Citronella oil
{{Short description|Fragrant essential oil derived from lemongrass}}
{{Other uses|Citronella (disambiguation){{!}}Citronella}}
file:Óleo de citronela.jpgCitronella oil is an essential oil obtained from the leaves and stems of different species of Cymbopogon (lemongrass). The oil is used extensively as a source of perfumery chemicals such as citronellal, citronellol, and geraniol. These chemicals find extensive use in soap, candles and incense, perfumery, cosmetic, and flavouring industries throughout the world.{{cite book |last1=Lawless |first1=J. |title=The Illustrated Encyclopedia of Essential Oils |year=1995 |publisher=Element |isbn=1-85230-661-0}}{{page needed|date=December 2013}}
Citronella oil is also a plant-based insect repellent and has been registered for this use in the United States since 1948.{{cite web | title=U.S. EPA Citronella Factsheet |url=http://www.epa.gov/opp00001/chem_search/reg_actions/registration/fs_PC-021901_01-Nov-99.pdf | access-date=June 9, 2014 }} The United States Environmental Protection Agency considers oil of citronella as a biopesticide with a non-toxic mode of action.{{Cite web |url=http://www.epa.gov/oppsrrd1/REDs/factsheets/3105fact.pdf |title=EPA citronella reregistration fact sheet }}
Citronella oil has strong antifungal properties.{{cite journal |id={{INIST|15524982}} |last1=Nakahara |first1=Kazuhiko |last2=Alzoreky |first2=Najeeb S. |last3=Yoshihashi |first3=Tadashi |last4=Nguyen |first4=Huong T. T. |last5=Trakoontivakorn |first5=Gassinee |title=Chemical Composition and Antifungal Activity of Essential Oil from Cymbopogon nardus (Citronella Grass) |journal=Japan International Research Center for Agricultural Sciences | date=October 2003 |volume=37 |issue=4 |pages=249–52}}{{cite journal |id={{INIST|3245986}} |pmid=8893526 |year=1996 |last1=Pattnaik |first1=S |last2=Subramanyam |first2=VR |last3=Kole |first3=C |title=Antibacterial and antifungal activity of ten essential oils in vitro |volume=86 |issue=349 |pages=237–46 |journal=Microbios}}{{cite journal |doi=10.1186/1472-6882-6-39 |year=2006 |last1=Prabuseenivasan |first1=Seenivasan |last2=Jayakumar |first2=Manickkam |last3=Ignacimuthu |first3=Savarimuthu |journal=BMC Complementary and Alternative Medicine |volume=6 |pages=39 |pmid=17134518 |title=In vitro antibacterial activity of some plant essential oils |pmc=1693916 |doi-access=free }}
Types
Citronella oil is classified in trade into two chemotypes: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 {{cite web |url=http://www.ics.trieste.it/Documents/Downloads/df4658.pdf |title=Archived copy |access-date=2007-09-06 |url-status=dead |archive-url=https://web.archive.org/web/20070716050943/http://www.ics.trieste.it/Documents/Downloads/df4658.pdf |archive-date=2007-07-16 }}
= Ceylon type =
- CAS: 89998-15-2
- CAS: 8000-29-1
- EINECS: 289-753-6
- FEMA: 2308
- CoE: 39
- Obtained from: Cymbopogon nardus Rendle
- Main components: citronellal (5–15%), geraniol (18–20%) and geranyl acetate (2%), citronellol (6–8%), limonene (9–11%), and methyl isoeugenol (7–11%).
= Java type =
- CAS: 91771-61-8
- CAS: 8000-29-1
- EINECS: 294-954-7
- FEMA: 2308
- CoE: 2046
- Obtained from: Cymbopogon winterianus Jowitt
- Main components: citronellal (32–45%), geraniol (21–24%) and geranyl acetate (3–8%), citronellol (11–15%), limonene (1–4%).
The higher proportions of citronellal and geraniol in the Java type oil make it a better source for perfumery derivatives.Online referenced article, Torres, R.C., Tio, BDJ, Citronella oil industry: challenges and breakthroughs [http://mis.dost.gov.ph/itdi/R&D/cmd/CITRONELLA_OIL.pdf] {{webarchive|url=https://web.archive.org/web/20040312225730/http://mis.dost.gov.ph/itdi/r%26d/cmd/CITRONELLA_OIL.pdf|date=2004-03-12}} The standard quality of Java type from Indonesia is regulated by Indonesian authority under SNI 06–3953–1995, which requires citronellal minimum 35% and total geraniol minimum 85%.IOP Conference Series: Materials Science and Engineering - "Essential Oil Extraction From Citronella Stems (Cymbopogon winterianus) By Vacuum Distillation" https://iopscience.iop.org/article/10.1088/1757-899X/1053/1/012119/pdf
Both types probably originated from Mana Grass of Sri Lanka, 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.
Insect repellent
File:Repellency of lemongrass oil against stable flies - Figure 2.tif, demonstrating repellency of citronella oil {{cite journal |doi=10.1051/parasite/2013021 |title=The repellency of lemongrass oil against stable flies, tested using video tracking |year=2013 |last1=Baldacchino |first1=Frédéric |last2=Tramut |first2=Coline |last3=Salem |first3=Ali |last4=Liénard |first4=Emmanuel |last5=Delétré |first5=Emilie |last6=Franc |first6=Michel |last7=Martin |first7=Thibaud |last8=Duvallet |first8=Gérard |last9=Jay-Robert |first9=Pierre |journal=Parasite |volume=20 |pages=21 |pmid=23759542 |pmc=3718533 }}
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Citronella oil is used especially as a mosquito repellent,{{cite journal |doi=10.1111/j.1748-5967.2005.tb00146.x |title=Evaluation of Repellency Effect of Two Natural Aroma Mosquito Repellent Compounds, Citronella and Citronellal |year=2005 |last1=Kim |first1=Jeong-Kyu |last2=Kang |first2=Chang-Soo |last3=Lee |first3=Jong-Kwon |last4=Kim |first4=Young-Ran |last5=Han |first5=Hye-Yun |last6=Yun |first6=Hwa Kyung |journal=Entomological Research |volume=35 |issue=2 |pages=117–20|s2cid=85112045 }} particularly for Aedes aegypti (dengue fever mosquito).{{cite journal |doi=10.1002/ptr.1637 |title=Comparative repellency of 38 essential oils against mosquito bites |year=2005 |last1=Trongtokit |first1=Yuwadee |last2=Rongsriyam |first2=Yupha |last3=Komalamisra |first3=Narumon |last4=Apiwathnasorn |first4=Chamnarn |journal=Phytotherapy Research |volume=19 |issue=4 |pages=303–9 |pmid=16041723|s2cid=23425671 }} Research also indicates that citronella oil is an effective repellent for body lice, head lice, and stable flies.{{cite journal |doi=10.1111/j.1570-7458.1996.tb00795.x |title=Repellency of essential oils and their components to the human body louse, Pediculus humanus humanus |year=1996 |last1=Mumcuoglu |first1=Kosta Y. |last2=Galun |first2=Rachel |last3=Bach |first3=Uri |last4=Miller |first4=Jacqueline |last5=Magdassi |first5=Shlomo |journal=Entomologia Experimentalis et Applicata |volume=78 |issue=3 |pages=309–14|s2cid=84889511 |doi-access=free }}{{cite journal |pmid=15609890 |url=http://www.ima.org.il/IMAJ/ViewArticle.aspx?year=2004&month=12&page=756 |year=2004 |last1=Mumcuoglu |first1=KY |last2=Magdassi |first2=S |last3=Miller |first3=J |last4=Ben-Ishai |first4=F |last5=Zentner |first5=G |last6=Helbin |first6=V |last7=Friger |first7=M |last8=Kahana |first8=F |last9=Ingber |first9=A|display-authors=3 |title=Repellency of citronella for head lice: Double-blind randomized trial of efficacy and safety |volume=6 |issue=12 |pages=756–9 |journal=The Israel Medical Association Journal }} A study conducted by DARPA in 1963 determined that hydroxycitronellal was an effective repellent against both aquatic and terrestrial leeches.{{Cite web|url=http://www.dtic.mil/dtic/tr/fulltext/u2/413979.pdf|archive-url=https://web.archive.org/web/20150418063847/http://www.dtic.mil/dtic/tr/fulltext/u2/413979.pdf|archive-date=18 April 2015|title=Dtic.mil}}
Citronella candles (which burn wax mixed with citronella oil) are not effective at repelling mosquitos such as Aedes aegypti, the species of mosquito responsible for spreading dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents.{{Cite journal |last=Pearson |first=Gwen |date=2017-02-16 |title=Want to repel mosquitoes? Don’t use citronella candles |url=http://www.sciencemag.org/news/2017/02/want-repel-mosquitoes-don-t-use-citronella-candles |journal=Science |doi=10.1126/science.aal0773 |issn=0036-8075|url-access=subscription }}{{Cite journal |last=Rodriguez |first=Stacy D. |last2=Chung |first2=Hae-Na |last3=Gonzales |first3=Kristina K. |last4=Vulcan |first4=Julia |last5=Li |first5=Yiyi |last6=Ahumada |first6=Jorge A. |last7=Romero |first7=Hector M. |last8=De La Torre |first8=Mario |last9=Shu |first9=Fangjun |last10=Hansen |first10=Immo A. |date=2017-01-01 |title=Efficacy of Some Wearable Devices Compared with Spray-On Insect Repellents for the Yellow Fever Mosquito, Aedes aegypti (L.) (Diptera: Culicidae) |url=https://academic.oup.com/jinsectscience/article/17/1/24/2996380?login=false |journal=Journal of Insect Science |volume=17 |issue=1 |pages=24 |doi=10.1093/jisesa/iew117 |issn=1536-2442|pmc=5388317 }}{{Cite web |title=FAQs What can homeowners do to reduce mosquito bites |url=https://www.mosquito.org/faqs/# |access-date=2024-12-17 |website=American Mosquito Control Association |language=en-US}}
Although direct application of citronella oil to the skin is non-toxic, its use was not recommended as a topical insect repellent in Canada in 2006.{{Cite web |url=http://www.cbc.ca/news2/background/consumers/citronella.html |title=Citronella FAQs |publisher=CBC|date=26 September 2006 }}{{cite web |vauthors=Bond C, Buhl K, Stone D |title=Oil of citronella: General fact sheet |url=http://npic.orst.edu/factsheets/citronellagen.html |publisher=US National Pesticide Information Center, Oregon State University Extension Services |access-date=6 November 2023 |date=2013}} Health Canada banned use of citronella oil as an insect repellent in 2012, but lifted the ban in February 2015.{{Cite web |url=http://www.cbc.ca/news/business/citronella-bug-spray-makes-comeback-after-public-pressure-1.2962142|date=19 February 2015|accessdate=6 November 2023 |title=Citronella bug spray makes comeback after public pressure |last=Harris |first=Sophia |publisher=CBC }}
World production
At present, the world annual production of citronella oil is approximately 4,000 tonnes. The main producers are China and Indonesia - producing 40 percent of the world's supply. The oil is also produced in Taiwan, Guatemala, Honduras, Brazil, Sri Lanka, India, Argentina, Ecuador, Jamaica, Madagascar, Mexico, and South Africa.{{Citation needed|date=November 2023}}
The market for natural citronella oil has been eroded by chemicals synthesised from turpentine derived from conifers. However, natural citronella oil and its derivatives are preferred by the perfume industry.FOODNET, The Association for Strengthening Agricultural research in Eastern and Central Africa {{cite web |url=http://www.foodnet.cgiar.org/market/Tropcomm/part2c1.htm |title=FoodNet | Market Information | Tropical Commodities | Commodities C 1 |access-date=2008-04-13 |url-status=dead |archive-url=https://archive.today/20120803225428/http://www.foodnet.cgiar.org/market/Tropcomm/part2c1.htm |archive-date=2012-08-03 }}