A Thesis submitted in fulfillment of the requirements for the Degree of Doctor of
Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and
Technology
Baobab (Adansonia digitata L.) is a deciduous non-timber tree species that is facing severe
threats from both anthropogenic and climatic pressures across its range states. Additionally,
baobab seed oil has been used for many years by local populations as medicine to treat
different diseases, beauty, and food purposes. However, consumption of baobab seed oil has
been reported to cause health effects emanating from the presence of carcinogenic ingredients
known as Cyclopropenoid Fatty Acids (CFPAs). Ecological survey and laboratory analysis
were carried out to asses the status of Baobab populations and characterize their fatty acid of
seeds clued oil respectively. In ecological survey, stratified random sampling design
composed of the three land-use types: strictly protected areas, non-strictly protected areas,
and unprotected areas were used to select the grids for the study. Baobabs were sampled in
belt transect of 1 km long and a 50 m wide, which were carried out in 337 grids located in
three different land-uses types. In the laboratory analysis, the physico-chemical properties
were determined according to Official Methods of Analysis of the Association of Official
Analytical Chemists. The quantification of fatty acid before and after heating was done by the
analysis of derivative fatty acid methyl-esters by using Gas-Liquid Chromatography. Baobab
density was found to be highest in strictly protected areas (2.45 ± 1.29) and the lowest in
unprotected areas (1.52 ± 1.00). The density of adult, sub-adult and juvenile populations were
1.53 ± 0.105, 0.82 ± 0.149 and 0.33 ± 0.253 plants/ha respectively. Furthermore, the results
show bell shaped and inverse J-shaped distributions in the unprotected areas and strictly
protected areas, respectively. The number of baobabs damaged was higher than undamaged
in all land-use types. There were no significant differences in terms of physico-chemical
properties in three different regions. It was found that the baobab crude oil contains mainly
twelve essential fatty acids and two different CFPAs. The most abundant fatty acids were
Palmitic acid, Oleic acid and Linoleic acid in all the three regions. The major breakdown of
CPFAs started at 200 °C that would be the best temperature in the refining process of the
baobab oil. The findings from this study are important in understanding the status of baobab
populations and CPFAs of their crude oil in different land uses and serve to inform decision akers towards sustainable management of this species. Furthermore, the information from this
study is vital in understanding the role of biophysical conditions and land uses in shaping the
population persistence of the species in its range areas in Tanzania.