ships. The medicinal properties are due to the presence 
of irritant and purgative resins (6, 83). Ipomoea Purga 
Hayne is the best known of the score or more medicinal 
members of the genus. 
‘That members of the genus /pomoea were well known 
medicinals in Central America before the arrival of the 
Spanish is demonstrated by the inclusion of species of 
Ipomoea in many ancient Mayan prescriptions (21). A- 
mong those used, the following were important: Ipomoea 
pentaphylla Jaeqg., a medicinal for earaches (gum) and for 
eczema (leaves): J. stnuwata Ort., found to be used as a 
general panacea; J. carnea Jacq. which provided, in its 
leaves and roots, an antidote for certain poisons; the 
juice of the leaves of J. Meyert G.Don which was used 
for earaches, while the fruit, prepared with other plant in- 
gredients, was employed as a laxative. An unidentified 
plant, ar-can-ak (**snake vine’’), with tuberous roots and 
climbing habit (probably 2 member of the Convoloula- 
ceae) found use as a remedy for sores on the eyes (21). 
ee 
Hernandez (8) reported this use for ololiuqui among the 
Aztecs.” 
The chemistry of the Convoloulaceae is impertectly 
known. The exact constitution of the resins of the group 
is unknown, but the active principles are all glucosides, 
with the exception of the gluco-alkaloid recently reported 
in Rivea corymbosa (26). The resins of the Convolvulaceae 
ure classed as glucoretin (83). A number of glucosides 
have been reported in the family, but it is now believed 
that there is only one: convoloulin (jalapin, jalapurgin, 
scammonin); turpethin is now thought to be impure con- 
volvulin, and pharbitisin and tpomein to be mixtures of 
constituents (88). It is evident that the Convolvulaceae 
present a promising field for further research in botany, 
ethnobotany, chemistry, and pharmacology. 
[76 | 
