GARDENIA:
Key Herb for Dispelling Dampness and Heat Via the Triple Burner
     
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Top Group (left to right): gardenia leaves; gardenia flower, gardenia early stage fruit (green) |
Gardenia (shanzhizi, or simply zhizi) is the fruit of Gardenia jasminoides, one of the frequently used herbs in Chinese medicine. It has an intense bitter taste and a relatively strong cold nature. Yang Yifan has given a detailed description of its qualities and uses (1):
Gardenia is bitter and cold and enters the heart, lung, and triple burner meridians. Bitterness and cold may clear heat and descend fire. Gardenia can gently and slowly direct heat downwards from the upper burner. It can also promote urination and leach out heat from the heart and lung. It can be used for heat accumulation in the chest, irritability, restlessness, sensations of tightness in the chest, and insomnia.
As the triple burner is the passage not only of qi, but also of water, gardenia enters the triple burner meridian and regulates its function. As bitterness can dry dampness and cold can clear heat, this herb can be used to treat damp-heat syndrome in all three burners-for example, infections of the eyes or eczema on the face and neck caused by damp-heat of the upper burner; jaundice due to damp-heat in the middle burner and qi constraint of the liver and gallbladder; or painful urinary dysfunction due to damp-heat in the lower burner which disturbs the function of the bladder.
Gardenia also has the function of cooling the blood and relieving heat-poison. It can be used in different bleeding conditions, such as nosebleed, hematemesis, and blood in the urine. It can also be applied topically for burns.
In the last paragraph of Yang's description, the mention of "different bleeding conditions" mainly refers to heat in the blood, which is said to cause the blood to become erratic and escape the vessels.
Although most herbalists use the whole dried gardenia fruit, in China the herb material is sometimes differentiated by portion of the fruit selected and the processing method. Dr. Jiao Shude explains (2):
In sum, gardenia is used for "all forms of febrile diseases, frenetic movement of hot blood, damp-heat jaundice, and damp-heat strangury (obstructed urination)."
The primary active components of gardenia are iridoid glycosides (mainly geniposide and gardenoside), chlorogenic acid, and ursolic acid. In a water-ethanol commercial extract of the fruits, gardenoside and other iridoids made up 70% of the extract, chlorogenic acid 20%, and ursolic acid 10%. In addition, a complex iridoid glycoside, crocin, is the yellow pigment seen in the fruit. This same pigment is obtained from saffron (see Appendix 1). The gardenia iridoids and chlorogenic acid have been shown to stimulate flow of bile.
In most cases, gardenia is incorporated into large formulas, where it serves to add or reinforce a fire-purging action. The most commonly used formulation with gardenia as a main ingredient is Huanglian Jiedu Tang (Coptis and Scute Combination), in which gardenia is combined with three other herbs that clear heat and dry dampness: coptis, scute, and phellodendron. The formula is indicated for heat in all three burners (sanjiao), to alleviate symptoms such as fever, irritability, insomnia, bleeding, jaundice, and skin eruptions (3). Gardenia is "directed" to resolve heat in a specific burner by combination with certain herbs. As typical examples: for the lower burner, rhubarb and/or moutan; for the middle burner, scute and/or gentiana; for the upper burner, soja and/or coptis. A small formula with gardenia and rhubarb, Yinchenhao Tang, is mentioned in Appendix 2.
Crocin extract is the trade term for the yellow, water-soluble food colorant obtained from Gardenia jasminoides (commonly called "cape jasmine") and from Crocus sativus (saffron). The extracts are not used interchangeably in all applications since saffron is valued as much for its aroma and flavor as for its coloring properties and, moreover, it is the world's most expensive spice/colorant, while gardenia extract is relatively inexpensive. The following table compares the two sources (4):
| Quality for Comparison | Saffron | Gardenia |
| Usage | For flavoring and imparting a yellow color to foods. | Yellow food colorant. The extract lacks the flavor components of saffron that are desired. |
| Common name for processed product | Saffron extract or crocin extract. | Crocin extract; gardenia extract. |
| Raw material source | Stigmas of a crocus flower; mainly cultivated. | Fruits of a shrub; mainly cultivated. |
| Botanical source | Crocus sativus (Iridaceae). | Gardenia jasminoide (Rubiaceae). |
| Synonyms for botanical source | No others | Gardenia florida; Gardenia grandiflora; Gardenia augusta. |
| Common names for botanical source | Saffron (English); safran (French and German); azafran (Spanish); fanhunghua (Chinese); Za'faran (Arabic). | Cape Jasmine, garden gardenia; bunga cina (Malaysia); ceplok piring (Indonesia); rosal (the Philippines); phut cheen (Thailand). |
| Distribution | Indigenous to Greece, Turkey and Iran; now widely cultivated across temperature zones from Europe to China and in the Americas. | Indigenous to southern China and Japan; widely cultivated elsewhere, especially in Southeast Asia. |
| International Trade | About 50 tons/year. | Unquantified, but relatively small. |
| Major exporters | Spain and Iran rank first; India ranks second. | China. |
| Major importers | Gulf and Middle East states. | Far East and Southeast Asian countries. |
| Availability of reliable published information | Good. | Poor. |
Crocin is the gentiobiose form of the carotenoid crocetin. In addition to the crocins, cape jasmine fruits contain iridoid and flavonoid pigments. The aroma of saffron arises from a volatile aldehyde, safranal, which is produced during processing from picrocrocin; the latter is responsible for the bitter taste of saffron.
Cape jasmine is an evergreen shrub that originates from southern China and Japan. It is now widely cultivated in the tropics and sub-tropics, particularly in Southeast Asia both as a garden ornamental and as a source of a yellow food colorant. The pigments are contained in the fruit that is used in the Far East, either directly or after drying, in a wide range of dishes and as a medicinal decoction with other herbs. In recent years, usage of the extract has developed in the processed food industries in Western Europe as a less expensive colorant substitute for saffron in applications where the latter's flavor is not required. It is usually sold under the name of "crocin extract." Typical dosage levels of the extract in confectionery and bakery products range from 0.05 to 0.1%, while fish products in brine may contain up to 1.5%. Geniposide from gardenia can be reduced to the colorless aglycone genipin which, in turn can be transformed into a blue color, used as a dye, by simple chemical transformation using methylamine
Yinchenhao Tang (Capillaris Combination) is a purgative that has been researched extensively because of its potent bile-purging activity. Its modern formulation is 18-30 grams capillaris (yinchenhao; Artemisia capillaris), 12-15 grams gardenia, and 6-9 grams rhubarb. Its main indication is clearing damp-heat in cases of biliary obstruction, as may occur with acute hepatitis, cholecystitis, and gallstones.
Gardenia is considered an important contributor to the effects of this formula, with gardenoside as one of the potent biliary stimulants. It has been shown that gardenoside is mostly present in the interior of the gardenia fruits and that if gardenia is decocted intact, the resulting extraction of gardenoside is limited. Therefore, gardenia shells should be crushed prior to decocting (4).
Yinchenhao Tang is classified in modern Chinese medicine guides as a formula for clearing damp accumulation and promoting urination. The Advanced Textbook of Traditional Chinese Medicine explains (5):
This prescription is indicated for cases of jaundice due to the accumulation of dampness-heat in the interior. Internal accumulated dampness-heat disrupts qi activity, causing dysuria, abdominal fullness, thirst, yellow and greasy tongue coating, and smooth and rapid pulse. In the prescription, capillaris is a special agent for relieving jaundice, and is used in a larger dosage as the chief ingredient to eliminate heat and dampness. Gardenia serves as the adjuvant ingredient to purge dampness-heat from the triple burner through urination. Rhubarb is applied as the assistant ingredient to purge accumulated heat and promote bowel movements. The three drugs together eliminate dampness-heat through urination and defecation, thus relieving jaundice.
Jaundice is not a condition frequently presented to modern practitioners in the West, but accumulation of damp-heat is commonly reported. In such cases, capillaris is less important as a component of treatment, and can be given in lower dosage, while gardenia remains a central herb for dispelling both dampness and heat.
September 2003