Qing Dai (QD) is a unique compound extracted from the pigments of plants such as Indigofera tinctoria, Strobilanbthes cusia, O Kuntze, and Polygonum tinctoium Lour.
Today, Qing Dai is commonly used for medical purposes, but the extract was historically known for its vibrant indigo pigment, highly prized since the time of the Persian Kingdom. Ancient Persians, Greeks, and Romans used the dye for luxurious fabrics and glamorous eye make-up. At the time, indigo dye was so valuable it was known as ‘blue gold’.
Indigo naturalis first reached China via the Silk Road trading route. There, it found new life in the hands of ancient Chinese physicians who began using it as herbal medicine. They’d discovered the mixture could reduce fever, and detoxify and cool the blood. It was thus utilized for heat-clearing, to purify the liver, alleviate pain and reduce inflammation. Indigo naturalis has been in continual use ever since.
Now known as Qing Dai (QD), the compound is used in China to treat infectious diseases, skin diseases, tumors, and inflammatory bowel disease. It’s drawn considerable clinical interest, as researchers attempt to understand its pharmacology, mechanisms, and its potential as a treatment for a range of modern diseases.
So far, QD has been clinically confirmed to contain anti-inflammatory, antioxidant, antibacterial, antiviral, and immunomodulatory properties. Of note, the compound has shown a “good clinical effect” on psoriasis, leukemia, and ulcerative colitis. It should be noted that despite the extremely promising results of QD, an understanding of its correct, effective and safe use is not yet widespread.