Bitter Orange

Common name: Seville Orange, Zhi Shi, Chongcao

Botanical names: Citrus x aurantium

Parts used and where grown

The dried outer peel of the fruit of bitter orange, with the white pulp layer removed, is used medicinally. The leaves are also commonly used in many folk traditions. The bitter orange tree is indigenous to eastern Africa, Arabia, and Syria, and cultivated in Spain, Italy, and North America.

Bitter orange has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Indigestion Loss of appetite
	Insomnia Weight loss
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Bitter orange is used similarly in a wide variety of traditions. In Mexico and South America the leaf is used as a tonic, as a laxative, as a sedative for insomnia, and to calm frazzled nerves.¹ ² The peel of the fruit is used for stomach aches and high blood pressure.³ ⁴ The Basque people in Europe use the leaves for stomach aches, insomnia, and palpitations and the bitter orange peel as an anti-spasmodic.⁵ In traditional Chinese medicine, the peel of the immature fruit is used for indigestion, abdominal pain, constipation, and dysenteric diarrhoea. Where the patient is weak, the milder, mature fruit is used similarly.⁶ Bitter orange continues to be widely used for insomnia and indigestion in many parts of the world.⁷

Active constituents

Bitter orange has a complex chemical make-up, though it is perhaps most known for the volatile oil in the peel. The familiar oily residue that appears after peeling citrus fruit, including bitter orange, is this volatile oil. It gives bitter orange its strong odour and flavour, and accounts for many of its medicinal effects. Besides the volatile oil, the peel contains flavones, the alkaloids synephrine, octopamine, and N-methyltyramine, and carotenoids.⁸ ⁹

How much is usually taken?

Usually 1 to 2 grams of dried peel is simmered for 10 to 15 minutes in a cup of water; three cups are drunk daily. As a tincture, 2 to 3 ml (with a weight-to-volume ratio ranging from 1:1 to 1:5) is often recommended for use three times per day. ¹⁰ The purified volatile oil is generally avoided for reasons discussed in the side effects section.

Are there any side effects or interactions?

Bitter orange oil may possibly cause light sensitivity (photosensitivity), especially in fair-skinned individuals.¹¹ Generally this occurs only if the oil is applied directly to the skin and then exposed to bright light; in rare cases it has also been known to occur in people who have taken bitter orange internally. The oil should not be applied topically and anyone who uses it internally should avoid bright light, including tanning booths.

Internal use of the volatile oil of bitter orange is also potentially unsafe and should not be undertaken without expert guidance. Large amounts of orange peel have caused intestinal colic, convulsions, and death in children.¹² The amounts recommended above for internal use should not be exceeded.

One text on Chinese medicine cautions against the use of bitter orange in pregnancy.¹³ This concern is not raised in any other reference, and the American Herbal Products Association classifies the herb as "class 1," a herb that can be safely consumed during pregnancy when used appropriately.¹⁴

Decoctions of bitter orange substantially increased blood levels of cyclosporine in pigs, causing toxicity.¹⁵ Bitter orange also inhibited human cytochrome P450 3A (CYP3A) in the test tube.¹⁶ This is an enzyme that helps the liver get rid of numerous toxins, and strongly affects metabolism of certain drugs. Bitter orange might, therefore, interact with drugs that are metabolized by CYP3A. To be on the safe side, bitter orange should not be combined with prescription medications, unless someone is under the care of an experienced natural medicine clinician.

At the time of writing, there were no well-known drug interactions with bitter orange.

References

1. Martinez M. Las Plantas Medicinales de Mexico. Mexico City: Libreria y Ediciones Botas, 1991.

2. Gonzalez-Ferrara MM. Plantas medicinales del noreste de Mexico. Monterey, Mexico: Grupo Vitro, 1998.

3. Gonzalez-Ferrara MM. Plantas medicinales del noreste de Mexico. Monterey, Mexico: Grupo Vitro, 1998.

4. Bejar E, Bussmann R, Roa C, Sharon D. Herbs of Southern Ecuador: A Field Guide to the Medicinal Plants of Vilcabamba. Spring Valley, CA: LH Press, 2001.

5. Molina GV: Plantas Medicinales en el Pais Vasco. San Sebastian, Spain: Editorial Txertoa, 1999.

6. Bensky D, Gamble A, Kaptchuk T. Chinese Herbal Medicine: Materia Medica, rev. ed. Seattle: Eastland Press, Inc., 1993.

7. Hernandez L, Munoz RA, Miro G, et al. Use of medicinal plants by ambulatory patients in Puerto Rico. Am J Hosp Pharm 1984;41:2060–4.

8. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 1999.

9. Dr. Duke’s Phytochemical and Ethnobotanical Databases. Cited 2003 Jul 11. Available from URL: www.ars-grin.gov, 2002.

10. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 1999.

11. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 1999.

12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1998.

13. Bensky D, Gamble A, Kaptchuk T. Chinese Herbal Medicine: Materia Medica, rev ed. Seattle: Eastland Press, Inc., 1993.

14. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1998.

15. Hou YC, Hsiu SL, Tsao CW, et al. Acute intoxication of cyclosporine caused by coadministration of decoctions of the fruits of Citrus aurantium and the pericarps of Citrus grandis. Planta Med 2000;66:653–5.

16. Guo LQ, Taniguchi M, Chen QY, et al. Inhibitory potential of herbal medicines on human cytochrome P450-mediated oxidation: Properties of umbelliferous or citrus crude drugs and their relative prescriptions. Jpn J Pharmacol 2001;85:399–408.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.

2007-09-01