Equisetum
1、       This product is the dry aboveground part of Equisetum hyemale L., a plant of Equisetum family. Harvest in summer and autumn, remove impurities, and dry in the sun or in the shade.
      [properties] the product is long tubular, unbranched, 40 ～ 60cm long, 0.2 ～ 0.7cm in diameter. The surface is grayish green or yellowish green, with 18 ～ 30 longitudinal edges, and most of the small and bright warty protrusions on the edges; The nodes are obvious, and the internode is 2.5 ~ 9cm long. The nodes are covered with tubular scale leaves, and the base of leaf sheath and sheath teeth are black brown, with light brown yellow in the middle. It is light, brittle, easy to break, hollow in section, and surrounded by many small circular cavities. It has slight air, sweet and light taste, slightly astringent, and feels like sand when chewing.
      [identification] (1) cross section of the stem of this product: 1 column of epidermal cells, covered with cuticle. . There are 2 transparent siliceous warty protrusions on the ridge and 2 concave pores in the groove. The cortex is a parenchyma with long columnar or quasi circular cells, and the thick walled tissue located in the inner side of the ridge extends into the cortical parenchyma as a wedge. The thick walled tissue in the groove has only 1-2 layers of cells, and there is a cavity below the groove. There are two inner and outer rows of endothelial layer, the outer row is wavy ring, and the inner row is circular ring, both of which can be seen with obvious Kjeldahl points. The outer tough type of vascular bundle is located between two rows of endothelial layers opposite to the longitudinal edge, and there is a bundle of lumen inside the vascular bundle. The parenchymal cells of the medulla oblate, with the central medullary cavity.
      (2) Take 1g of the product powder, add 25ml of 75% methanol and 1ml of hydrochloric acid, heat and hydrolyze for 1 hour, filter, evaporate the filtrate, add 10ml of water to dissolve the residue, extract twice with ethyl acetate, 10ml each time, combine the ethyl acetate solution, evaporate to dryness, add 1ml of methanol to dissolve the residue, and use it as the test solution. . Test according to thin-layer chromatography (general rule 0502), suck 5 μ l of the test solution and 2 μ l of the control solution, dot them on the same silica gel G thin-layer plate, use cyclohexane ethyl acetate formic acid (8:4:0.4) as the developing agent, develop, take out, dry, spray 5% aluminum trichloride ethanol solution, and immediately put them under the UV light (365nm) for inspection. In the chromatogram of the test sample, fluorescent spots of the same color appear at the corresponding positions of the chromatogram of the control sample.
      [check] moisture   .
      [extract] according to the hot leaching method under the determination method of alcohol soluble extract (general rule 2201), the use of ethanol as solvent shall not be less than 5.0%.
      [content determination] determine according to HPLC (general rule 0512).
      Chromatographic conditions and system suitability test   Octadecylsilane bonded silica gel was used as filler; The mobile phase was acetonitrile-0.4% phosphoric acid solution (50:50); The detection wavelength was 365nm. The number of theoretical plates should not be less than 3000 according to the kaempferol peak.
      Preparation of reference solution   Take an appropriate amount of kaempferol reference substance, accurately weigh it, add 75% methanol to make a solution containing 20 μ g per 1ml.
      Preparation of test solution   Take about 0.75g of this product powder (passing through No. 3 screen), weigh accurately, place it in a corked conical flask, add 50ml of 75% methanol precisely, close the stopper, weigh the weight, heat and reflux for 1 hour, cool it, then weigh the weight, use 75% methanol to make up the weight lost, shake it well, filter it, accurately measure 20ml of the secondary filtrate, add 5ml of hydrochloric acid, heat and hydrolyze it in a water bath for 1 hour, cool it, transfer it to a 50ml volumetric flask, add 75% methanol to the scale, shake it well, filter it, and take the secondary 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.
      The content of kaempferol (c15h10o6) in this product shall not be less than 0.20% calculated as dry product.
      Decoction pieces
      [processing] remove the withered stems and residual roots, spray water, moisten slightly, cut into sections, and dry.
      . The surface is grayish green or yellowish green, with 18-30 longitudinal edges, and there are many small bright wart like protrusions on the edges; The nodes are obvious, and there are tubular scale leaves on the nodes. The base of leaf sheath and sheath teeth are black brown, and the middle is light brown yellow. The cut surface is hollow, and there are many small circular cavities around it. It has slight air, sweet and light taste, slightly astringent, and feels like sand when chewing.
      [identification], [inspection], [extract], [content determination] are the same as those of medicinal materials.
      [nature, taste and meridian tropism] sweet, bitter and flat. Return to lung and liver channels.
      [functions and indications] evacuate the wind and heat, brighten the eyes and remove the clouds. It is used to make the eyes red in the wind heat, shed tears in the wind, and make the eyes cloudy.
      [usage and dosage] 3 ～ 9g.
      [storage] put it in a dry place.


2、
The aerial part contains volatile oil, of which the organic acid isSuccinic acid（succinic acid），Fumarate（fumaric acid）， Glutaric acid methyl ester,P-hydroxybenzoic acid（p-hydroxybenzoic acid）， M-hydroxybenzoic acid,Ferulic acid（ferulic acid），Vanillic acid（vanillic acid），caffeic acid（caffeic acid）， . , Gossypetin-3- β -d- (2-O β -d-glucopyranosidoglucopyranoside) -8- β -d-glucopyranoside]. It also contains alkaloids: palustrine, and tracenicotine（nicotine），Vanillin（vanillin）， P-hydroxybenzaldehyde, glucose, fructose, phosphorus, silicon, tannins, saponins, etc.

3、 Pharmacological action of Equisetum
. The whole plant of the same genus e.arvensel has diuretic effect; It has been used to treat diabetes in clinic, but animal experiments have not confirmed it. Livestock eating Equisetum and Equisetum plants can cause poisoning, with symptoms of limb weakness, ataxia, difficulty turning, tremor and muscle rigidity when livestock are moving, weak and frequent pulse, cold limbs, blood chemical analysis shows that vitamin B is deficient, and a large amount of vitamin B can detoxify.
1. cardiovascular effects: Equisetum alcohol extract can increase the coronary flow of isolated guinea pig heart. Intravenous injection of 0.2ml/kg (100% extract) has a certain antagonism and buffering effect on the T wave elevation and heart rate slowing caused by pituitrin. Equisetum alcohol extract 10-15g/kg intraperitoneal injection or 20g/kg duodenal administration has a lasting hypotensive effect on anesthetized cats. The intensity and duration of hypotension were related to the dose. . It can obviously dilate the isolated blood vessels of rabbits.
2. other effects: ferulic acid can inhibit platelet aggregation and release. It has sedative and anticonvulsant effects in animal experiments. Its median lethal dose (mg/kg) is 946 in mice by intraperitoneal injection and 3000 in rats by gavage. . Blood analysis showed vitamin B deficiency, and treatment with a large amount of vitamin B could return to normal.