60 Khaled A. Selim, Mohamed M. S. Nagia and Dina E. El. Ghwas
pyrrolizidine alkaloid, namely Penibruguieramine A (17) which possesses an
unusual 1 - alkenyl- 2 - methyl- 8 - hydroxymethylpyrrolizidin- 3 - one skeleton
(Zhou et al., 2014a). Determination of its absolute configuration was
according to its experimental and Time-Dependent Density Functional Theory
(TDDFT) calculated electronic circulardichroism (ECD) spectra. This method
is considered a strong method in assigning the absolute configuration of
natural compounds (Zhou et al., 2014a). Figure (3) summarize the diversity of
alkaloid metabolites isolated from endophytic fungi (structures 1-17).
Figure 3. (Continued).