Fourth, coumarin glycosides
Coumarin glycosides are glycosides formed by combining coumarin or its derivatives with sugar. This group of glycosides is also widely distributed in the plant kingdom, and has been found in legumes, umbelliferous, solanaceae, rue family, Asteraceae, Xylariaceae and other plants.
Coumarin is an unsaturated lactone formed by dehydration in the ortho-hydroxycinergic acid molecule.
Coumarin glycosides are found in the form or free presence of glycosides in plant bodies, and are found in higher concentrations in flowers, leaves, and fruits, especially in young shoots. In the past, coumarin (also known as coumarin) was only used as a fragrance, but in recent years it has gradually been found to have a wide range of medical uses, such as matricarin has a similar role to vitamin P; hydroxy coumarin has an anti-ultraviolet radiation effect; double coumarin has anticoagulant and antibacterial effects; psoralen coumarin has an antifungal effect; pre-carofuran coumarin has an inhibitory effect on animal experimental tumors. In addition, coumarin glycosides still have antiviral, anesthetic, diuretic, sedative and other effects.
Properties of coumarin:
(1) Soluble in ethanol and boiling water, generally neutral or acidic, can be sublimated. Free coumarin can be distilled with water vapor.
(2) The aqueous solution of hydroxycoumarin glycosides mostly has blue fluorescence, and after adding ammonia water, it becomes yellow fluorescence under ultraviolet light, and the fluorescence is more obvious; the aqueous solution of furan coumarin is blue or yellow-brown fluorescence.
(3) After coumarin or its glycosides are added to the concentrated sulfuric acid, the reaction of orange, pink and dirty green is produced.
(4) Coumarin is a lactone structure, so it also has the characteristics of lactone, coumarin suspension with alkaline, reheating, lactone ring that is broken to form salt, dissolved in water and clear, added acid and cyclic and become turbid.
5. Saponins
Also known as saponin. Dissolved in water into a colloidal solution, after shaking can produce a persistent, soap-like foam-like foam, the molecular structure is in the form of glycosides, so it is called saponins. Saponins are generally white hygroscopic powders or crystals, which are not easy to purify and are easily soluble in water and ethanol. Direct contact with blood has the effect of dissolving red blood cells, but internal use does not have this toxicity.
Saponins are widely present in the Rosaceae family (such as loquat and almond), caryophyllaceae (such as caryophyllus, quercus), platycodonaceae (e.g., platycodon, dang ginseng, sand ginseng), lily family (e.g., Zhimu), potato family (such as pangolin), family Pentagram (such as ginseng, bamboo ginseng), yuanzhi family (such as yuanzhi, melon seed gold, etc.), agave family (agave) and other plants.
Saponins can be hydrolyzed to obtain saponins and sugars, common sugars are glucose, galactose, rhamnose, arabinose, etc., and sometimes see glucuronic acid. Saponins are generally divided into two main categories, namely triene compounds and sterol compounds:
Triterpene saponins, is six isosynthenic di dilute CH2 = C (CH3) - OH = CH3 linkage, with thirty carbon atoms, is a polycyclic compound, mostly on C8 on the -OH group, C17 on the -COOH and other acid groups, and has 1 to 2 double bonds, so this type of saponin is also known as acid saponins.
Steroidal saponins are less distributed in the plant kingdom, mainly in the lily family, diospyraceae, Xuan ginseng family, the structure is very similar to cardiac glycosides, but there is no lactone ring (so there is no cardiotonic effect), there is no acid group in the molecule, so it is also called neutral saponins, because it can be used as a raw material for the synthesis of steroid hormones, in recent years, it has attracted great attention.
In addition to the general versatility of saponins, the main properties of saponins are:
(1) Foaminess - the strong shaking of the aqueous solution can produce persistent foam. Spicy taste, irritation of the mucous membranes, into the nose to cause sneezing, oral promotion of respiratory tract and digestive tract secretion (so saponin-containing herbs, often used as expectorants, such as Yuanzhi).
(2) Hemolytic effect - blood contact with saponins, due to reduced surface tension, blood cells rupture and hemolysis phenomenon (oral no hemolytic effect). A small number of saponins have a weak hemolytic effect. Saponins are extremely toxic to cold-blooded animals such as fish, and a million times thin solution can cause fish to die. Intramuscular injection of saponin aqueous solution is easy to cause tissue necrosis, intravenous injection causes hemolysis, and even produces a systemic reaction, so it is generally not used as an injection.
(3) Solubility - easily soluble in aqueous colloidal solution, insoluble in ether, chloroform, benzene and other organic solvents, aqueous solution into the ammonium sulfate can precipitate saponin precipitation.
(4) Precipitation reaction - trisaponin and neutral lead acetate precipitate, steroidal saponin and carbon lead acetate precipitate, and calcium, magnesium ions can also be combined into salt. Saponins can be combined with cholesterol (cholesterol) to form crystals.
(5) Color reaction - acetic anhydride-acid reaction (Lee-Brinell reaction) is red, purple and green.
6. Nitriles
Nitrile glycosides can be hydrolyzed by enzymes or acids to produce hydroacidic acid (HCN). Most of the plants containing this component belong to the Rosaceae family (such as bitter almonds, prunes, etc.); other cassavas such as euphorbiaceae also contain. Hydrochloric acid is extremely toxic! Therefore, Chinese herbal preparations containing glycosides often need to be measured before they can be applied, and the dose must be strictly controlled.
For more knowledge of Chinese herbal medicine, please pay attention to the dynamics of Liqiang Health Writing.
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