THE BARBALOIN CONTENT AND DISTRIBUTION IN ALOE ARBORESCENS LEAVES ACCORDING TO THE LEAF PART, AGE, POSITION, AND SEASON

Abstract

The distribution of the secondary phenolic compound, barbaloin, in Aloe arborescens leaves depends on the leaf part, age, and position of the leaf, as well as on seasonal influences. Young and old leaves of A. arborescens were cut from plants monthly and the exudate was immediately freeze-dried. The barbaloin levels were determined spectrophotometrically at λmax, 360–362 nm after separation by TLC. In all leaves the tissue of the basal third of the leaf had the lowest barbaloin content, the upper third contained the highest percentage, and the middle part contained the intermediate percentage. After cutting young leaves, the new basal part that grows after replanting has a higher barbaloin content after about five months when compared with the same part before cutting. In the 16 leaves of a cutting rooted two years before the experiment, the highest barbaloin content was found in the four upper young leaves (63%). In all the other leaves the barbaloin content was found to be only between 13 and 22%. There are also seasonal influences on the barbaloin content of young leaves. When old and young leaves were compared, the higher barbaloin content was found in the young leaves harvested at the same time.