Loquat leaf
1、 Pharmacopoeia standard of loquat leaves       This product is the dried leaves of Eriobotrya japonica (thunb.) lindl., a Rosaceae plant. It can be harvested all year round. When it is 70% or 80% dry, it is bundled into small handfuls and then dried in the sun.
      [character] the product is oblong or obovate, 12-30cm long and 4-9cm wide. It has a sharp apex, a wedge-shaped base, sparse serrations on the edge, and is nearly complete at the base. The upper surface is grayish green, yellowish brown or reddish brown, relatively smooth; The lower surface is densely covered with yellow villi, and the main vein protrudes significantly on the lower surface, and the lateral vein is feathery; The petiole is very short and covered with brown yellow fluff. The leather is brittle and easy to break. .
      [identification] (1) cross section of this product: the upper epidermal cells are oblate and square, covered with thick cuticle; . Palisade tissue consists of 3-4 rows of cells, spongy tissue is loose and contains calcium oxalate crystals and clusters. The vascular bundle of the main vein is tough, nearly annular; Bundle sheath fiber bundles are arranged into discontinuous rings with lignified walls, and the surrounding parenchyma cells contain calcium oxalate crystals, forming crystal fibers; The parenchyma is scattered with mucus cells and contains calcium oxalate crystals.
      (2) . Another 1g of loquat leaf control medicinal material was prepared into the control medicinal material solution by the same method. Then take ursolic acid reference substance and add methanol to make a solution containing 1mg per 1ml as the reference substance solution. Test according to thin-layer chromatography (general rule 0502), suck 1 μ l of each of the above three solutions, dot them on the same silica gel G thin-layer plate, use toluene acetone (5:1) as the developing agent, develop, take out, dry, spray 10% sulfuric acid ethanol solution, and heat at 105 ℃ until the spots are clear. In the chromatogram of the test sample, spots with the same color appear at the corresponding positions of the chromatogram of the control medicinal material and the chromatogram of the control sample.
      [inspection] the moisture content shall not exceed 13.0% (the second method of general rule 0832).
        The total ash content shall not exceed 9.0% (general rule 2302).
      [extract] according to the hot leaching method under the alcohol soluble extract determination method (general rule 2201), 75% ethanol shall be used as solvent, which shall not be less than 18.0%.
      [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 methanol 0.5% ammonium acetate solution (67:12:21); The detection wavelength was 210nm. The number of theoretical plates should not be less than 5000 according to the ursolic acid peak.
      Preparation of reference solution take an appropriate amount of oleanolic acid reference and ursolic acid reference, weigh accurately, and add ethanol to make a mixed solution containing 50 μ g oleanolic acid and 0.2mg ursolic acid per 1ml.
      Preparation of test solution take about 1g of crude powder of the product, weigh it accurately, place it in a conical flask with a stopper, add 50ml of ethanol precisely, weigh it, sonicate (power 250W, frequency 50KHz) for 30 minutes, cool it, weigh it again, add ethanol to make up for the lost weight, shake it well, filter it, and take the filtrate.
      The determination method is to precisely suck 10 μ l of the reference solution and 10 μ l of the test solution, inject them into the liquid chromatograph, and determine.
      The total amount of oleanolic acid (c30h48o3) and ursolic acid (c30h48o3) in this product shall not be less than 0.70% according to the calculation of dry product.
      Decoction pieces
      [processing] the fluff of loquat leaves is removed, sprayed with water, cut into shreds, and dried.
      This product is in the form of silk strips. The surface is grayish green, yellowish brown or reddish brown, relatively smooth. Villi can be seen on the lower surface with prominent main veins. . The breath is slight, and the taste is slightly bitter.
      [inspection] the moisture content is the same as that of medicinal materials, and shall not exceed 10.0%.
      The total ash content is the same as that of medicinal materials, and shall not exceed 7.0%.
      [extract] the same as that of medicinal materials, not less than 16.0%.
      [identification] (except for the transverse section) [content determination] is the same as that of medicinal materials.
      Take the silk of loquat leaf and stir fry it according to the honey roasting method (general rule 0213) until it is not sticky.
      For every 100kg of loquat leaf silk, 20kg of refined honey is used.
      This product is shaped like loquat leaf silk. Its surface is yellowish brown or reddish brown, slightly shiny and slightly viscous. .
      [check]   The moisture content is the same as that of medicinal materials, and shall not exceed 10.0%.
      The total ash content is the same as that of medicinal materials, and shall not exceed 7.0%.
      [identification] (except for the transverse section) [content determination] is the same as that of medicinal materials.
      [nature, taste and meridian tropism] bitter, slightly cold. Return to lung and stomach channels.
      [functions and indications] clear lung, relieve cough, reduce adverse reaction and stop vomiting. For cough due to lung heat, dyspnea and dyspnea, nausea due to stomach heat, fever and thirst.
      [usage and dosage] 6 ～ 10g.
      [storage] put it in a dry place.


2、 Chemical constituents of loquat leaves
Fresh leaves contain 0.045% - 0.108% of volatile oil, the main components of which areNerolidol(nerolidol) and farnesol. Leaf containsAmygdalin(amygdalin)， Tartaric acid,Citric acid anhydrous(citric acid)， Malic acid,oleanolic acid (oleanolic acid)，Ursolic acidUrsolic acid, 2a hydroxyursolic acid, 6a, 19a dihydroxyursolic acid,Hawthorn acid(maslinic acid)， Eriobofuran, loguatifolin a,Hyperin(Hyperoside) and four sesquiterpene glycosides: nerolidol-3-o-a-l-rhamnopyranosyl - (1 → 2) - β - d-glucopyranoside, nerolidol-3-o-a-l-rhamnopyranosyl - (L → 2) - β - d-glucopyranoside, nerolidol-3-o-a-l-rhamnopyranosyl - (1 → 4) - a-l-rhamnopyranosyl - (1 → 2) - β - d-glucopyranoside nopyranosyl- (1-4) - a-l-rhamnopyranosyl- (L → 2) - β - d-glucopyranoside], Nerolidol-3-o-a-l-rhamnopyranosyl - (1 → 4) - a-l-rhamnopyranosyl - (1 → 6) - β - d-glucopyranoside [nerolidol-3-o-a-l-rhamnopyranosyl - (1 → 4) - a-l-rhamnopyranosyl - (L → 6) - β - d-glucopyranoside], nerolidol-3-o - [a-l-rhamnopyranosyl (1 → 4) - a-l-rhamnopyranosyl (1 → 2) -[-a-l-rhamnopyranosyl (1-6)] - β - d-glucopyranoside]

3、 Chemical constituents of loquat leaves
The amygdalin contained in it is decomposed into trace hydrocyanic acid by microbial enzymes in the lower digestive tract. The latter has a sedative effect on the respiratory center, so it has an antiasthmatic and antitussive effect.
. In addition, sesquiterpene glucosides and polyhydroxytriterpene glycosides in the methanol extract of loquat leaves can significantly reduce the urine glucose of hereditary diabetic mice, and the latter can also reduce the blood glucose of normal mice.