1、 Pharmacopoeia standard of Pueraria lobata
. Excavate in autumn and winter, remove the skin, dry it slightly, cut it in sections or cut it in half longitudinally or cut it into thick pieces obliquely, and dry it.
[properties] this product is cylindrical, spindle like or semi cylindrical, with a length of 12-15cm and a diameter of 4-8cm; some are thick slices cut longitudinally or obliquely, with different sizes. The surface is yellowish white or light brown, and those without peeling are grayish brown. It is heavy, hard and powdery. Light brown concentric rings formed by fibers can be seen on the transverse section, and several longitudinal lines formed by fibers can be seen on the longitudinal section. It tastes slightly sweet.
[identification] (1) the powder of this product is yellowish white. There are many starch granules, rare single granule, spherical, 8-15 μ m in diameter, and the umbilicus is faintly visible; There are many multiple granules, which are composed of more than 2-20 granules. The fibers are mostly in bundles, with thick walls and lignification. Most of the surrounding cells contain calcium oxalate crystals, forming crystal fibers, and the walls of crystal containing cells are lignified and thickened. . The vessels with marginal pits are large, and the pits are arranged very closely.
(2) Take 0.8g of this product powder, add 10ml of methanol, place for 2 hours, filter, evaporate the filtrate, add 0.5ml of methanol to dissolve the residue, and use it as the test solution. In addition, take puerarin reference substance and add methanol to make a solution containing 1mg per 1ml as the reference substance solution. According to the test of thin-layer chromatography (general rule 0502), suck 10 μ l of each of the above two solutions, dot them on the same silica gel G thin-layer plate respectively, make them into strips, use dichloromethane methanol water (7:2.5:0.25) as the developing agent, develop, take out, air dry, and view under the ultraviolet light (365nm). 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.
[inspection] the moisture content shall not exceed 14.0% (the second method of general rule 0832).
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The sulfur dioxide residue shall be determined according to the sulfur dioxide residue determination method (general rule 2331) and shall not exceed 400mg/kg.
[extract] according to the hot leaching method under the alcohol soluble extract determination method (general rule 2201), 70% ethanol shall be used as solvent, which shall not be less than 10.0%.
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Chromatographic conditions and system suitability test octadecylsilane bonded silica gel was used as filler; Methanol water (25:75) was used as mobile phase; The detection wavelength is 250nm. The number of theoretical plates should not be less than 4000 according to the puerarin peak.
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Preparation of test solution take about 0.8g of the powder (passing through No. 3 screen), accurately weigh it, place it in a corked conical flask, precisely add 50ml of 30% ethanol, close the stopper, weigh it, heat and reflux for 30 minutes, cool it, weigh it again, make up the lost weight with 30% ethanol, 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.
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Decoction pieces
[processing] remove impurities, wash, moisten, cut into thick pieces or pieces, and dry.
This product is irregular thick pieces or cubic blocks. The outer surface is yellowish white or light brown. The section is yellowish white. Light brown concentric rings formed by fibers can sometimes be seen on the transverse section, and several longitudinal lines formed by fibers can be seen on the longitudinal section. It is heavy, hard and powdery. It tastes slightly sweet.
[inspection] the moisture content is the same as that of medicinal materials, and shall not exceed 12.0%.
[identification] [inspection] (total ash sulfur dioxide residue) [extract] [content determination] is the same as that of medicinal materials.
. Return to spleen and stomach meridian.
[functions and indications] it can relieve muscle and fever, generate fluid and quench thirst, penetrate rash, raise Yang and stop diarrhea, dredge meridians and activate collaterals, and detoxify alcohol. It is used for exogenous fever and headache, strong pain in the neck and back, thirst, thirst quenching, measles impervious, heat dysentery, diarrhea, dizziness and headache, stroke hemiplegia, chest pain and heartache, alcohol poisoning injury.
[usage and dosage] 10 ～ 15g.
[storage] store in a ventilated and dry place to prevent moths.

2、 Chemical constituents of Pueraria lobata

Pueraria lobata root containsDaidzein，Daidzein，puerarin ，4 '- o-methylpuerarin, daidzein-4 ', 7-diglucoside, daidzein-7 - (6-o-malonyl) - glucoside,Genistein，Formononetin,3 '- hydroxypuerarin，3 '- methoxypuerarin， 4 '- o-glucosylpuerarin, puerarin, puerarin aPuerarinB， Formononetin-7-glucoside,Lupinenone，β - sitosterol, docosanoic acid（docosanoic acid）, tetradecanoic acid, - tetradecanoic acid glyceride,Allantoin， ,Soyasanol a、Soyasanol B , puerarin soap alcohol CPuerarin soap alcoholA and puerarin B methyl esters are triterpenoid saponins of aglycones. Kudzu also containsDaidzein，Daidzein，puerarin andβ - sitosterolThe root of Pueraria lobata containsDaidzein，puerarin ，4 '- o-methylpuerarin，DaidzeinAnd trace daidzein-4,7 '- diglucoside.

3、 Pharmacological action of Pueraria lobata

1. cardiovascular effects:
1.1. effects on cerebral circulation: anesthetized dogs use electromagnetic flowmeter to directly measure cerebral arterial blood flow, and the cerebral blood flow increases by 87.7% - 134% after the carotid artery injection of 0.1-0.5mg/kg total flavonoids of Pueraria lobata, for example, the cerebral blood flow increases by about 20% after the femoral vein injection of 10-30mg/kg total flavonoids; After intramuscular injection of total flavonoids 200mg in hypertensive patients, cerebral blood flow improved, vascular resistance and inflow time decreased in about 53% of patients.

1.2. effects on coronary circulation: the left circumflex coronary artery of anesthetized dogs was inserted with an arterial catheter to measure coronary blood flow. After 1-2mg/kg of total flavonoids was injected through the artery, the blood flow increased by 102% - 120%, and the vascular resistance decreased by 50%. Intravenous injection also had a certain effect; The effect of ethanol extract is similar to that of total flavonoids, which may be related to the fact that Pueraria lobata can treat angina pectoris.

1.3. protective effect on acute myocardial ischemia: intraperitoneal or subcutaneous injection of Pueraria ethanol extract 10g/kg to rats can reduce collateral blood flow during myocardial ischemia caused by intravenous pituitrin, and reduce hemodynamic parameters related to myocardial oxygen consumption, which are beneficial to the treatment of myocardial ischemia.

1.4. effects on cardiac contractility and frequency: Puerarin 0.1, 3 μ mol/l can block the positive chronotropic and negative inotropic effects of isoproterenol on isolated rabbit atrial muscle and guinea pig trachea, and its selectivity for β 1 receptors in atrial muscle is stronger than that for β 2 receptors in tracheal strips. However, it is also believed that puerarin has no effect on α and β receptors, and its mechanism of action is not through adrenergic receptors.

1.5. effect on microcirculation: Puerarin 52mg/kg intravenously injected into mice can alleviate microcirculation disturbance caused by local infusion of epinephrine, such as mesenteric arteriole contraction, blood flow velocity slowing and flow reduction.

2. effect on central nervous system:
2.1. antipyretic effect: Puerarin alcohol extract 2g/kg by gavage has obvious antipyretic effect on rabbits with vaccine fever.

2.2. improving learning and memory: 3.6g/kg of Pueraria alcohol extract or 1.5g/kg of total flavonoids of Pueraria lobata by gavage can resist scopolamine induced memory acquisition impairment and 40% ethanol induced memory reproduction impairment in mice by platform jumping test, and also resist scopolamine reducing acetylcholine content and choline acetyltransferase activity in brain cortex and hippocampus of mice, which may be one of the mechanisms of Pueraria lobata improving learning and memory.

3. smooth muscle spasmolysis: daidzein has spasmolytic effect on isolated intestinal tubes of mice, and can dilate and resist spasm caused by acetylcholine. Its effect is similar to that of papaverine. It is one of the effective ingredients of Pueraria lobata.