ISSN:
1573-1561
Keywords:
Azadirachtin
;
nimbin
;
salannin
;
antifeedant
;
growth inhibition
;
Azadirachta indica
;
Spodoptera littoralis
;
Locusta migratoria
;
Schistocerca gregaria
;
photooxidation
;
photoisomerization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Nimbin and salannin, major triterpenoids accompanying azadirachtin in extracts of neem (Azadirachta indica) seeds, were photooxidized by UV light in the presence of oxygen to more polar, unstable intermediates that rearranged on silica gel to two final products in which the furan ring had been oxidized to isomeric hydroxybutenolides. The isomeric hydroxybutenolides were also readily formed when a crude extract of triterpenoids from neem seeds was irradiated, and both isomers of salannin have been isolated from seeds. Photooxidation of nimbin and salannin proceeded much faster than that of azadirachtin. All photoproducts showed some biological activity againstSpodoptera littoralis, Locusta migratoria, andSchistocerca gregaria. Isonimbinolide was as potent as azadirachtin at inhibiting feeding in all three species, and it also inhibited the growth ofS. littoralis. Isosalanninolide showed potent antifeedant and growth inhibitory activity againstS. littoralis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022523329255
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