Bergamot Oil
Citrus bergamia Risso et Poiteau. Family: Rutaceae
Bergamot , oleum bergamotte . Do not confuse with the mints Monarda didyma L. (scarlet bergamot or oswego tea) 1 or M. fistulosa L. (wild bergamot or horsemint). 2
 
Clinical Overview
Uses
Bergamot oil is widely used as a flavoring and scenting agent. Some of its components are useful in therapy for psoriasis and vitiligo.

Dosing
Bergamot oil is principally used in aromatherapy, therefore dosage is not relevant. Direct topical use should be discouraged due to psoralen photodermatotoxicity, while internal use may cause muscular cramping and should also be avoided.

Contraindications
Contraindications have not yet been identified.

Pregnancy/Lactation
Information regarding safety and efficacy in pregnacy and lactation is lacking. Avoid use.

Interactions
None well documented.

Adverse Reactions
Bergapten, a furocoumarin found in bergamot oil, has been shown to alter potassium channel currents, causing twitching and muscle cramps. There is a case report of a man 44 years of age who experienced muscle cramps, fasciculations, paresthesias, and blurred vision after consuming up to 4 L (approximately 1 gallon) of Earl Grey tea (flavored with bergamot oil) daily. All symptoms disappeared after switching to pure black tea.

Toxicology
Photosensitizing components can induce rashes and pathologic cellular changes.

 
Botany
The bergamot is a small tree native to tropical Asia that is cultivated extensively on the southern coast of Italy. The peel of the fresh, nearly ripe fruit is the source of bergamot oil. The oil is obtained by cold expression. Further purification by vacuum distillation, solvent extraction, or chromatography yields terpeneless (rectified) bergamot oil. 3 A synonym is C. aurantium L. subspecies bergamia .
 
History
Bergamot oil is used as a citrus flavor and is often added to perfumes and cosmetics. Bergamot oil is used to flavor Earl Grey tea. It is also commonly used to flavor halva, a Middle Eastern sesame paste confection.
 
Chemistry
Bergamot oil is a complex mixture of more than 300 compounds. The most prevalent compounds are linalyl acetate (30% to 60%), linalool (11% to 22%), and other alcohols. 3,  The quality of bergamot oil is determined according to the amounts of oxygenated compounds (ie, linalool and linalyl acetate). 4,  Furocoumarins include bergapten (approximately 0.4% 5-methoxypsoralen [5-MOP]) 5,  , bergamottin (5-geranyloxypsoralen), 5,  , 6,  citropten (5,7-dimethoxycoumarin), 5,  , 7,  and others. Rectified bergamot oil contains lower concentrations of terpenes and has no coumarins. 3
 
Uses and Pharmacology
Phytophotodermatitis is a nonimmunologic, chemical, and UVA radiation induced skin irritation. 8,  , 9 Skin reaction induced by UVA radiation on bergapten is called berloque dermatitis . A concentration of less than 0.3% bergamot oil has been recommended. Use of bergapten-free bergamot oil, especially in the United States, has decreased the incidence of berloque dermatitis . However, bergamot oil in fragrance formulations is used in some countries. Although the chance of berloque dermatitis has become rare, cases are reported caused by the use of older versions of perfumes, fragrant waters, and colognes. 8,  , 9,  , 10
The furocoumarins have been used therapeutically in conjunction with long-wave UV light therapy for the management of psoriasis and vitiligo.
 
Administration & Dosage
Bergamot oil is principally used in aromatherapy, therefore dosage is not relevant. Direct topical use should be discouraged due to psoralen photodermatotoxicity, while internal use may cause muscular cramping and should also be avoided.
 
Pregnancy/Lactation
Information regarding safety and efficacy in pregnacy and lactation is lacking. Avoid use.
 
Interactions
None well documented.
 
Adverse Reactions
Bergapten, a furocoumarin found in bergamot oil, has been shown to alter potassium channel currents, causing twitching and muscle cramps. There is a case report of a man 44 years of age who experienced muscle cramps, fasciculations, paresthesias, and blurred vision after consuming up to 4 L (approximately 1 gallon) of Earl Grey tea (flavored with bergamot oil) daily. All symptoms disappeared after switching to pure black tea.
 
Toxicology
Some furocoumarins (eg, bergapten and xanthotoxin, known as 5-MOP and 8-methoxypsoralen [8-MOP], respectively) have been shown to be phototoxic in humans. 3,  , 11,  Bergamottin accounts for about two thirds of the absorption of UVA and UVB light by bergamot oil. 12,  Photosensitivity can reach its peak from 2 to 72 hours after topical administration of the oil followed by irradiation. 11,  , 13,  Hyperpigmentation of the face and other areas exposed to the sun is thought to be because of the photosensitizing effects of cosmetics that contain these compounds. Phototoxic reaction can be affected by a variety of factors, including vehicle, concentration, hydration of skin, skin site, interval between local application of bergamot oil and irradiation, degree of skin pigmentation, and ability to tan. 11,  Inform patients of a potential phototoxic reaction caused by exposure to aerosolized bergamot aromatherapy oil with subsequent UVA exposure. 14
The furocoumarins can induce genetic changes in cells exposed to UV light even in concentrations as low as 5 ppm. 15,  These changes can be minimized by the application of a cinnamate-containing sunscreen, 16,  but sunscreens in low concentrations (up to 1%) added to perfumes cannot suppress the phototoxicity of bergamot oil on human skin. 10,  Studies suggest that many of the changes induced by bergamot oil and its components are malignant in nature. 15
 
References
 

1. Simon JE. Herbs: An Index Bibliography, 1971-1980 . Hamden, CT: The Shoestring Press; 1984.

 

2. Kershaw L. Edible and Medicinal Plants of the Rockies . Edmonton, AB Canada: Lone Pine Publishing; 2000;156.

 

3. Leung AY. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics . New York, NY: John Wiley and Sons; 1980.

 

4. Verzera A, et al. Effects of rootstock on the composition of bergamot ( Citrus Bergamia Risso et Poiteau) essential oil. J Agric Food Chem . 2003;51:206-210.  PubMed

 

5. Finsterer J. Earl Grey tea intoxication. Lancet . 2002;359:1484.  PubMed

 

6. Morliere P, Bazin M, Dubertret L, et al. Photoreactivity of 5-geranoxypsoralen and lack of photoreaction with DNA. Photochem Photobiol . 1991;53:13-19.  PubMed

 

7. Makki S, Treffel P, Humbert P, Agache P. High-performance liquid chromatographic determination of citropten and bergapten in suction blister fluid after solar product application in humans. J Chromatogr . 1991;563:407-413.  PubMed

 

8. Chew A, Maibach H. Berloque dermatitis. eMedicine.com. 2003. Available at: http://www.emedicine.com/derm/topic52.htm . Accessed Dec 8, 2003.

 

9. The Internet Dermatology Society, Inc. Botanical Dermatology-Phytophotodermatitis in: Electronic Textbook of Dermatology . 1995-2000. Available at: http://www.telemedicine.org/botanica/bot5.htm . Accessed Dec 8, 2003.

 

10. Wang L, Sterling B, Don P. Berloque dermatitis induced by "Florida water". Cutis . 2002;70:29-30.  PubMed

 

11. Zaynoun ST, Huppe G, Averbeck D, Young AR, Santus R, Dubertret L. A study of oil of bergamot and its importance as a phototoxic agent. II. Factors which affect the phototoxic reaction induced by bergamot oil and psoralen derivatives. Contact Dermatitis . 1977;3:225-239.  PubMed

 

12. Morliere P, Johnson BE, Frain-Bell W. In vitro photostability and photosensitizing properties of bergamot oil. Effects of a cinnamate sunscreen. J Photochem Photobiol B . 1990;7:199-208.  PubMed

 

13. Dubertret L, Serraf-Tircazes D, Jeanmougin M, Morliere P, Averbeck D, Young AR. Phototoxic properties of perfumes containing bergamot oil on human skin: photoprotective effect of UVA and UVB sunscreens. J Photochem Photobiol B . 1990;7:251-259.  PubMed

 

14. Kaddu S, Kerl H, Wolf P. Accidental bullous phototoxic reactions to bergamot aromatherapy oil. J Am Acad Dermatol . 2001;45:458-461.  PubMed

 

15. Young AR, Walker SL, Kinley JS, et al. Phototumorigenesis studies of 5-methoxypsoralen in bergamot oil: evaluation and modification of risk of human use in an albino mouse skin model. J Photochem Photobiol B . 1990;7:231-250.  PubMed

 

16. Averbeck D, Averbeck S, Dubertret L, Young AR, Morliere P. Genotoxicity of bergapten and bergamot oil in Saccharomyces cerevisiae . J Photochem Photobiol B . 1990;7:209-229.  PubMed