Antifeeding effects

Argandona VH, Rovirosa J, San-Martin A, Riquelme A, Diaz-Marrero AR, Cueto M, Darias J, Santana O, Guardano A, Gonzalez-Coloma A (2002) Antifeedant Effects of Marine Halogenated Monoterpenes. J Agric Food Chem 50 7029... 

Antarctic brown macroalgae are also reported to elaborate phlorotannins (polyphenolics)65 66 which, in several temperate and tropical phaeophytes,13 are known to have antifeedant effects. However, the chemical structure and the ecological role of phlorotannins in Antarctic brown macroalgae still remain to be established. 

Powell, K.S., Gatehouse, A.M.R., Hilder, V.A., and Gatehouse, J.A., Antifeedant effects of plant lectins and an enzyme on the adult stage of the rice brown planthopper, Nilaparvata lugens, Entomol. Exp. Appl., 75, 51-59, 1995. 

Moretti, M.D.F., Bazzoni, E., Passino, G.S. and Prota, R. (1998) Antifeedant effects of some essential oils on Ceratitis capitata. Wied. (Diptera, Tephritidae). Journal of Essential Oil Research 1 0, 405-412. 

T. confusum. The iodolactones were found to be weaker antifeedants, unlike the iodolactones of precocenes, which were the only semisynthetic compounds having a strong antifeedant effect. An excellent antifeedant against T. confusum is compound 81, which had an activity that is comparable to that of azadirachtin (213). Its enantiomer 82 was only slightly less active.54... 

The following sections describe a selection of algal metabolites whose antifeedant effects have been investigated in some detail. 

Other soft coral metabolites reported to show antifeedant effects against fish include heterogorgiolide 119 and the eunicellane 120 from Heterogorgia uatumani,iv> and furanocembrenoid diterpenes, for example, 1 3-acetoxy-11 ft, 12/3-epoxypukalide 121, from Lophogorgia violacea.150... 

A mixture of polyandrocarpidine metabolites 15 3—156 from the ascidian Polyandrocarpa sp. deters feeding by hermit crabs and two species of snails.28 Nitrogenous ascidian compounds that are reported to lack antifeedant effects include patellamide C (Lissochnurn patella),28 and eudistomins G and H.176... 

Jensenone Eucalyptusjensenii (gum tree) [antifeedant effect blocked by... 

Thus, the growth Inhibitory activity of abyssinin (I) compared to abyssinols (II-IV) could be attributed to a potent antifeedant effect which can cause starvation. Accordingly, the antifeedant activities of the abyssinols (II-IV) appear not to be strong enough as to force starvation. 

It has been proposed (2) that 24,055 is acting as an antimetaboUte, but work in our laboratory and subsequent work by Lange (3) fail to substantiate this. A nutritional defect would also not appear in a matter of seconds, as does the antifeeding effect. 

Figure 1. Antifeeding effects of para-octopamine versus meta-octopamine (a positional isomer with little activity as an agonist of insect adenylate cyclase), when sprayed on tomato leaves which were then fed to first instar Manduca sexta larvae.

Certain limonoids have been shown to possess antifeedant effects on some insects and anticarcinogenesis activity in mice. Although further research is needed, limonoids appear to have potential as insecticides or chemopreventative agents against cancer. Citrus fruit and seeds are an excellent source of these compounds. 

Destruxins and bassianolide have no importance in practical plant protection because their recovery is cumbersome, they are highly toxic to warm-blooded animals and, moreover, they are not contact poisons. Their activity as a stomach poison is greatly limited by their antifeedant effect. They are primarily products of theoretical interest, and it is to be hoped that study of them will clarify relationships concerning the mechanism of the insecticidal and antifeedant effects, and will help elucidate the biological effect of cyclodepsipeptide antibiotics of similar structure. 

Ascher et al. (1967) found that triphenyl tin hydroxide (fentin hydroxide, 34) and triphenyltin acetate (fentin acetate, 35), already known for their fungicidal and insect antifeedant effect, also show insect sterilising activity. They assumed that the sterilisation of male insects is brought about by a slow poisoning of the sperm. 

During an infestation by larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd) in the summer of 1978, it was noticed that shrubs of Physalis peruviana L. (cape gooseberry) were not attacked, whereas other Physalis and Nicandra spp. suffered heavy damage. Asher and co-workers demonstrated that withanolide E (118) and 4(3-hydroxywithanolide E (119), isolated from P. peruviana, as well as several related steroids, had insect antifeedant properties. Further studies on other withanolides showed antifeedant effects and species-specific activity on three insects, S. littoralis (Boisd.) (Lepidoptera), the Mexican bean beetle, Epilachna varivestis Muls. (Coleoptera) and the red flour beetle, Tribolium castaneum (Herbst) [62]. 

The structure-activity study of the ryanoids showed that both C-l and C-14 substituents play an important role in their antifeedant and toxic activity against S. littoralis, as previously shown for their antifeedant effects on S. litura [10]. The p-stereochemistry at C-l (5 versus 3) and its O- acetylation (4), increased the toxic and/or antifeedant activity of these compounds. Hydroxylation (1), 0- acetylation (2) and pyrrolcarboxylate-esterification (10) at C-l 4 along with the hydrophobicity of the cyclohexane ring (6) resulted in intermediate activities. Additionally, the presence of a C-2/C-3 epoxide (15,16) increased the toxicity against this lepidopteran (table 2, Figure (1)) [17]. 

Table 2. Average antifeedant effect (%FI) + standard error, and effective antifeedant doses (EC50) of the test compounds against S. littoralis sixth-instar (L6) larvae and L. decemlineata adults in choice assays [17].

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