

The south of Queensland down to the eastern districts of NSW from the blue mountains west of Sydney to as far west as the Jenolan caves.

 “The leaves yielded from 0.1 to 0.85% oil, of one district had 60-65% safrole and the other district had 30% safrole.”
 Identification by fractional distillation followed by b.p. , m.p. and density tests.

(J and Proc. Roy. Soc. N.S.W. 1921, 55, 270) 

“The fresh leaves had yields of 0.8 - 2% (14.71% safrole), 0.3% for the bark (14.88% safrole), and seed oil containing 13.04% safrole.”
Analysis by GC and GC/MS.
(J. Essent. Oil. Res. 5, 581-586, 1993)

Eremophila longifolia

Usually inland, continental Australia except extreme north

"Steam distillation of the leaves gave an aromatic oil in 5.8 % yield. Various levels of safrole content between collection groups where recorded via fractional distillation and gas chromatography at (i) 72%, (ii) 90% mean / 93% best, (iii) 37%, and (iv) 0%."
Australian Journal of Chemistry. 1961;14:663-664)


Zieria (Rutaceae)

Along the east coast from Victoria to Northern Queensland
(Australian Systematic Botany, 15, 277-463, 2002)

 “Steam-distillation of the foliage of subsp. Smithii resulted in high oil yields (0.5-8.3%, mean 3.1%), rich in either methyl eugenol, elemicin or safrole. The methyl eugenol rich samples occur throughout the species distribution in NSW; the elemicin rich samples occur in the coastal ranges from the Blue Mountains to south-eastern Queensland and the safrole rich samples are known from the coastal ranges in the south of NSW and from the south-eastern and central Queensland (South and Armstrong 1982, 1987).”

“Steam distillation of the foliage of subsp. Tomentose resulted in moderate volatile oil yields (mean 1.1%), safrole having a mean concentration of 9%.”



    "Just thought you might like to add some info onto your safrole FAQ sheet on your site. The Australian botanicals, southern sassafras and ziera smiithi have no safrole in their roots, bark, trunks or foliage. Southern sass has nothing worth mentioning whilst smiithi contains lots of methyl eugenol, which is where the confusion started I believe, the text 'poisionous plants of Australia' is fraught with errors and as much of the info in the current Safrole FAQ is lifted directly from this hence the errors. This will save readers much time I believe as I have wasted heaps of time collecting , seperating and steam distilling all the bits. The methyl eugenol's existence was confirmed through FTIR and NMR library matches so there is no doubt to the accuracy of this info. The only assumption I am making is that maybe safrole only seasonally appears in these species, as my samples were all collected in winter/spring."

It would seem this person most likely collected a chemo-type containing little or no safrole... :)


Further Resources:

    Apart from getting copies of the journals' mentioned above there are a few more relevant sources of information that may be of use to you:

The Australian Virtual Herbarium

A searchable database of recorded botanical plant collections'.

Ideal for getting approximate locations of where certain plants may be growing.
Though alot of the coordinates are very old and have low resolution of definity.
Not much work to download search results to a gps, but more involved in actually getting there to find nothing but a bare paddock or an airport...

Australian Tropical Rain Forest Plants (cdrom)

An interactive identification and information system for 2154 species of trees, shrubs and vines of northern Australian rain forests.

". . . represents the finest resource available for identifying rainforest plants in Australia and is a must for all those working in the area."
Chris Humphries (Plant Talk 34, Oct 2003)

"This program contains a wealth of information . . . I highly recommend this excellent program to identify and learn about woody plants and giant herbs in the Australian tropical rain forest."
Rudolf Schmid, UC (Taxon 52 May 2003)

Internet Forums

Information disseminates, finding's posted and general discussion.

Library's: Public, TAFE, University, Institute 

Access journals online or via inter-library loans, as well as read books.

Herbarium, Nurseries and Gardens 

Get yourself a fresh oxygen fix, while checkin' out actual specimens both alive and dried, or having your own collections/photos identified.

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