Studies on the Stability of Celangulins in Water and theStructures of the Hydrolysates

The stability of the botanical insecticidal components Celangulin V,Celangulin I,NW 28 and NW 53 in three buffer solutions with different pH values at 54℃±1℃ for 24h was studied by high performance liquid chromatography. Celangulin V,Celangulin I and NW 53 were more stable in pH 4 buffer solution,while NW 28 was less stable,the hydrolysis rates of them were 5.03%,4.15%,6.60% and 19.75%,respectively. The stability of four tested compounds in pH 7 buffer solution exhibited similar trend with that of above metioned,and their hydrolysis rates were 6.43%,12.50%,12.03% and 50.55%,respectively. Whereas in pH 10 buffer solution,all tested components were hydrolyzed easily,and their hydrolysis rates were 71.53%,84.55%,77.68% and 99.30%,respectively. The hydrolysates of Celanlulin V were also investigated by means of HPLC-ESI-MS/MS. The results showed that the main hydrolysates were produced from the break of varies ester bonds substituted at C-1,C-2,C-8 and C-9 of the β-dihydroagrofuran sesquiterpene skeleton,in which the structures of five compounds were deduced by their MS/MS spectra.