ARECA 



191 



the seed-coat fill with tannin, to which the brown colour is due, and 

 contain alkaloid (Osenbrug, 1894). 



The seed has little odour, but an astringent, slightly bitter taste. 

 The student should observe 

 (a) The shape of the seed, 

 (6) The ruminate endosperm. 



Constituents. Areca nuts contain several alkaloids together with 

 tannin (15 per cent.) and 

 fat (14 per cent.). The 

 most important of the 

 alkaloids, and the one to 

 which the sialogogue and 

 vermifuge properties of the 

 seed are due, is arecoline 

 (methylarecaidine). Other 

 alkaloids are arecaidine, 

 arecaine, guvacine, and 

 choline. 



Arecoline, C 8 H 13 N0 2 (boil- 

 ing-point 220), is a colourless 

 oily liquid yielding crystalli- 

 sable salts. Boiling with hy- 

 drochloric acid converts it into 

 methyl chloride and crystalline 

 arecaidine, from which areco- 

 line can be regenerated. Are- 

 caidine, C 7 H 11 NO 2 , is methyl- 

 tetrahydronicotinic acid and 

 can be synthesised from trigo- 

 nelline. Arecaine is methyl- 

 guvacine and can be prepared 

 by methylating guvacine. 



FIG. 102. Areca nut. a, vertical section of the 

 fruit and seed, showing fibrous pericarp of 

 the former and ruminate albumen of the latter. 

 6, entire seed, natural size. (Bentley and 

 Trimen.) 



Use. The powdered seeds are chiefly used in this country as a vermi- 

 fuge for dogs. 



SEEDS IN LESS FREQUENT USE 



Jequirity Seeds. (Prayer beads) The seeds of Alms precatoriiis, Linne 

 (N.O. Leguminosce), a common Indian and Brazilian shrub. The seeds are 

 sharply characterised by their smooth, glossy surface and bright scarlet colour 

 with a black patch at the hilum ; ovoid or subglobular, 5 to 8 mm. long, 4 to 

 5 mm. broad. They contain a substance known as abrin which is a mixture 

 of two toxic proteins, a paraglobulin which loses its activity at 75 to 80 and 

 a phytalbumose which is destroyed at 85. The action of abrin resembles that of 

 snake venom. An infusion of the seeds has been applied to the eyes for opacities 

 of the cornea but is dangerous ; a paste of the seeds has been used for lupus. 



Abrus root (Indian liquorice) contains a sweet substance resembling but not 

 identical with glycyrrhizin, but it possesses toxic properties. 



