Saponins as Insecticides: a Review

Chaieb, I. 2010. Saponins as insecticides: a review. Tunisian Journal of Plant Protection 5: 3950. Saponins are heterosides (substances containing in their structure one or more sugar molecule) of plant origin. This type of molecules has an interesting pesticide potential and this review constitutes an inventory of principal researches realized in this direction. In the first part of this review, saponins are defined and their different structural families are presented. The biological significance and principal sources of saponins were also outlined. The second part of this review focused on insecticidal activities of saponins. In fact, these substances are known by their toxicity to harmful insects (anti-feeding, disturbance of the moult, growth regulation, mortality...); the insecticidal activity of saponins is due to their interaction with cholesterol, causing a disturbance of the synthesis of ecdysteroids. These substances are also protease inhibitors or cytotoxic to certain insects. The third part of the review gave an idea on the limits which can slow down the use of saponins as insecticides: saponins have a strong toxicity to mammals because of their cytotoxic and haemolytic activities. The second constraint is the loss of molecule activity due to degradation of sugars associated with the aglycone. The hydrophilic nature of saponins limits their penetration through the lipophilic insect cuticle. The structural complexity of saponins limits the exact identification and synthesis of active molecules.