Imperata root
1、 Pharmacopoeia standard of Imperata cylindrica       This product is the dried rhizome of grass Imperata cylindrica beauv.var.major (Nees) c.e.hubb. They were dug in spring and autumn, washed, dried in the sun, removed fibrous roots and membranous leaf sheaths, and bundled into small bundles.
      [properties] this product is long cylindrical, 30 ～ 60cm long, 0.2 ～ 0.4cm in diameter. The surface is yellowish white or light yellow, slightly shiny, with longitudinal wrinkles, obvious nodes, slightly raised, and the length of internodes varies, usually 1.5 ～ 3cm long. It is light, slightly brittle, with white cross-section skin, many cracks, radial arrangement, light yellow middle column, easy to peel off from the skin. It tastes slightly sweet.
      [identification] (1) cross section of this product: 1 column of epidermal cells, square like, small in shape, and some contain siliceous blocks. The lower skin has 1-3 rows of fibers, with thick wall and lignification. The cortex is relatively broad, with more than 10 leaf trace vascular bundles, limited outer tough type, and there are often cracks beside it; . Most of the limited outer tough vascular bundles are scattered in the middle column, and the sheath fibers of the vascular bundle are circular and lignified, and the outer vascular bundle is connected with the fibers to form a ring. The center is often hollow.
      The powder is yellowish white. Epidermal cells are arranged in parallel, and each longitudinal line is often alternately arranged by one long cell and two short cells, and the long cell wall is wavy. The endothelial cells are rectangular, the lateral wall is thickened, the laminae and mural pores are obvious, and there are siliceous blocks on the wall. The fibrous wall of the lower skin is thick, lignified, and often has a transverse septum.
      (2) Take 1g of this product powder, add 20ml of ether, sonicate for 10 minutes, filter, evaporate the filtrate, add 1ml of ether to dissolve the residue as the test solution. Another 1g of the control medicinal material of Imperata cylindrica root was prepared into the control medicinal material solution by the same method. . In the chromatogram of the test sample, spots with the same color appear at the corresponding position of the chromatogram of the control medicinal material.
      [check] moisture   .
      Total ash   .
      [extract] according to the hot leaching method under the determination method of water-soluble extract (general rule 2201), it shall not be less than 24.0%.
      Decoction pieces
      [processing] wash the root of Imperata cylindrica, moisten it slightly, cut it into sections, dry it, and remove the debris.
      This product is a cylindrical segment. The skin is yellowish white or light yellow, slightly shiny, with longitudinal wrinkles, and some slightly raised nodes can be seen. The skin on the cut surface is white, with many cracks, arranged radially, and the middle column is yellowish or hollow, which is easy to peel off from the skin. It tastes slightly sweet.
      [extract] the same as that of medicinal materials, not less than 28.0%.
      [identification] [inspection] is the same as that of medicinal materials.
      Grass root charcoal   Remove the root segment of Imperata arundinacea and stir fry it to scorch Brown according to the charcoal roasting method (general rule 0213).
      This product is shaped like a white grass root, and its surface is dark brown to black, with longitudinal wrinkles. Some light brown slightly uplifted nodes can be seen. It has slightly burnt aroma and bitter taste.
      [extract] the same as that of medicinal materials, not less than 7.0%.
      [identification] (2) the same as that of medicinal materials.
      [nature, taste and meridian tropism] sweet, cold. Return to lung, stomach and bladder channels.
      [functions and indications] cool blood and stop bleeding, clear away heat and diuresis. .
      [usage and dosage] 9 ～ 30g.
      [storage] put it in a dry place.


2、 Chemical constituents of Imperata cylindrica root
The rhizome contains arundoin, cylindrin,Coix（coixol）， Fernenol,Simi azalea（simiarenol）， Isoarborinol, anemonin; It also contains sterols:Stigmasterol（stigmasterol），β - sitosterol（β-sitosterol），Campesterol（camposterol）， Sugars, a large amount of sucrose, glucose and a small amount of fructose, xylose; Simple acids:Citric acidOxalic acid and malic acid.

3、 Pharmacological effects of Imperata cylindrica root
1. diuretic effect: Rhizoma Imperata Decoction and water extract have diuretic effect on normal rabbits. After administration for 5-10 days, the diuretic effect is most obvious, and it is not obvious after about 20 days. However, the dose used, especially the water intake of animals, is not clear, and there is no control group, so further research is needed. Some people also believe that the diuretic effect of Imperata cylindrica root is related to its rich potassium salt.
2. hemostatic effect: Imperata root powder can significantly shorten the recalcification time of rabbit plasma. However, the root of Imperata cylindrica contains more calcium, which may interfere with the experimental results. White grass root powder is sprayed on the bleeding part of the femoral artery of dogs or rabbits and compressed for 1-2 minutes, which has a hemostatic effect. Rhizoma Imperata was used to treat epistaxis clinically.
3. antibacterial effect: Rhizoma Imperata decoction has obvious inhibitory effect on Shigella flexneri and Shigella sonnei dysentery in test tube, but has no effect on Shigella Shigella and Shigella Shua dysentery.
4. effect on myocardial 86Rb uptake: intraperitoneal injection of the water alcohol comprehensive extract of Imperata cylindrica root can increase the myocardial 86Rb uptake in mice.
5. other effects: Coix contained in the root of Imperata cylindrica can inhibit the contraction and metabolism of skeletal muscle. . It has also been reported that the root of Imperata cylindrica has no antipyretic effect.