This popular widely known fruit goes by a variety of names, creating some possible confusion at times as to which plant one is dealing with. Commonly known as mandarin in much of the world (in Japan it goes by satsuma), the fruit is most often called tangerine in the United States. Generally listed under the botanical name Citrus reticulata, it is also known as C. nobilis, C. madurensis, C. unshiu, C. deliciosa, C. tangerina or C. erythrosa.
A native of Asia, the plant was introduced into Europe early in the nineteenth century. By midcentury, it had spread to the United States, where it was rechristened tangerine. Today, the easily cultivated plant is grown around the Mediterranean, in north Africa, and in both North and South America. Tangerines are generally bigger, rounder, and have more of a yellow-colored skin; mandarins, on the other hand, are smaller, more angular, and deeper orange in color.
The oils produced from the many different cultivars of this plant can vary significantly in chemical composition, reflecting both the particular variety, the country of origin, and the local growing environment.
This small evergreen tree reaches a height of up to about 20 ft (6 m). It has glossy pointed leaves and produces fragrant white flowers. The round fleshy fruit is green when young but ripens to a bright orange or yellow-orange. It was traditionally presented as a gift to the Mandarins of China.
Tangerine peel—called Chen Pi or, sometimes, Ju Hong, meaning red tangerine peel—has a lengthy history of use in traditional Chinese medicine. It is commonly used to treat indigestion, diarrhea, vomiting and other forms of digestive weakness or upset, as well as hiccups and certain types of coughs (specifically, wet coughs involving excessive production of phlegm). It is said to settle, regulate, and normalize the flow of qi (in traditional Chinese medicine, the term for life force), and to break up congestion. In addition, it is believed to enhance the flow of liquids through the body.
The peel of young green tangerines is called Qing Pi and is used to treat pain—particularly in the side and the breast, as well as pain from hernia. In addition, the green peel has been used in the treatment of low blood pressure and (in combination with other herbs) breast inflammation.
C. reticulata is also an ingredient in many traditional Chinese tonics. Among these are the Great Orange Peel Decoction used to treat gout, the Two Cure Decoction used to control morning sickness in pregnant women, and the Five Seed Decoction used to treat male sexual problems, including low sperm count, impotence, and premature ejaculation. A related fertility-and-longevity formula, the Duke of Chou's Centenarian Liquor, is said to have been prescribed for the founder of the Chou Dynasty more than 3,000 years ago. Tangerine peel is also used to make Dr. Huang's Internal Injury Poultice, which is said to promote healing and ease inflammation in connection with pulled muscles, sprains, twisted tendons, and other sports injuries.
The other primary application for C. reticulata is in aromatherapy, where it is used to treat a wide variety of conditions. Some of these uses parallel those in traditional Chinese medicine: for digestive and intestinal complaints (as well as hiccups), to stimulate the lymph system, to eliminate excess fluid, to boost the flow of urine, and to combat obesity. In France and other parts of Europe, it is known particularly as a remedy for children and the elderly—both for digestive problems and to soothe overwrought young minds. One of the gentler citrus oils, tangerine is also used frequently by pregnant women, and is generally said to be a calmative and tranquilizer, helpful in treating nervous tension, emotional stress, depression, and sleep-related difficulties.
Mirroring its use in cosmetics, the oil is also used to treat various skin conditions (such as healing scars, stretch marks, and even acne), and to discourage excessively oily skin.
Tangerine peel is also an ingredient in certain herbal formulas for pets, particularly to treat excess gas.
A 2002 study aimed to test the effect of aromatherapy on pain perception. One of the pleasant odors included orange water, while medicinal odors included vinegar and a dental product. The study found that pleasant odors reduced pain perception in women, but not in men. The study suggested that in clinical settings, smells like disinfectants might promote the perception of pain in some patients.
In traditional Chinese medicine, the dried peel of the fruit is used, often aged (sometimes until it turns black in color) and sometimes even toasted in a wok. Chen Pi means aged peel. A decoction is then made from the peel in combination with other herbs. Both the outermost peel (exocarp) and the inner peel (pericarp) are used for different specific medicinal purposes. C. reticulata is also used to make poultices—a paste of finely powdered herbs that is applied externally to help heal internal injuries. Tangerine peel is also available in pill form.
Aromatherapy, on the other hand, relies on the essential oil extracted from the peel. Depending on the precise type of fruit used, the oil can range from yellow-orange to orange in color, and its chemical properties and uses will also vary. Among the primary chemical constituents of the oil are limonene (as much as 90%), geraniol, citral, and citronella. Several of these (most prominently limonene) have been investigated in the laboratory, showing some potential as cancer inhibitors. Mandarin oil also contains nitrogen compounds such as methyl methyl-anthranilate, which may not be present in tangerine oil.
All of these oils are cold-pressed. In addition, yet another type of mandarin oil is made from the plant's twigs and leaves, using steam distillation. Mandarin oil is widely used in beverages for its intensely orange flavor, as well as in the production of cosmetics and soaps. It blends readily with other oils. Tangerine oil, on the other hand, is not commonly used in cosmetics.
The oil can be applied in a variety of ways: in therapeutic massage, in healing baths, in compresses, or in unguents (healing salves or ointments). It can also be taken in food or drink, put in a diffuser or inhaler, or used in pillows.
Because of the potential confusion over which variety of the plant is called for in a given situation, extra caution is advised to avoid compromising the therapeutic action, introducing unwanted elements, or provoking unintentional interactions. This is particularly true in the context of traditional Chinese medicine in which many different kinds of citrus fruits are used, often for overlapping but not identical purposes. In aromatherapy too, however, care should be taken to determine which oil is required for the desired formula or use.
Occasional allergic reactions to tangerine peel have been noted in the form of prolonged sneezing, cough, chest discomfort, and restlessness.
There are no known interactions with prescription drugs as of 2004.
Lawless, Julia. The Illustrated Encyclopedia of Essential Oils. Rockport, Mass.: Element Books, 1995.
Reid, Daniel. A Handbook of Chinese Healing Herbs. Boston: Shambhala Publications, 1995.
Berger, Joanne M. "Smells Like Relief (Indications)." Internal Medicine News (August 1, 2002): 39.
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