Content and distribution of the secondary phenolic compound homonataloin in Aloe hereroensis leaves according to leaf part, position and monthly changes

Aloe hereroensis is a succulent shrub distributed in the deserts and arid zones of South Africa, Namibia and Angola. Juice extracted from freshly harvested leaves was freeze-dried. Homonataloin levels were determined spectrophotometically at λ(max)342-344 nm after thin layer chromatography separation using silica gel 60. Terminal younger leaves contained significantly higher concentrations of the secondary phenolic compound homonataloin than all the lower and older leaves. The top third of each leaf contained the highest concentration of homonataloin and the base third the lowest. The importance of homonataloin peripheral distribution in the plant is discussed.