Epilachna borealis

GC analyses of the pupal secretion of E. borealis have indicated the presence of vitamin E acetate and other tocopherol derivatives [49,50]. However, in tests with ants, these compounds proved to be essentially inactive, whereas the secretion itself was potently deterrent. To find and identify the active components in the pupal Epilachna borealis secretion, NMR spectroscopic studies on the fresh secretion were carried out. One and two-dimensional NMR experiments revealed that the tocopheryl acetates account for only a relatively small percentage of the beetles5 total secretion (20%), whereas the major components represented a group of previously undetected compounds. By analysis of the COSY, HSQC and HMBC spectra of the mixture, these components were shown to be esters and amides derived from three (co-l)-(2-hydroxyethylamino)alka-noic acids 44-46. HPLC analyses coupled to a mass spectrometric detector revealed that the secretion contain a highly diverse mixture of macrocyclic polyamines, the polyazamacrolides (PAMLs) 47-52 (Fig. 8). 

Fig. 8 Building blocks and PAMLs found in pupae of Epilachna borealis. In these formulas, each of the variables m to s can have the values 5,6 or 7... 

Fig. 9 Amide isomers isolated from pupae of Epilachna borealis...

FIGURE 11.1 Natural combinatorial libraries from (a) Epilachna borealis (From Schroder, F.C. et al., A combinatorial library of macrocycUc polyamines produced by a ladybird beetle, J. Am. Chem. Soc., 122, 3628, 2000) (b) Landolphia dulcis. (From Staerk, D. et al.. Isolation of a bbrary of aromadendranes from Landolphia dulcis and its characterization using the VolSurf approach, J. Nat. Prod., 67, 799, 2004.)... 

Fig. 7 Alkaloids found in adults of Epilachna varivestis and E. borealis...

---