Citronella oil
Citronella oil is one of the essential oils obtained from the leaves and stems of different species of Cymbopogon. The oil is used extensively as a source of perfumery chemicals such as citronellal, citronellol and geraniol. These chemicals find extensive use in soap, perfumery, cosmetic and flavouring industries throughout the world.[1]
Citronella oil is also a renowned plant-based insect repellent, and has been registered for this use in the United States since 1948.[2] The EPA considers oil of citronella as a biopesticide with a non-toxic mode of action.[3] Research also shows that citronella oil has strong antifungal properties,[4][5] and effective in calming barking dogs.[6]
Types
Citronella oil is classified in trade into two chemotypes:[7]
- Ceylon type (obtained from Cymbopogon nardus Rendle) consists of geraniol (18-20%), limonene (9-11%), methyl isoeugenol (7-11%), citronellol (6-8%), and citronellal (5-15%).
- Java type (obtained from Cymbopogon winterianus Jowitt) consists of citronellal (32-45%), geraniol (11-13%), geranyl acetate (3-8%), limonene (1-4%). The higher proportions of geraniol and citronellal in the Java type make it a better source for perfumery derivatives.[8] [9] The name Cymbopogon winterianus is given to this selected variety to commemorate Mr. Winter—an important oil distiller of Ceylon, who first cultivated and distilled the Maha Pangeri type of citronella in Ceylon.
Both types probably originated from Mana Grass of Ceylon, which according to Finnemore (1962) occurs today in two wild forms--Cymbopogon nardus var. linnae (typicus) and C. nardus var. confertiflorus. Neither wild form is known to be used for distillation to any appreciable extent.
Citronella oil from Cymbopogon species should not be confused with other similar lemony oils from Corymbia citriodora and Pelargonium citrosum.
World production
At present, the world production of citronella oil is approximately 7,000 tonnes, the bulk of which is produced in Taiwan, Guatemala, Honduras, Indonesia, Brazil, China, Sri Lanka, India, Argentina, Ecuador, Madagascar, Mexico and the West Indies.
Use as an insect repellent
Citronella oil is popular as a 'natural' insect repellent. Its mosquito repellent qualities have been verified by research,[10] including effectiveness in repelling Aedes aegypti. [11][12] However, most citronella repellent formulas applied to the skin require reapplication after 30-60 minutes to remain efficient.[13]
Safety as repellent
Citronella may irritate skin and cause dermatitis in certain individuals. It should not be used on the skin of young children (under 3 years old).
The US Environmental Protection Agency states that citronella oil has little or no toxicity when used as a topical insect repellent, with no reports of adverse effects of concern over a 60 year period. Because some products are applied to human skin, EPA requires proper precautionary labeling to help assure safe use. If used according to label instructions in the US, citronella is not expected to pose health risks to people, including children and other sensitive populations.[14] The US Food & Drug Administration consider citronella oil as generally recognized as safe (GRAS).
Canadian regulatory concerns with citronella as an insect repellent are primarily based on data-gaps in toxicology, not on incidents.[15] [16] In Europe, Ceylon type citronella oil is placed on the category 3 list, with some safety concern regarding methyl eugenol.[17]
References
- ↑ Lawless, J., The Illustrated Encyclopedia of Essential Oils, 1995, ISBN 1-85230-661-0
- ↑ "U.S. EPA Citronella Factsheet". Retrieved July 20. Unknown parameter
|accessyear=ignored (|access-date=suggested) (help); Check date values in:|accessdate=(help) - ↑ * EPA citronella reregistration fact sheet
- ↑ Kazuhiko NAKAHARA*, Najeeb S. ALZOREKY1 , Tadashi YOSHIHASHI, Huong T. T. NGUYEN2 and Gassinee TRAKOONTIVAKORN, "Chemical Composition and Antifungal Activity of Essential Oil from Cymbopogon nardus (Citronella Grass)", Japan International Research Center for Agricultural Sciences (JIRCAS),(Tsukuba, Ibaraki 305–8686, Japan), JARQ - October 2003 - (Vol. 37 No. 4 )
- ↑ PATTNAIK S., SUBRAMANYAM V. R., KOLE C., 2006, "Antibacterial and antifungal activity of ten essential oils in vitro", Microbios, Vol. 86, No. 349, pp237-246 [1]
- ↑ Segelken, Roger (1996). "Study: 'Nuisance-barking' dogs respond best to citronella spray collars". Cornell Chronicle. Retrieved 2007-12-15.
- ↑ Chang, Yu Shyun, 2007, 8 Map species from Malaysia for ICS, Forest Research Institute Malaysia, Workshop on NFP, 28-29 May 2007, Nanchang, PR China[2]
- ↑ Lawless, J., The Illustrated Encyclopedia of Essential Oils, 1995, ISBN 1-85230-661-0
- ↑ Online referenced article, Torres, R.C., Tio, BDJ, Citronella oil industry: challenges and breakthroughs [3]
- ↑ Jeong-Kyu KIM, Chang-Soo KANG, Jong-Kwon LEE, Young-Ran KIM, Hye-Yun HAN, Hwa Kyung YUN, Evaluation of Repellency Effect of Two Natural Aroma Mosquito Repellent Compounds, Citronella and Citronellal, Entomological Research 35 (2), 117–120, 2005
- ↑ Ibrahim Jantan, and Zaridah Mohd. Zaki, Developemnt of environment-friendly insect repellents from the leaf oils of selected Malaysian plants, ASEAN Review of Biodiversity and Environmental Conservation (ARBEC), May 1998.
- ↑ Trongtokit Y, Rongsriyan Y, Komalamisra N, Apiwathnasom L, Comparative repellency of 38 essential oils against mosquito bites, Phytother Res. 2005 Apr;19(4):303-9 [4]
- ↑ "Test: Mosquito Repellents, The Verdict" Choice, The Australian Consumers Association
- ↑ "U.S. EPA Citronella Factsheet". Retrieved July 20. Unknown parameter
|accessyear=ignored (|access-date=suggested) (help); Check date values in:|accessdate=(help) - ↑ Re-evaluation of Citronella Oil and Related Active Compounds for Use as Personal Insect Repellents (PDF). Responsible Pesticide Use. Pest Management Regulatory Agency (Canada). 17 Sep 2004. ISBN 0-662-38012-6.
- ↑ "So Then: Who’s Afraid of Citronella Oil? Update!" Cropwatch Newsletter Vol 2,Issue 1, No. 1
- ↑ Chang, Yu Shyun, 2007, 8 Map species from Malaysia for ICS, Forest Research Institute Malaysia, Workshop on NFP, 28-29 May 2007, Nanchang, PR China[5]