Citrus limonoids and their semisynthetic derivatives as antifeedant agents against Spodoptera frugiperda larvae. A structure-activity relationship study.
The antifeedant activity of Citrus-derived limonoids limonin (1), nomilin (2), and obacunone (3) and their semisynthetic derivatives 4-26 was evaluated against a commercially important pest, Spodoptera frugiperda. Simple chemical conversions were carried out on the natural limonoids obtained from seeds of Citrus limon. These conversions focused on functional groups considered to be important for the biological activity, namely the C-7 carbonyl and the furan ring. In particular, reduction at C-7 afforded the related alcohols, and from these their acetates, oximes, and methoximes were prepared. Hydrogenation of the furan ring was also performed on limonin and obacunone. The known antifeedant properties of the Citrus limonoids are confirmed. Comparison with previously reported data shows that insect species vary in their behavioral responses to these structural modifications. Highly significant antifeedant activity (P < 0.01) for two natural (1 and 3) and three semisynthetic limonoids (4, 8, and 10) was observed against S. frugiperda.
Ruberto
Giuseppe
G
Istituto del C.N.R. di Chimica Biomolecolare-Sezione di Catania,(x) Via del Santuario 110, I-95028 Valverde (CT), Italy. ruberto@issn.ct.cnr.it
Renda
Agatino
A
Tringali
Corrado
C
Napoli
Edoardo M
EM
Simmonds
Monique S J
MS
D000818:Animals; D001584:Benzoxepins / Q000737:chemistry / Q000494:pharmacology; D002957:Citrus / Q000737:chemistry*; D004435:Eating / Q000187:drug effects; D005511:Food Handling; D007220:Industrial Waste; D007306:Insecticides; D007814:Larva / Q000187:drug effects* / Q000502:physiology; D036701:Limonins / Q000737:chemistry / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry; D018411:Spodoptera / Q000187:drug effects*; D013329:Structure-Activity Relationship
D001584:Benzoxepins; D007220:Industrial Waste; D007306:Insecticides; D036701:Limonins; D010936:Plant Extracts; C067207:obacunone; C059405:nomilin; C001546:limonin