BY JAME.S 31. PETRIE. 347 



Tlie pharmacological properties were compared with those of E. guineetme 

 in the literature quoted, being the investigationis of Lauder Brunton, Harnack, 

 Jlen-k, and Dr. Dale of the Wellcome Research Laboratories. The alkaloids of 

 the two species of Eri/throphloeum have the same action: that is, the active 

 principle of the Australian E. Laboucherii is the alkaloid erythrophleine. 



It is remarkable that a group of properties hitherto known to belong only 

 to certain glucosides should also be exhibited by an alkaloid. 



The red colouring substances. 



Luteolin is a flavone derivative, one of a group of yellow dyes produced in 

 the metabolism of plants. It has been identified in Dyer's weed (Reseda 

 luteola], Digitalis purpurea, Genista tinctoria and Erythrophloeum guineiense. 

 It exists in three states: — as free luteolin, as methyl esters, and as glucosides of 

 both of these. It is closely related to the cjuercetin dyes, including Mr. H. G. 

 Smith's myrticolorin, obtained from the leaves of the Eucalyptus. Luteolin is 

 isomeric with fisetin and lotoflavin, also yellow dyes. The latter constitutes one 

 of the groups, with sugar and hydrocyanic acid, forming lotusin, the cyano- 

 genetic glucoside of the lotus plants {Lotus arabicus, L. mistralis, L. corniculatus, 

 etc.). All these flavone derivatives are built round the important pyrone ring, 

 and by the number and position of their hydroxj' groups their tinctorial pro- 

 perties are determined, and the vari<ius members are identified. Luteolin is a 

 tetrahydroxy flavone. 



A most prominent feature throughout this investigation was the deep red 

 colour of the solutions. There is no doubt that this red colouring matter is 

 closely connected with the characteristic colour of the wood, as myrticolorin is 

 with the red stringybark (Eucalyptits macrorhyncha) . 



These flavone glucosides are important metabolic products of the plant tis- 

 sues, and possess an astringent and very bitter taste. The intensely bitter ta.ste 

 of the original extract of the leaves of E. Laboucherii was doubtless in part due 

 to this cause. 



Beferences to Erythrophloeum Laboucherii. 



1. Bentham — Flora Australiensis, ii., 297; Encler, iii., 3, 127- 



2. Mueller, 1859 — Journ. Linn. Soc. Lond., vol. iii., p. 159. 



3. , Australian Acacias and allied genera (with fig.). 



4. , Wittstein's organic constituents of plants (Eng. trans.), p. 331. 



5. Bailey — Flora of Queensland, Part ii. 



6. , Weeds and Poisonous Plants of Q., p. 47 (with fig). 



7. , 1900— The Ironwood Tree. Qland. Agric. Journ., vii., 1900, 153 



(with fig.). 



8. Bennett, F., 1904 — Botany of Irvinebank, Proc. Roy. Soc. Qland., xix., 

 1904, 65. 



9. Planchox, L., 1907 — Recherches sur les E. Ann. Inst. Col. Marseille, ser. 

 2, v., 1907. p. 161-304. through Ju.-<t's Botanischer Jahresbericht, 1908, 36, 

 abth. 1, s. 450. 



10. Meston, a., 1909 — A Remarkable Tree, E. Laboucherii. Sydney Daily 

 Telegraph, Sept. 20th., 1909. 



Beferences to Erythrophloeum guineense. 



11. Procter, 1856 — Erythrophloeum judiciale, the sassy bark tree of Cape 

 Palmas. Pharm. Journ., 16, 1856, 233 (syn. E. guineense). 



