On the Occurrence of Two Kinds of Mannan in the 

 Root of Conophallus konyaku. 



BY 



Y. Kinoshita, Nogakushi. 



The root of Conophallus konyaku has been recently in- 

 vestigated by Mr. C. Tsuji, who found that it contains a large 

 amount of an anhydride of mannose, but it was not shown by him 

 whether only one or several polyanhydrides are present. It 

 has been proved, however, that there exist both soluble and 

 insoluble mannans; to the former belongs, for instance, the 

 mannan discovered in yeast, to the latter that found in the nuts 

 of Pliytclcphas. The fact that an aqueous decoction of the 

 konyaku-root is so slimy that it serves in this country for 

 technical purposes, as for pasting clothes, etc., made it very 

 probable that some of the mannan is present in the soluble 

 form. 



Special experiments have convinced me that, by treatment 

 of the konyaku-root with diluted sulphuric acid, neither glucose 

 nor galactose, xylose nor arabinose is formed. The sugar 

 appears to be mannose and nothing else. I could neither 

 obtain mucic acid by its oxidation with nitric acid nor the red 

 pentose reaction with phloroglucin and hydrochloric acid, nor did 

 the filtrate from the mannose-phenyl-hydrazone (prepared in 

 concentrated solution) yield any notable amount of an osazone. 



I extracted a portion of the finely ground root repeatedly 

 with boiling water, until the extract had no longer any slimy 

 character. The residue yielded mannose, upon boiling with 

 dilute sulphuric acid, as was ascertained, beyond doubt, by its 

 phenyl-hydrazone. The slimy extract of the root was mixed 

 with alcohol, which formed a copious, almost white, Hocculent 

 precipitate, that was filtered off and washed with dilute 

 alcohol. Its solution in water was so opalescent that no test 



(i) This Bull. Vol. II. No. 2. 



