Madder grass

Rubia cordifolia L., also known as Four Wheel Grass, Lala Vine, Small Blood Activating Grass, and Mountain Climbing Vine, is the root and rhizome of Rubia cordifolia L., a plant in the Rubiaceae family. Rubia is a perennial climbing herb. Born on the rocks of mountain slopes or in grassy areas near ravines. The stem is quadrilateral, with some having spines along the edges. Four leaves are whorled, with one pair being larger and long stalked, ovate or ovate lanceolate in shape; The leaf margin and dorsal vein have active small spikes. Apiform inflorescence grows at the top or axillary; Small flowers, indistinct calyx teeth, green or white corolla. The fruit is fleshy, small in shape, and turns purple black when ripe. Mainly produced in China are Anhui, Hebei, Shaanxi, Henan, and Shandong.

The rhizome of madder is irregularly nodular, with a stem base on the upper side and roots of varying thickness clustered on the lower side. The root is cylindrical in shape, wavy and curved, with a surface that is reddish brown or dark brown, with fine longitudinal lines and a few fine root marks. Crispy texture, flat cross-section, purple red skin, light yellow red wood, slight odor, and slightly bitter taste.

Qiancao root contains various hydroxyl anthraquinone derivatives, such as Alizarin, Purpuro xan, Purpurin, Pseudopurpurin, Munjistin, Rubia, Ruberythric acid, and emodin methyl ether. The active ingredients for whitening were also isolated, including Alizarin I and II, whose aglycone is Alizarin.

Although madder is now commonly used as a traditional Chinese medicine, its history as a dye can be traced back to a very long time ago. The development of dyeing in China is roughly synchronous with the origin of silk fabrics. The widespread dyeing can even be traced back to the development of cave culture. Rubia is the main source of red in ancient silk dyeing. The red color on the clothes of the famous Terra Cotta Warriors is Rubia.

Most of the madder pigments used in modern times are artificially synthesized. The extraction of natural madder pigments is not only complicated, but also the resulting color and hue are not stable enough.

Synthetic madder pigments can be purchased in both chemical reagent stores and pigment stores. According to their color, they are called thearubigins and thearubigins.