licorice
1、 Pharmacopoeia standard of liquorice       This product is the dried roots and rhizomes of Glycyrrhiza uralensis fisch., Glycyrrhiza inflata bat., or Glycyrrhiza glabra L., a leguminous plant. Excavate in spring and autumn, remove fibrous roots and dry them in the sun.
      [character] the root of Glycyrrhiza uralensis Fisch is cylindrical, 25-100cm long, 0.6-3.5cm in diameter. The outer skin is not uniform in tightness. The surface is reddish brown or grayish brown, with significant longitudinal wrinkles, furrows, lenticels and sparse fine root marks. The texture is solid, and the section is slightly fibrous, yellowish white, powdery, with obvious cambium rings, radial rays, and some cracks. . It tastes sweet and special.
      Glycyrrhiza inflata   The roots and rhizomes have thick wood, some branches, rough skin, and are mostly grayish brown or grayish brown. . The rhizome and adventitious buds are numerous and thick.
      Glycyrrhiza glabra   .
      [identification] (1) cross section of this product: the cork layer is a series of brown cells. The inner layer of the bolt is narrow. Phloem rays are broad, curved, and often show cracks; The fibers are mostly bunched, non lignified or slightly lignified, and the surrounding parenchyma cells often contain calcium oxalate crystals; . The intrafascicular cambium is obvious. Xylem ray width 3-5 rows of cells; There are many catheters with a diameter of about 160 μ m; The wood fibers are in bundles, and the surrounding parenchyma cells also contain calcium oxalate crystals. The root center is unmyelinated; The rhizome center is myelinated.
      The powder is light brown yellow. The fibers are in bundles, with a diameter of 8-14 μ m, a thick wall, microlignified, and the surrounding parenchymal cells contain calcium oxalate crystals, forming crystalline fibers. Calcium oxalate crystals are common. The marginal foramen ducts are larger, and the reticulate ducts are rare. Cork cells are reddish brown, polygonal, and microlignified.
      (2) Take 1g of the product powder, add 40ml of ether, heat and reflux for 1 hour, filter, discard the ether solution, add 30ml of methanol to the drug residue, heat and reflux for 1 hour, filter, evaporate the filtrate, add 40ml of water to dissolve the residue, extract three times with n-butanol, 20ml each time, combine the n-butanol solution, wash three times with water, discard the water solution, evaporate the n-butanol solution, add 5ml of methanol to dissolve the residue, and use it as the test solution. . Then take monoammonium glycyrrhizinate reference substance and add methanol to make a solution containing 2mg per 1ml as the reference solution. According to the test of thin-layer chromatography (general rule 0502), suck 1-2 μ l of each of the above three solutions, dot them on the same silica gel G thin-layer plate prepared with 1% sodium hydroxide solution, use ethyl acetate formic acid glacial acetic acid water (15:1:1:2) as the developing agent, develop, take out, air dry, spray 10% sulfuric acid ethanol solution, heat at 105 ℃ until the spots develop clearly, and check under the ultraviolet light (365nm). In the chromatogram of the test sample, fluorescent spots of the same color appear at the corresponding position of the chromatogram of the control medicinal material; On the position corresponding to the chromatogram of the reference substance, the same orange yellow fluorescent spots appear.
      [check] moisture   .
      Total ash   .
      Acid insoluble ash   Not more than 2.0% (general rule 2302).
      Heavy metals and harmful elements   According to the determination method of lead, cadmium, arsenic, mercury and copper (general rule 2321 atomic absorption spectrophotometry or inductively coupled plasma mass spectrometry), lead shall not exceed 5mg/kg; Cadmium shall not exceed 0.3mg/kg; Arsenic shall not exceed 2mg/kg; Mercury shall not exceed 0.2mg/kg; .
      Organochlorine pesticide residues   Determine according to the pesticide residue determination method (general rule 2341 determination of organochlorine pesticide residues - Method 1).
      The total BHC content (the sum of α -bhc, β -bhc, γ -bhc and δ -bhc) shall not exceed 0.2mg/kg; Total DDT (the sum of pp'-dde, pp'-ddd, op'-ddt and pp'-ddt) shall not exceed 0.2mg/kg; Pentachloronitrobenzene shall not exceed 0.1mg/kg.
      [content determination] determine according to HPLC (general rule 0512).
      Chromatographic conditions and system suitability test   ; Acetonitrile was used as mobile phase a, and 0.05% phosphoric acid solution was used as mobile phase B. gradient elution was performed according to the following table; The detection wavelength was 237nm. The number of theoretical plates should not be less than 5000 according to the liquiritin peak.
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    0～8        19           81
    8～35       19→50       81→50
    35～36      50→100      50→0
    36～40      100→19      0→81
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      Preparation of reference solution   .
      Preparation of test solution   Take about 0.2g of this product powder (passing through No. 3 screen), weigh it precisely, place it in a corked conical flask, add 100ml of 70% ethanol precisely, close the stopper, weigh it, sonicate (power 250W, frequency 40KHz) for 30 minutes, cool it, weigh it again, make up the weight lost with 70% ethanol, shake it well, filter it, and take the filtrate.
      Assay   Precisely suck 10 μ l of the reference solution and 10 μ l of the test solution respectively, inject them into the liquid chromatograph, and determine.
      According to the calculation of dry product, the content of liquiritin (c21h22o9) shall not be less than 0.50%, and glycyrrhizic acid (c42h62o16) shall not be less than 2.0%.
      Decoction pieces
      [processing] remove impurities, wash, moisten, cut into thick pieces, and dry.
      ; This product is a thick round or oval shaped piece. The outer skin is reddish brown or grayish brown, with longitudinal wrinkles. The cut surface is slightly fibrous, the center is yellowish white, with obvious radial texture and cambium ring. It is solid and powdery. It tastes sweet and special.
      [check] total ash   No more than 5.0% for the same medicinal materials.
      [content determination] the content of liquiritin (c21h22o9) shall not be less than 0.45% and glycyrrhizic acid (c42h62o16) shall not be less than 1.8% in the same medicinal material.
      [identification] (except for the cross section) [inspection] (moisture, heavy metals and harmful elements) are the same as those of medicinal materials.
      [nature, taste and meridian tropism] sweet and smooth. Return to heart, lung, spleen and stomach meridian.
      [functions and indications] tonify the spleen and Qi, clear away heat and detoxify, expectorant and cough, relieve pain, and reconcile various drugs. It is used for spleen and stomach weakness, fatigue, palpitation and shortness of breath, cough and phlegm, abdominal and limb contracture and pain, carbuncle, swelling and sores, to relieve drug toxicity and intensity.
      [usage and dosage] 2 ～ 10g.
      [note] it should not be used with seaweed, Beijing euphorbia, red Euphorbia, kansui and Daphne genkwa.
      [storage] store in a ventilated and dry place to prevent moths.


2、 Chemical constituents of Glycyrrhiza uralensis
Roots and rhizomes contain glycyrrhizin (i.eglycyrrhizic acidglycyrrhinicacid,C42H62O16）6～14％， It is a sweet ingredient of licorice and a triterpene saponin.glycyrrhizic acidHydrolyze to produce a moleculeGlycyrrhetinic acid(glycyrrheticacid, c30h46o4) and two molecules of glucuronic acid (c6h10o7). And contained a small amount of glycyrrhizin (i.eliquiritin liquiritin,C21H22O9, It is a flavanol flavanone glycoside, and its aglycone name isLiquiritigeninLiquiritigenin, c15h12o4 and glycyrrhizin, isoliquiritin, c21h24o9, dihydroxyglycyrrheticacid (c30h46o5)Glycyrrhizin(licoricidin, c25h32o5, namely 3 ', 6-diisopentene-2', 4 ', 5-trihydroxyisoxanthane)Glycyrrhizin（glycyrol,C21H18O6）、 5-0-methylglycyrrhizol (c22h20o6), ISO glycyrrhizol (c21h18o6), in addition, it also containsD-Mannitol（D-mannite）、 .

3、 Pharmacological action of liquorice
1. detoxification: glycyrrhizin or its calcium salt has a strong detoxification effect, has a strong detoxification effect on diphtheria toxin and tetanus toxin, and also has detoxification effect on some allergic diseases, animal experimental hepatitis, tetrodotoxin and snake venom. Its detoxification mechanism may be multifaceted. Through physical and chemical precipitation, adsorption and combination, strengthening the detoxification function of the liver and glucuronic acid, the hydrolysate of glycyrrhizin, are also effective ingredients for detoxification.

2. anti inflammatory and anti allergic reactions: glycyrrhetinic acid can inhibit cotton ball granuloma, formaldehyde edema, tuberculin reaction and subcutaneous granulosa cystic inflammation in rats. Ammonium glycyrrhizinate and sodium glycyrrhetinic acid can effectively affect the exudative and proliferative stages of subcutaneous granulation cystic inflammation, and their action intensity is weaker than or close to cortisone. Among the anti-inflammatory effects of various preparations of glycyrrhizic acid, succinate has higher activity, but it is also toxic. The principle of anti-inflammatory and anti allergic reaction of Glycyrrhiza uralensis has not been fully clarified.

3. licorice has expectorant effect, can promote the secretion of throat and bronchus, and make sputum easy to come out.

4. the derivatives of glycyrrhetinic acid have significant antitussive effects on experimental cough in guinea pigs and cats.

5. various preparations of licorice have obvious inhibitory effects on experimental gastric ulcer in rats. The water extract of Glycyrrhiza uralensis Fisch has the effect of protecting gastric mucosa and treating gastric ulcer. According to the observation of the clinical and pharmacological research laboratory, the water extract of Glycyrrhiza uralensis can increase the "hexosamine" component of gastric mucosal cells, so that the gastric mucosa is not damaged.

6. effect on gastric secretion: after gavage, liquorice flow extract can adsorb gastric acid, so it can reduce the concentration of gastric acid, but it can also play a role after absorption. .

7. antispasmodic: Licorice Decoction and flow extract have inhibitory effects on isolated animal intestinal tubes, and have antispasmodic effects on intestinal spasm caused by acetylcholine, barium chloride, histamine, etc. Glycyrrhiza uralensis has a relaxing effect on the isolated intestine and in vivo stomach of animals.

8. Glycyrrhiza uralensis Fisch. For experimental liver injury in animals, its liver degeneration and necrosis were significantly reduced, the contents of hepatic glycogen and ribonucleic acid accumulated in hepatocytes were largely restored or close to normal, and the activity of serum alanine aminotransferase was significantly decreased, indicating that Glycyrrhiza uralensis Fisch. Has the effect of anti liver injury.

9. adrenocorticotropic hormone like effect: Glycyrrhiza uralensis can reduce urine output and sodium excretion, increase potassium excretion, increase blood sodium, decrease blood calcium, and atrophy of adrenal cortical zona. Glycyrrhiza uralensis can increase the excretion of free 17 hydroxycorticosteroids in urine, and reduce the binding type. Small doses show thymus atrophy, adrenal weight increases, fascicular layer amplitude widens, and adrenal vitamin C content decreases. Licorice can significantly enhance and prolong the effect of cortisone. According to the principle of licorice producing adrenocortical hormone like effect, some people believe that the chemical structure of glycyrrhetinic acid is similar to that of adrenocortical hormone, and the effect is also similar, which is a direct effect; Some people also believe that it is an indirect effect, that is, glycyrrhetinic acid inhibits the destruction of adrenocortical sterols in the body, so the content of corticosteroids in the blood increases correspondingly, showing a more obvious adrenocortical hormone like effect.

10. Glycyrrhiza uralensis has the effect of antagonizing acetylcholine and enhancing the cardiotonic effect of epinephrine.

11. anticancer: glycyrrhetinic acid can inhibit experimental myeloma and ascites hepatoma in rats. It can inhibit Ehrlich ascites cancer in mice.

12. the combination of licorice and Daphne genkwa has the opposite effect: the toxicity of the two co soaking groups is significantly higher than that of the sub soaking group. When Daphne genkwa and licorice are used together, the diuretic and purgative effects are inhibited, and the toxicity of licorice can be enhanced.