«6 



UICTIONAUY OF THE ACTIVE PKl Nciri.ES OV I'LANTS. 



Cascarin), 0,„H„„0,„ (Casselmann), C|.H„0,, (Hesse), C,|H,„0,, (Thorpe 

 and Robinson, 18'.l'2) ; crystallizes in yellow silky needles ; M.P. 22<i", 

 partly sublimable in yellow needles. Acids convert to Emodin and Rbam- 

 nose, C,;H,„0-,. 



Soluble with difficultyincold alcohol, in llJO boiling; also in chloroform, 

 benzene, carbon bisulphide, and very readily in hot glacial acetic acid ; 

 scarcely in ether (the impure substance is soluble), not in water. 



Reactions : 



Alkaline hydrates / ■ , i j i »■ 



, . ■' give purple-coloured solutions. 



Ammonia \ " - ' 



[Tannic acid ) „ i 



[Metallic salts [""P^-^ 

 Metallic oxides produce coloured lakes. 



Concentrated sulphuric acid, emerald changing to purple, then dark 



red ; water reprecipitates. 



(<) EMODIN G. -derivative (Tri-hydroxi-methylantbraquinone), C',,IIi„05 



(Schwabe, Thorpe) ; from Frangulin by action of acids, and naturally in 



various plants, see above; microscopic orange-coloured needles; M.P. 



above "jriC, sublimes slowly at 'IW. 



Soluble in alcohol more readily than Frangulin, also in amyl alcohol, 

 hot benzene, and hot acetic acid ; less difficultly in ether than is the case 

 with Franirulin. Insoluble in water. 



Reactions : 



Alkaline hydrates, cherry red. 

 Alkaline earths, red to brown pp. 

 Lead acetate, neutral or basic, pp. 



Copper sulphate 

 Mercuric chloride 



S I'.io. RHINACANTHUS communis : Ar,„>lhareri: 

 RHINACANTHIN B., CiJIi.Oj ; amorphou.s. 

 Soluble ia alcohol. 



§ nil. RHINANTHUS buccalis ; Alectorolophus hirsutus (the seeds), 

 Melampyrum, Antiirbinum majus (Snapdragon, the leaves). 



RHINANTHIN G., C.j,,H.,.,0._,„ ? (C(,^H5„0j„ ? Pbipson) ; microscopic needles, 

 seen to be prisms when magnified .^UO diameters ; neutral reaction, bitter- 

 sweet taste. Acids convert to Rhinanthogenin, as dark lilue or black 

 flocks, and sugar. 



Soluble in water and alcohol ; not in ether. 



Reactions : 



Alkaline hydrates ) • n „ i »• 



I ■ ■' give yellow solutions. 



Ammonia S 



[Not precipitated by neutral or basic lead acetate.] 



[N'o coloration with ferric chloride.] 



§ U'i. RHUS cotinus (Wig tree); Aii'irarilidcete or Sumach Order. 

 (Rhus coriaria contains Quercetrin ; see Quercus.) 



(a) FUSTIN G., C„Hj„0.,, ; crystallizes in needles; M.P. 218'-219V 

 Acids produce sugar and Fisetin. 



Soluble easily in alcohol, also in hot watsr, but with difficulty in 

 ether. 



Reactions : 



.Soluble in alkaline hydrates. 

 Precipitated by lead acetate (neutral). 

 (/') FISETIN G. -derivative, C,,H„,0„ (J. Herzig), compare Quercetin ; 

 yellow needles from dilute alcohol, or prisms from acetic acid ; becomes 

 anhydrous at 110°, browns at 270' C. ; fluorescent in alcoholic alkaline 

 solution. Yields on hydrolysis Protocatechuic acid, C-H^O^, and Fisetol, 

 CeH.O,. 



Soluble in alcohol, acetone, and acetic ether; with difficulty in ether, 

 chloroform, benzene, or petroleum ether; scarcely in cold water. 

 Reactions : 



Lead acetate to alcoholic solution, yellow pp., soluble in acetic acid. 

 Ferric chloride, greenish-black coloration ; black pp. on adding 



ammonia. 

 Fehlings solution, reduced on warming. 



§ l'.)?>. ROBINIA pseudacacia (Xorth American Locust tree); Legu- 

 tiiiiiosd: The flowers. Investigators : Zwenger and Dronke, Ann, Chem. 

 Pharm., Suppl.. 1, 207. 



ROBININ G., C.,jH.,„0i6-(-.'>iH.,0 ; silky straw-yellow needles; M.P. 105° 

 (anhydrous at 100°); neutral reaction, feebly astringent taste. Acids 

 coiivt-rt to Quercetin (see Quercus and a non-fermentable sugar). 



Soluble iu hot water and hot alcohol, with difficulty in coll water. 

 Insoluble in ether. 



Reactions : 



Alkaline hydrates i . ,, , .■ 



u i give yellow solutions. 

 ,, carbonates i ° •' 



Ammonia, dissolves yellow changing to brown. 



