The action of precocenes in milkweed bugs (Oncopeltus fasciatus) and locusts (Locusta migratoria)

Effect of encecalin, euparin and demethylencecalin on thylakoid electron transport and photophosphorylation in isolated spinach chloroplasts

“…Chromenes (benzopyrans) and benzofurans are common metabolites isolated from many species of higher plants ; the majority of these compounds are known to occur in the Asteraceae family (Proksch and Rodriguez 1983). A number of biological properties, including phytogrowth-inhibitory activity, have been described for some of these secondary metabolites (Bowers et al 1976 ;Brooks et al 1979 ;Proksch and Rodr• guez 1983 ;Proksch et al 1985 ;Merrill 1989 ;Castan8 eda et al 1996 ;inter alia). However, their allelopathic role as well as their e †ect on metabolic pathways remains unexplored.…”

Ecocatalysis for 2H-chromenes synthesis: an integrated approach for phytomanagement of polluted ecosystems

“…Precocene I (3a) is a natural insecticide with antijuvenile hormone activity in insects (Brooks et al 1979). EcoZn catalysis allows its synthesis with high yield (91 %) and selectivity (95 %).…”

“…Several articles and patents have been published, concerning the biological activity, mechanism of action, and metabolism of natural 2H-chromenes, specifically precocenes (Adler and Baldwin 2009;Brooks et al 1979;Lv et al 2012;Timar et al 1983). Exposure of young larval stages of test insects to precocenes leads to precocious metamorphosis into unviable adults.…”

“…We focused on juvenile hormone inhibitors in insects such as cockroach (Periplaneta americana Blattidae) (Pratt and Bowers 1977) and milkweed bug (Oncopeltus fasciatus Lygaeidae) (Brooks et al 1979). Such juvenile hormonal inhibitors of natural origins include plant-based 2H-chromenes with insecticidal activities .…”

International Award for Research in Agrochemicals – Experiences of a half-century of insect toxicology (1956-2006)

“…We investigated the necrotic effect on Locusta CA and established that the preapplied benzodioxole analogue of precocene II protected Locusta and Oncopeltus against the anti-JH effects of PII (Brooks et al 1979), proving, with other results, that the effect involves intermediate reactive epoxide and carbonium ion formation, with attack on critical cellular macromolecules in the CA, a fascinating effect which still leaves many unanswered questions.…”