1、 Pharmacopoeia standard of nanbanlangen
This product is the dried rhizome and root of Baphicacanthus cusia (Nees) bremek. Excavate in summer and autumn, remove the aerial stems, wash and dry them in the sun.
; The nodes are swollen, and there are fine roots or stem residues on the nodes; The outer skin is easy to peel off and is blue gray. It is hard and brittle, easy to break, with uneven section, blue gray skin, gray blue to yellowish brown wood, and medullary center. The roots are of different thickness, curved and branched, and the fine roots are slender and flexible. The air is weak and the taste is light.
[identification] (1) cross section of the rhizome of this product: the cork layer is a series of cells, containing brown matter. The cortex is broad, with a number of thick horn cells on the outside; The endothelial layer was obvious; Stone cells are visible. The phloem is narrow and has many phloem fibers. ; The catheter is arranged in single or 2-4 radial directions; Wood rays are broad. Medullary cells are round or polygonal, and stone cells are occasionally seen. The parenchyma cells contained oval corpus callosum.
(2) Take 2G of this product powder, add 20ml of trichloromethane, heat and reflux for 1 hour, filter, and concentrate the filtrate to 2ml as the test solution. In addition, take indigo control and indirubin control and add chloroform to make a mixed solution containing 0.1mg per 1ml as the control solution. According to the test of thin-layer chromatography (general rule 0502), suck 20 μ l of each of the above two solutions, dot them on the same silica gel G thin-layer plate, use petroleum ether (60 ～ 90 ℃) - trichloromethane ethyl acetate (1:8:1) as the developing agent, develop, take out, dry, and inspect immediately. .
[inspection] the moisture content shall not exceed 12.0% (the second method of general rule 0832).
The total ash content shall not exceed 10.0% (general rule 2302).
[extract] according to the hot leaching method under the alcohol soluble extract determination method (general rule 2201), using dilute ethanol as solvent, it shall not be less than 13.0%.
Decoction pieces
[processing] remove impurities, wash, moisten, cut into thick pieces, and dry.
This product is a thick round piece. The outer skin is grayish brown or dark brown. The cut surface is gray blue to light yellowish brown, and there is a kind of white or gray blue spongy pulp in the center. The air is weak and the taste is light.
[identification] (except the cross-sectional surface) [inspection] [extract] is the same as that of medicinal materials.
[nature, taste and meridian tropism] bitter, cold. Homing and stomach meridian.
[functions and indications] it can clear away heat, detoxify, cool blood and eliminate spots. It is used for epidemic febrile diseases, fever, sore throat, mild toxic spots, erysipelas.
[usage and setting] 9 ～ 15g.
[storage] put it in a dry place to prevent mold and moth.

2、 Chemical constituents of Radix Isatidis

Rhizome containsChrysophanol(chrysophanol), ,Indirubin(idirubin), Indigo（indigo),β - sitosterol( β-sitosterol),Lupeol(lupeol),Betulin(betulin),Lupinenone(lupenone)。

3、 Pharmacological effects of Radix Isatidis

It can clear away heat and poison, cool blood and reduce swelling. It is a heat clearing and detoxifying drug of the subordinate of heat clearing drugs. It is mainly used to treat viral and bacterial diseases, such as hepatitis B, chickenpox, tonsillitis, pharyngitis, etc. The water decoction has certain bacteriostatic effect, has inhibitory effect on virus proliferation in vitro, and also has antipyretic, antibacterial, antiviral, antitumor, anti-inflammatory and immune promoting effects.