Natural indigo (Qingdai)
Baphicacanthus cusia (Acanthaceae)
Pharmaceutical Name: Indigo Naturalis
Botanical Name: A blue powder prepared from: 1. Baphicacanthus cusia (Acanthaceae); 2. Indigofera suffruticosa Mill. (Leguminosae); 3. Polygonum tinctorium Ait. (Polygonaceae); 4. Isatis indigoticaFort. (Cruciferae)
Common Name: Natural indigo
Source of Earliest Record: Yaoxing Lun.
Part Used & Method for Pharmaceutical Preparations: The combination of pigments from Baphicacanthus cusia, Indigofera suffruticosa, Polygonum tinctorium and Isatis tinctoria is prepared and dried into a blue powder.
Properties & Taste: Salty and cold.
Meridians: Liver, lung and stomach.
Functions: 1. To clear heat and release toxins; 2. To cool blood and reduce swelling
Indications & Combinations:
1. Eruptions due to toxic heat in the blood. Natural indigo (Qingdai) is used with Gypsum (Shigao) and Fresh rehmannia root (Shengdihuang) in the formula Qingdai Shigao Tang.
2. Hemorrhagic disease due to extravasation of the blood by heat manifested as vomiting of blood, epistaxis and cough with blood and sputum. Natural indigo (Qingdai) is used with Biota tops (Cebaiye) and Imperata rhizome (Baimaogen).
3. Infantile convulsions due to high fever. Natural indigo (Qingdai) is used with Ox gallstone (Niuhuang) and Uncaria stem (Gouteng) in the formula Liang Jing Wan.
4. Heat in the lungs manifested as cough, asthma and cough with thick yellow sputum. Natural indigo (Qingdai) is used with Trichosanthes fruit (Gualou), Tendrilled fritillary bulb (Chuanbeimu) and Costazia bone (Haifushi) in the formula Qingdai Haishi Wan.
5. Acute mumps, boils and carbuncles.Natural indigo (Qingdai) is used with Scrophularia (Xuanshen), Honeysuckle flower (Jinyinhua) and Forsythia fruit (Lianqiao).
6. For ulcers in the mouth, mumps, and pharyngitis, it is used internally or topically. It can be used alone or with Radix Scrophulariae (Xuan Shen), Flos Lonicerae (Jin Yin Hua), and Fructus Forsythiae Suspensae (Lian Qiao).
Dosage: 1.5-3 g used as pills or powder; cannot be used in decoction. It can also be mixed with water for external use.
Cautions & Contraindications: This substance is contraindicated during a cold in the stomach.
Comparision:Indigo Naturalis (Qing Dai) and Folium Isatidis(Da Qing Ye): they have a similar function, but the former is more effective in clearing Heat from Blood and checking Endogenous Wind.
