Biological deterrent activity

Peramine (352) is a pyrrole alkaloid identified as a major insect feeding deterrent isolated from perennial ryegrass infected with the entophyte Acre-monium lolii. Due to the interesting heterocyclic ring system and biological activity, the synthesis of peramine is attractive [230],... 

In general, plants do very well in their environments, notwithstanding the omnipresence of a multitude of potential insect herbivores and a number of vertebrate herbivores as well. Some plant species are very insecticidal, as a consequence of their producing a variety of alkaloids including nicotine, piperine, lupine alkaloids, steroidal alkaloids, ephedrine, berberine, strychnine, gramine, and caffeine.37 These biologically active alkaloids also function as deterrents. In terms of families, caffeine is the the most widely distributed alkaloid, a fact that may be... 

The downstream synthesis of two coumarins, ayapin (6,7-methylenedioxy-coumarin) and sco-poletin (6-methoxy-7-hydroxy-coumarin), is of biological interest due to their apparent roles as phytoalexins. Their accumulation has been correlated with resistance to pathogens in Helianthus (Tal and Robeson, 1986a, 1986b) and as feeding deterrents (Olson and Roseland, 1991). Both compounds are found in Jerusalem artichoke tubers (Cabello-Hurtado et al., 1998), and their synthesis via the phenylpropanoid pathway involves the first three steps leading to the activation of 4-coumaroyl CoA (Werck-Reichhart, 1995). Several routes have been postulated ayapin does not appear to be derived from scopoletin (Cabello-Hurtado et al., 1998). 

In spite of the many studies on isolation, activity, and synthesis of natural antifeedants, the number of compounds commercially available remains low, often due to their cost of isolation, availability of the plant source, or low persistence in field conditions. To overcome these drawbacks, much research is conducted on structure—activity relationships (SAR). The rationale behind these studies is to discover the correlation between biological activity and chemical structure and to draw from that optimum structures having both the activity, stability, and selectivity for maximum feeding deterrence.4 5 SAR are much used in drug design6 and have been applied to insecticides.7... 

P h y t o c h e m i c a l investigations of plant species of Parthenium, Encelia and Pi coria (Asteraceae) from semi-arid and arid zones of the United States and Mexico has resulted in the isolation and identification of numerous sesquiterpene lactones and benzopyrans that are active insect feeding deterrents. The chemistry, biological effects and possible mode of action of bioactive pseudoguaianolides and chromenes are reviewed. 

Active ingredient (a.i.) The chemical component of a pesticide formulation or end-use product that is intended to act as a pest deterrent also known as the biologically active chemical agent in a pesticide product (USEPA, 1997c). 

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