190 The Philippine Journal of Science iw? 



HYMENODICTYON EXCELSUM WALL (?) 88 (RUBIACE.E) 



Tubo-bato (Tagbanua in Palawan), abar (II. in Abra and 

 Uocos Sur), alegango (T. in Bulacan), mag-talisay (V. in Gui- 

 maras Island), balangcari (T. in Nueva Ecija), malatabaco 

 hibao (T. in Rizal), and huliganga (T. in Batangas). 



This rubiaceous plant, which once acquired some renown in 

 India, Blanco erroneously classified as Exostemma philippicum. 



In view of the opinion of some writers who claim the possibil- 

 ity of using its bark as a substitute for quinine as a febrifuge, 

 a chemical trial was made to obtain the hymenodictyonine, the 

 alkaloid obtained by Naylor :9 from the Indian Hymenodictyon 

 excelsum. We were unable to isolate the alkaloid described 

 by Naylor. 



The fact that the alkaloid that apparently characterizes the 

 Indian Hymenodictyon excelsum Wall, was not found in the bark 

 of Philippine Hymenodictyon raises some doubt as to whether or 

 not the plant found in the Philippines belongs to that species. 

 Our identification of the Philippine material as H. excelsum 

 follows the determination of Philippine material made at Kew, 

 England. 



Following we quote what Dymock writes in his vegetable 

 materia medica of Western India : 40 



In 1870, Broughton examined the fresh bark of one of the Hymenodic- 

 tyons, and found that the bitter taste was due to the existence of aesculin, 

 and that the bark when dry was almost tasteless owing to the transforma- 

 tion of that substance into aesculetin the decomposition having been in- 

 duced by contact with decaying organic matter. 



The fact here mentioned that the bark when dry lost its bit- 

 terness leads us to suppose that it was not that of H. excelsum 

 but of H. obovatum, the dry bark of the former tree being ex- 

 tremely bitter. 



CHEMICAL EXAMINATION OF HYMENODICTYON EXCELSUM 



Both the fresh and dried bark were used in these analy- 

 ses. The fresh bark treated with water and heated to 90° C. 

 gives a highly satisfactory extraction of the active principle. 

 The fluorescent filtrate was clarified with neutral lead acetate 



3S The Philippine plant is a Hymenodictyon very closely allied to, if not 

 identical with, H. excelsum Wall. A critical comparison with type material 

 will be necessary definitely to determine whether one or two species are 

 involved. 



33 Naylor, W. A. H., Pharm. Journ. (1883-4), 14, 311. 



40 Dymock, W., The Vegetable Materia Medica of Western India. 2d. ed. 

 (1885), 404. 



