Gebreyesus, Tarekegn (PhD)Shelwaye, Dejene2018-06-162023-11-092018-06-162023-11-091989-06http://etd.aau.edu.et/handle/12345678/1052Heteronemin, a pentacyclic sesterterpene has been characterized from the chloroform extract of an unidentified sponge sample collected from Massawa, Red Sea. The structure was established by 1H nmr, 13C nmr, and mass spectral interpretation. Another CZ9 compound characterized as S-sitosterol, has been isolated from the chloroform extract of another unidentified sponge sample, collected from the same locality as the first one. The structure of the sterol was characterized by spectral interpretation, and comparing its physical constant~ with authentic sample.enRed SeaThesis