§§ 577> 578-] 
SAPONIN. 
459 
III.—Saponin—Saponin Substances. 
§ 577. The term “ saponin ” of late years has been applied to a class 
of glucosides which possess the common property of being poisonous, 
and, when dissolved in water, forming solutions which froth on shaking 
like soapsuds. 
The substances which have these properties are not all of the same 
series chemically, but those of the general formula C n H 2n _ 8 O 10 are 
most numerous, and the following is a list :— 
Name. 
Formula. 
Saponin, senegin 
Quillaja-sapotoxin j 
Sapindus-sapotoxin 
r • • • • 
Gypsophila-sapotoxin j 
Agrostemma-sapotoxin J 
Saponin II., digitonin, saporubrin, assamin . 
. c 18 h 28 o 10 . 
Saponin III., quillajic acid, polygalic acid \ 
Hemiari-saponin 
Cyclamin, sarsaparilla-saponin 
• fho-EI^Oio* 
Sarsa-saponin 
• • • • 
• ^22^36 tho - 
Parillin 
• • . a 
• ^26^44^10’ 
Melanthin 
• • • • 
• C 29 H 50 O 10 . 
Possibly also dulcamarin, C 22 H 34 O 10 , and syringin, C 17 H 26 O 10 , may 
belong to this series. 
There are some 150 distinct plants which thus yield saponins; a few of 
these plants are as follows :— Saponaria officinalis , Gypsophila struthium , 
Agrostemma githago (corn cockle), Polygala senega , Monimia polystachia , 
the bark of Quillaja saponaria, and Chrysophyllum glycyphleum. 
The saponin separated from Saponaria and from the corn cockle 
will be here described. 
§ 578. Properties. —Saponin is a white amorphous powder, very 
soluble in water, to which it gives the curious property of frothing just 
like soap solution. To obtain this effect there must be at least 1 mgrm. 
in 1 c.c. of liquid. Saponin is neutral in reaction, it has no odour, but 
causes sneezing if applied to the mucous membrane of the nose ; the 
taste is at first sweet, and then sharp and acrid. The saponins have 
marked haemolytic properties. Saponin is soluble in phenol; it is 
almost entirely insoluble in absolute alcohol, but dissolves in hot alcohol 
of 83°, to separate again nearly completely on cooling. It is precipitated 
by basic lead acetate, and also by baryta water, but in each case it is 
advisable to operate on concentrated solutions. Picric acid, mercuric 
chloride, and alkaloidal “ group reagents ” give no precipitate. When a 
little of the solid substance is treated with “ Nessler ” reagent, there is a 
greenish or yellow colour produced. A drop of strong sulphuric acid, 
mixed with a minute quantity of saponin, strikes slowly a bright red 
colour, which, on heating, deepens to maroon-brown. Nordhausen 
sulphuric acid shows this better and more rapidly. If saponin is boiled 
