THE CHAULMOOGRA TREE AXD RELATED SPECIES. 7 
CHEMISTRY OF CHAULMOOGRA, HYDNOCARPUS, AND GYNO- 
CARDIA OILS. 
By Frederick B. Power, Chemist in Charge of the Phytochemical Laboratory 
of the Bureau of Chemistry. 
The attention which has recently been drawn to the successful 
treatment of leprosy by the use of certain acids contained in chaul- 
moogra oil, or esters prepared therefrom, renders it desirable that 
some account should be given of the original researches which 
led to their discovery and thus made them available as therapeutic 
agents. The investigations to be considered here, unless otherwise 
specified, were conducted several years ago in the Wellcome Chemical 
Research Laboratories, London, and comprised not only an exami- 
nation of the true chaulmoogra oil but also some related products. 
Prior to these investigations nothing of a definite nature was known 
concerning the chemical constituents of these oils, and the statements 
in the literature concerning them were very superficial and inac- 
curate. 
I.— CHAULMOOGRA OIL. 
An authoritative definition of chaulmoogra oil is that given by 
the British Pharmacopoeia, 1914 (9, p. 262), which states it to be 
" the fatty oil expressed from the seeds of Taraktogenos kurzii 
King." The acceptance of this definition is important, especially on 
account of a prevailing tendency to designate the 'oils from some 
closely related botanical sources as chaulmoogra oil. It has been 
shown, however, that the oils from certain species of Hydnocarpus 
are very similar to the true chaulmoogra oil in their physical char- 
acters and chemical composition, and they are known to be used for 
the same purposes in the countries of their production. There would 
therefore seem to be no reason for excluding such oils from medicinal 
use when their botanical source is designated. 
It is not necessary in this place to enter into all the details of the 
respective investigations, especially as a complete account of them 
may be found in easily accessible chemical literature (i, 18, 19, 21). 
It may be stated, however, that in all cases the oils examined by the 
present writer and his collaborators were expressed under the most 
careful supervision from seeds which had been freshly collected and 
botanically identified. There was thus complete assurance of their 
authenticity and purity. 
Chaulmoogra oil is either a brownish yellow liquid or a soft solid 
which melts at about 22° to 30° C. It possesses a characteristic odor 
and somewhat acrid taste. The oil consists to a large extent of the 
glyceryl esters of optically active acids of a type which had not previ- 
ously been found to occur in any fatty oil. These acids are repre- 
sented by the general formula C„H 2 „_ 4 2 and have a cyclic structure. 
