SAPONINS

SAPONINS (from Latin sapo - soap), plant glycosides distinguished by the following properties: a scratchy, and in large quantities, nauseating taste (hence their use as expectorants); they dissolve (colloidal) in water and alcohol, forming strongly foaming solutions; with cholesterol they give unstable, water-insoluble and weak alcohol-soluble compounds; when such compounds are boiled with toluene or xylene, cholesterol is extracted, while S. remains. S. cause hemolysis and when introduced into the blood produce severe poisoning phenomena. When S. are taken, the body becomes more susceptible to poisons, drugs, and other chemical substances; therefore, when drugs are administered together with S., doses sometimes several dozen times smaller produce the same effect as large doses. This explains the deeper action of many natural substances compared to "purified" active principles. For example, an infusion of foxglove acts much more strongly and reliably than a solution of only the glycosides of foxglove, freed from S; the reason for this phenomenon is seen in the fact that foxglove contains a saponin (digitonin). S. have the property of emulsifying fats; for this purpose, extracts in particular from soapwort root (see) or quillaia have been proposed. Decoctions of plants containing S. are used in the production of halva and as foaming agents in lemonades, in pastries to create artificial "egg foam". Chemically, S. are little studied; it is known that their formula contains a polynuclear skeleton similar to that of cholesterol and bile acids. The general empirical formula of saponins is CnH_2n-sOio. When boiled with dilute acids, they give sugar and the corresponding sapogenin. Discovery of S. The object - a cross-section of the plant, powder, collected foam - is extracted with water. In 5-10 cm³ of extract, a vertically suspended strip of filter paper is placed, which had previously been at a distance of 3 cm from the lower end impregnated with a 1% solution of cholesterol in 96° alcohol and dried. The liquid rises along the strip; S. are retained by the cholesterol zone. This zone is cut off, washed with water, dried, and extracted for 2 hours with boiling xylene. The remaining strip is washed with ether, dried, and placed in blood gelatin. If S. are present, hemolysis occurs, and the medium in this place becomes transparent. Blood gelatin is prepared by dissolving 8 parts of the best gelatin in 92 parts of a 0.9% solution of sodium chloride with the addition of a phosphate buffer (according to Sorensen, to pH = 7.4); the jelly is mixed with 5-10% defibrinated blood at 37-40° (not higher). For quantitative determination, the "Brandt hemolytic index" is determined. From finely ground material, an extract is prepared using 70% alcohol; the extract is exactly neutralized with a solution of caustic soda and (to remove tannins) double the volume of water and drop by drop a solution of egg white is added until a precipitate still forms. The filtered extract is evaporated to dryness; in a small sample, the ash is determined, and then a sample of the dry extract is dissolved in such an amount of water that the content of ash elements is 0.9%. (For practical purposes, it is sufficient to dissolve the sample in a 50-fold amount of water.) The resulting solution is again exactly neutralized, if necessary, with litmus and filtered. In 12 centrifuge tubes, ascending (see table below) amounts of 0.9% solution of NaCl and descending amounts of the test extract are poured with the calculation that in each subsequent tube 20% less extract gets than in the previous one, and the total volume of liquid in each tube is 8 cm³. After shaking each tube to mix the contents, 2 cm³ of fresh blood, defibrinated and diluted 20 times with 0.9% sodium chloride solution (1 cm³ of defibrinated blood and 19 cm³ of 0.9% NaCl solution), are added to all tubes. Tube numbers | Liquids | 2 3 | 4 5 | 6 9 | 10 »| Amount of test liquid in cm³.............. Amount of 0.9% sodium chloride solution in cm³ . . . Amount of defibrinated blood diluted 20 times 7,8 0,2 6,3 1,7 2,0 5,0 3,0 я.п 4,0 4,0 2,0 3,2 4,8 2,0 2,6 5,4 2 0 2,1 5,9 2 0 1,7 6,3 2 0 1,4 6,6 2 0 6,9 1 0 0,9 7,1 0,7| 7,3 i 2,0| All tubes of both series are shaken, ensuring good mixing, and then left undisturbed for 12 hours. After this, their contents are centrifuged and the number of the first tube showing incomplete hemolysis (i.e., a precipitate colored red) is determined. The result is listed in "Brandt hemolytic units". For this purpose, it is calculated how much of the test material corresponds to the extract in the tube preceding the selected number; if this amount is s grams, then the Brandt hemolytic index for this material is expressed by the number-. Similarly, the hemolytic index of lemonades, foams in pastries, etc. is determined; for the extraction of the latter, 60-70% methyl alcohol is used and the extraction is carried out on a water bath with a reflux condenser. In parallel, an experiment is carried out with an extract from soapwort root, which allows an approximate assessment of the content of the latter extract in the tested food products. Similar hemolytic index of Okolov-see Kukol. Preparations of S. have very different strength and even character of action, which to this day hinders the introduction of S. into medical practice. When taken orally in small doses (20 cm³ of a decoction of soapwort root 1:10), S. act irritantly on the mucous membranes, in large doses they can cause vomiting, hemorrhages in the gastrointestinal tract and diarrhea. When introduced into the bloodstream, S. have a very poisonous effect: convulsions, weakening of motor reflexes, paralytic phenomena; in large doses, in addition to nervous phenomena, they also cause cardiac weakness, irritation of the gastrointestinal tract, reaching hemorrhages, vomiting and diarrhea; death from general exhaustion and paralysis of respiration. Locally, there is a decrease in muscle contractility. When very large doses of S. are introduced into the blood, rapid death from paralysis of respiration without pathological-anatomical changes is possible. Cholesterol, by binding with S., detoxifies the latter.- Among S., saponotoxins are distinguished, which have particularly high toxicity (S. of kukol), however, recent studies indicate that saponotoxins may be a mixture of S. with other highly poisonous substances.- Therapeutic use of S. is found in the composition of expectorants (senega, soapwort root, quillaia-see Expectorants); in "pure" form S. are not used, firstly due to the extremely different action, depending on which plant the given S. was obtained from, and the lack of reliable physiological standards and evaluation methods; secondly due to the mentioned danger of increasing the toxicity of other substances taken simultaneously. Commercial S. are usually prepared by extracting the corresponding plants (soapwort root, primrose, senega, quillaia, soapwort, kukol, etc.) with alcohol and precipitating the evaporated alcoholic extract with ether.

I. Obergard. Discovery of saponin in legal cases. The chemical discovery of S. has no solid foundation for itself. The only reliable test is the hemolysis test of blood. The test material is neutralized with magnesium carbonate, in the case of liquids (for example beverages) it is thickened to syrup and extracted with boiling alcohol. The residue after evaporation of the alcoholic extract is extracted with ether to remove fat (if necessary) and dissolved in water, then after adding 0.9% table salt it is tested for hemolysis. If hemolysis is present, the solution is shaken with an ether solution of cholesterol, then heated for several hours at 36°. The ether-free solution ceases to exhibit hemolytic action.