1、 Citron pharmacopoeia standard
This product is the dried and mature fruit of the Rutaceae plant Citrus medica L. or citrus Wilson Tanaka. Harvest the fruits when they are ripe in autumn, slice them fresh, and dry them in the sun or at low temperature. Xiangyuan can also be dried in the sun or at low temperature after being cut in whole or in half.
[properties] citric acid is round or oblong in shape, with a diameter of 4-10cm and a thickness of 0.2-0.5cm. The epicarp is yellow or yellowish green in transverse section, with wavy edges and concave oil spots scattered; ; The pulp sac is 10-17 compartments. The central column of longitudinal section is thick. The quality is flexible. It has a light fragrance and tastes slightly sweet and bitter.
Xiangyuan product is spherical, hemispherical or round, with a diameter of 4-7cm. Its surface is dark green or yellowish brown, densely covered with small oil spots and reticular raised coarse wrinkles, with style residue marks and raised rings at the top, and fruit stem residues at the base. It is hard. ; The mesocarp is about 0.5cm thick; the pulp sac is 9-11 chambered, brown or reddish brown, with yellow white seeds occasionally. It smells sweet and tastes sour and bitter.
[identification] take 2G of this product powder, add 30ml of petroleum ether (60 ～ 90 ℃), soak for 1 hour, sonicate for 20 minutes, filter, volatilize the filtrate, and add 1ml of petroleum ether (60 ～ 90 ℃) to dissolve the residue as the test solution. . According to the test of thin-layer chromatography (general rule 0502), suck 5 ～ 10 μ l of each of the above two solutions, respectively dot on the same silica gel G thin-layer plate, use cyclohexane ethyl acetate (5:1) as the developing agent, develop, take out, dry, spray with 3% vanillin sulfuric acid solution, heat until the spots are clear. In the chromatogram of the test sample, the main spot with the same color appears at the position corresponding to the chromatogram of the control medicinal material.
[content determination] xiangyuanzhao was determined by HPLC (general rule 0512).
Chromatographic conditions and system suitability test octadecylsilane bonded silica gel was used as filler; The mobile phase was methanol water glacial acetic acid (30:63:3); The detection wavelength was 284nm. The number of theoretical plates should not be less than 4000 according to the naringin peak.
Preparation of reference solution take an appropriate amount of naringin reference, weigh accurately, add 50% methanol to make a solution containing 30 μ g per 1ml.
Preparation of test solution take about 75mg of powder (passing through No. 5 screen), weigh accurately, place in a corked Erlenmeyer flask, add 25ml of 50% methanol precisely, weigh, heat and reflux for 1 hour, cool, weigh again, use 50% methanol to make up for the lost weight, shake well, filter, take 2ml of continuous filtrate in a fine amount, add 50% methanol to the scale in a 10ml measuring flask, shake well, filter, and take the continuous filtrate.
The determination method is to precisely suck 20 μ l of the reference solution and 20 μ l of the test solution, inject them into the liquid chromatograph, and determine.
The content of naringin (c27h32o14) in this product shall not be less than 2.5% according to the dry product.
Decoction pieces
[processing] if it is not sliced, break it into small pieces; .
[nature, taste and meridian tropism] pungent, bitter, sour, warm. It belongs to the liver, spleen and lung meridians.
[functions and indications] soothe the liver and regulate qi, broaden the middle and dissipate phlegm. It is used for liver and stomach qi stagnation, chest and flank pain, epigastric fullness, vomiting Qi, phlegm and cough.
[usage and dosage] 3 ～ 10g.
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2、 Chemical constituents of citron

1. citric ripe fruit containsHesperidin，Citric acid anhydrous, malic acid, pectin, tannin and vitamin C, etc. The oil content of fruit is 0.3% - 0.7%, the oil content of pericarp is 6.5% - 9%, and the oil contains geranyl acetate,Linalyl acetate(, d-limonene, citral, carvacene,citroptenEt al. Young fruit containsSuccinic acid. seeds containingBerberine，LimoninThe fruit also containsβ - sitosterol，CaroteneAnd triterpene bitter: citrinin.

2. the pericarp of fragrant round fruit contains carotenoids: violaxanthin, lutein epoxide, neoxanthin, β - apo-8-carotene, β - carotene oxide, η - carotene, isoviolaxanthin, luteofuranin, zeaxanthin, cryptoxanthin, hexahydro tomato hydrocarbon and a large amount of vitamin A active substances. Young fruits contain alkaloids:Synephrine ， N-methyltyramine. The leaves contain 43% of the volatile oil, the main components of which are γ - Terpinene, p-cymene, limonene and nerolidol, and also contain a- and β - propene, myrcene, a-carvacene, ocilene, isoterpinene, citronellal, citronellic acid, decanal,Linalool, 4-terpineol, nonanoic acid, a-terpineol, geranyl aldehyde, nerolidol, geranyl acetate, geranyl alcohol, tunicamene, syringalene, and camphene, 3-carene, octanal, heptanal.

3、 Pharmacological effects of citron

The volatile oil contained has a mild stimulatory effect on the gastrointestinal tract, can promote gastrointestinal motility and secretion of digestive fluid, eliminate gas accumulation in the intestine, and has expectorant effect.

1. anti inflammatory effect: hesperidin contained in this product can improve the coagulation of cells in the blood vessels of ocular bulbar conjunctiva and the reduction of capillary resistance caused by vitamin C deficiency in guinea pigs, and can reduce the coagulation of horse blood cells. The survival time of rats can be prolonged by feeding them with thrombogenic feed or atherogenic feed. It can stimulate the growth rate of guinea pigs lacking vitamin C and increase the content of vitamin C in the adrenal gland, spleen and white blood cells of guinea pigs.

2. antiviral effect: before hesperidin is added to vesicular stomatitis virus, mouse fiber cells are pre incubated in 200 μ g/ml hesperidin, which can protect cells from the virus for about 24 hours. Pretreatment of HeLa cells can prevent influenza virus infection. But its antiviral activity can be eliminated by hyaluronidase.

3. other effects: hesperidin can prevent frostbite and inhibit aldehyde reductase of rat lens. Phellodendron can enhance the tension and amplitude of isolated rabbit intestine.