TANGERINE PEEL (Citrus reticulata)

Latin: Citrus reticulata
Chinese: Chen pi

WHAT IT DOES: Tangerine peel is aromatic, warm and pungent in taste, and warming in action.  It aids digestion, dries up mucus and reduces nausea.

RATING: yellow, due to limitations is usage

SAFETY ISSUES: None known with whole herb. Issues about isolated chemicals found in all citrus products and consumed every day in fruits should not be of concern.

• Dried powder: three to nine grams per day
• Dried peel: one to two teaspoons per day
• Whole fruit: one or more per day while in season, including the juice and the white rind

Doctors use aromatic tangerine peel to dry up mucous in the lungs and stomach.  It helps regulate and strengthen digestion, and is a component of many TCM formulas used to treat diarrhea, nausea, dyspepsia, and cough, especially when accompanied by copious sticky sputum.  Chinese pharmacological studies show that it increases the secretion of gastric juices and relaxes the smooth muscles in the gastrointestinal (GI) tract.  It also stimulates secretion and expectoration in the lungs (reported in Yeung, 1983).  TCM doctors say it moves the qi downward, so it also is useful for treating hiccups and vomiting.  Immature tangerine peel (zhi shi) has similar properties, but shows a stronger unblocking action, and is most often used to treat digestive and mucous problems with constipation.

The herbal concept of heat is a much more palpable experience with tangerines than with oranges.  Both fruits are similar in taste, though tangerines are a bit sweeter.  However, if you eat several tangerines in one sitting, the next day you can often feel the effects of the heat they produce, sometimes causing dryness and a burning sensation in the digestive system and mouth.  This effect does occur nearly as frequently or as powerfully with oranges.

Tangeritin, a bioflavonoid found in tangerine peel, has been shown to strengthen epithelial cells in a manner that inhibits the metastasis of cancer cells (Bracke et al., 1996).  Naturopath Bill Mitchell explained in a lecture that the compound increases the functional integrity of E-cadherin, which is a cell-to-cell adhesive protein found to be deficient in tissue samples of most cancer patients.  Based on these results, we can deduce that tangeritin, and its source, tangerine, might be useful as a cancer preventative.  The reasoning is simple–about 80 percent of breast cancers start in the epithelial tissue lining the breast ducts, and this bioflavonoid makes the tissue tougher and more resistant.  In order to get this benefit you must eat quite a bit of fruit, so the body will have enough left over to store in the tissue.  I suggest eating at least one tangerine pretty much every day while the fruit is in season (but not year-round).

Research Highlights

• An extract of tangeritin (not tangerines per se) blocked the cancer-inhibiting action of tamoxifen in female mice.  It takes quite a large number of tangerines to extract the amount of tangeritin used in the experiments, and mice may not metabolize it in the same way as humans.  However, researchers caution against excessive use of tangerine products during tamoxifen therapy until we know more (Bracke et al., 1999).

• Chinese clinical trials have shown decoctions of tangerine peel and licorice root to be 70% effective within a few days for treatment of mastitis when treatment began in early stages of the disease.  However the treatment was not effective in chronic or purulent cases (reported in Bensky and Gamble, 1993).