View source for Lemon Myrtle

{{Taxobox
| color = lightgreen
| image = Backhousia citriodora.jpg|370px
| image_caption = ''Backhousia citriodora'', garden specimen, in flower
| name = Lemon myrtle
| regnum = [[Plant]]ae
| divisio = [[flowering plant|Magnoliophyta]]
| classis = [[dicotyledon|Magnoliopsida]]
| subclassis = [[Rosidae]]
| ordo = [[Myrtales]]
| familia = [[Myrtaceae]]
| genus = ''[[Backhousia]]''
| species = '''''B. citriodora'''''
| binomial = ''Backhousia citriodora''
| binomial_authority = [[Ferdinand Jacob Heinrich von Mueller|F.Muell.]]
}}

''Backhousia citriodora'' (Lemon Myrtle, Lemon Scented Myrtle) is a [[flowering plant]] in the family [[Myrtaceae]], genus ''Backhousia'', native to subtropical rainforests of eastern [[Australia]]. Other common names are Sweet Verbena Tree, Sweet Verbena Myrtle, Lemon scented Verbena, and Lemon scented Backhousia.

It can reach 20 m in height, but is often smaller. The [[leaf|leaves]] are [[evergreen]], opposite, [[lanceolate]], 5-12 cm long and 1.5-2.5 cm broad, glossy green, with an entire margin. The [[flower]]s are creamy-white, 5-7 mm diameter, produced in clusters at the ends of the branches from summer through to autumn, after petal fall the calyx is persistent. 

Lemon myrtle was given the botanical name ''Backhousia citriodora'' in 1853 after the English botanist, [[James Backhouse]]. The common name reflects the strong [[lemon]] smell of the crushed leaves. 

Lemon myrtle is sometimes confused with "lemon ironbark", which is ''[[Eucalyptus staigeriana]]''.

==Essential oils==
''B.citriodora'' has two essential oil chemotypes: 

* The [[citral]] [[chemotype]] is more prevalent and is cultivated in Australia for [[flavouring]] and [[essential oil]]. Citral as an [[isolate]] in steam distilled lemon myrtle oil is typically 90-98%, and oil yield 1-3% from fresh leaf.  Citral purity is high when compared to other plant-based sources.

* The [[citronellal]] chemotype is uncommon, and can be used as an insect repellant.

==Uses==
[[Indigenous Australians]] have long used lemon myrtle, both in cuisine and as a healing plant. The oil is very high in [[citral]] content; typically higher than [[lemongrass]]. The leaves of the plant are used in cooking, forming one of the more well-known [[bushfood]] flavours.  It has an extensive range of uses, such as lemon flavouring in pasta, with fish, infused in [[macadamia]] or vegetable oils, and made into tea. It can also be used as a lemon replacement in milk-based foods, such as cheescake, lemon flavoured ice-cream and sorbet that would normally curdle due to lemon's citric acid. The taste/smell is similar to lemon (hence the name), verbena and lemongrass but not at all acidic. During former US President [[Bill Clinton]]'s visit to Australia in 1996, lemon myrtle tart was the dessert item at the formal reception hosted by the [[Australian Government]].  It is often described as "more lemon than lemon".

Lemon myrtle [[essential oil]] has also been shown to possess [[antimicrobial]] properties; however the undiluted essential oil is toxic to human cells ''[[in vitro]]''.<ref>Hayes AJ, Markovic B. "Toxicity of Australian essential oil Backhousia citriodora (Lemon myrtle). Part 1. Antimicrobial activity and in vitro cytotoxicity." Food Chem Toxicol. '''40(4)''':535-43 (2002). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11893412&query_hl=1 PubMed abstract]</ref> When diluted to approximately 1%, absorption through the skin and subsequent damage is thought to be minimal.<ref>Hayes AJ, Markovic B. "Toxicity of Australian essential oil Backhousia citriodora (lemon myrtle). Part 2. Absorption and histopathology following application to human skin." Food Chem Toxicol. '''41(10)''':1409-16 (2003). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12909275&query_hl=1 PubMed abstract]</ref> Use of lemon myrtle oil as a treatment for skin lesions caused by [[molluscum contagiosum virus]] (MCV), a disease affecting children and immuno-compromised patients, has been investigated. Nine of sixteen patients who were treated with lemon myrtle oil showed a significant improvement, compared to none in the control group.<ref>Burke BE, Baillie JE, Olson RD. "Essential oil of Australian lemon myrtle (Backhousia citriodora) in the treatment of molluscum contagiosum in children." Biomed Pharmacother. '''58(4)''':245-7 (2004). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15183850&query_hl=1 PubMed abstract], [http://www.catie.ca/catienews.nsf/0/66c00b8dec87f33185256ec10062a56b?OpenDocument CATIE summary]</ref>
The oil is a popular ingredient in health care and cleaning products, especially soaps, lotions and shampoos. It is marketed in the capitalized identity of Lemon Myrtle. The majority of commercial lemon myrtle is grown in Queensland and the north coast of [[New South Wales]], Australia.

==Cultivation==
Lemon myrtle is a cultivated ornamental plant. It can be grown from tropical to warm temperate climates, and may handle cooler districts provided it can be protected from frost when young. In cultivation it rarely exceeds about 5 metres and usually has a dense canopy. The principle attraction to gardeners is the lemon smell which perfumes both the leaves and flowers of the tree. Lemon myrtle is a hardy plant which tolerates all but the poorest drained soils. It can be slow growing but responds well to slow release fertilisers.

Seedling lemon myrtle go through a shrubby, slow juvenile growth stage, before developing a dominant trunk. Growing cuttings from mature trees bypasses the shrubby juvenile stage. Cutting propagation is also used to provide a consistent product in commercial production.

In plantation cultivation the tree is typically maintained as a shrub by regular harvesting from the top and sides. Mechanical harvesting is used in commercial plantations. It's important to retain some lower branches when pruning for plant health. The harvested leaves are dried for leaf [[spice]], or distilled for the essential oil.

==''Backhousia citriodora'' development==

Pre 1788 - Aboriginal people use ''B.citriodora'' for medicine and flavouring.

1888 – Bertram isolates [[citral]] from ''B.citriodora'' oil.<ref name="Simonsen">{{cite book | last = Simonsen | first = J. L. | title = The Terpenes, Vol. I | publisher = [[Cambridge University Press]] | date = Second Ed., 1953 | pages = 83-100 }}</ref>, and Messrs. Schimmel and Co., Dresden, write about the [[essential oil]] as having “…probably a future.” 

1900s-1920s - ''B.citriodora'' distilled on a small-scale commercial basis around Eumundi, Queensland.

1920s – Discovery of [[antimicrobial]] qualities of steam-distilled ''B.citriodora'' oil, by A.R. Penfold and R.Grant, Technological Museum, [[Sydney]].

1940s –  [[Tarax]] Co. use ''B.citriodora'' oil as a lemon [[flavouring]] during [[World War II]].

1989 – ''B.citriodora'' investigated as a potential spice and commercial crop by [[Peter Hardwick]], Wildnerness Foods Pty Ltd, in cunjunction with [[gas chromatography]] analysis of ''B.citriodora'' selections by Dr Ian Southwell, The Essential Oils Unit, Wollongbar Agricultural Institute.
 
1990 – Restaurants and food manufacturers supplied with dried ''B.citriodora'' leaf by [[Vic Cherikoff]], Bush Tucker Supply Pty Ltd, produced by Russel and Sharon Costin, Limpinwood Gardens.

1991 – ''B.citriodora'' plantation established by Dennis Archer and Rosemary Cullen-Archer, Toona Essential Oils Pty Ltd, ; and subsequent commercial supply of plantation produced ''B.citriodora'' oil in 1993.

Mid 1990s –  Large-scale plantations of ''B.citriodora'' established by Australian Native Lemon Myrtle Ltd.

Late 1990s – ''B.citriodora'' begins to be supplied internationally for a range of [[flavouring]], [[cosmetic]] and [[anti-microbial]] products. Agronomic production of ''B.citriodora'' starts to exceed demand.

2004 – Monograph published on ''B.citriodora'' by Toona Essential Oils pty Ltd.

==References==
* {{cite journal |author=Atkinson W, Brice H. |title=Antibacterial substances produced by flowering plants. |journal=Aust. J. Exp. Biology |volume=33 |pages=547-54 |year=1955}}
* [http://www.anbg.gov.au/cgi-bin/apx?taxon_id=49554 APNI Australian Plant Name Index]

==Footnotes==
{{reflist|2}}

==External links==
<!--*CSIRO Australian Native foods [http://www.clw.csiro.au/nativefoods/crops/myrtle.html Lemon Myrtle] page DOWN-->
*Article from  a [[Charles Sturt University]] magazine, Australia: [http://www.csu.edu.au/division/marketing/tms/102/102p6.htm "Are we getting the good oil on natural therapies?"]
* [http://guruna.com/forum/index.php Australian Bushfood and Native Medicine Forum]
* [http://www.dining-downunder.com/shop/index.php?main_page=product_info&cPath=1&products_id=33 Lemon Myrtle] from Vic Cherikoff
* [http://www.lemonmyrtle.com.au Broad range of lemon myrtle products and recipes]
* [http://allaboutlemonmyrtle.com ALL ABOUT LEMON MYRTLE JAPAN]

[[Category:Myrtaceae]]
[[Category:Myrtales of Australia]]
[[Category:Australian cuisine]]
[[Category:Bushfood]]