Insecticidal defenses of Piperaceae from the neotropics

Abstract

Insecticidal and growth-reducing properties of extracts of 14 species of American neotropical Piperaceae were investigated by inclusion in diets of a polyphagous lepidopteran, the European corn borer,Ostrinia nubilalis. Nutritional indices suggested most extracts acted by postdigestive toxicity.Piper aduncum, P. tuberculatum, andP. decurrens were among the most active species and were subjected to bioassay-guided isolation of the active components. Dillapiol was isolated from the active fraction ofP. aduncum, piperlonguminine was isolated fromP. tuberculatum, and a novel neolignan fromP. decurrens. The results support other studies on Asian and AfricanPiper species, which suggest that lignans and isobutyl amides are the active defence compounds in this family.

Insect feeding deterrent activity of lignans and related phenylpropanoids with a methylenedioxyphenyl (piperonyl) structure moiety

“…Only safrol (13) was strongly active against all insects with the exception of the T. confusum adults. Safrol was selected as a substitute in our tests for the closely related dilapiol, which is known as an efficient insecticidal defence compound of Piperaceae plants and as a mono-oxygenase activity inhibitor (Bernard et al, 1989(Bernard et al, , 1995. However, Piperaceae plants contain also piperonyl amides, another type of compounds with a methylenedioxyphenyl group, which were described as active insecticides (Su & Horwat, 1981;Bernard et al, 1995).…”

“…Information concerning effects of lignans on insects and their role in plant -insect interactions are still limited (MacRae & Towers, 1984;Harmatha & Nawrot, 1988;Ayres & Loike, 1990;Bernard et al, 1995). The first reports about lignan activity against insects in 1942 concern synergistic action of sesamin and related compounds, asarinin and pinoresinol (all of type D in Figure 1) with pyrethrum insecticides (Haller et al, 1942a,b).…”

“…Some of the lignans were tested for juvenile hormone activity, but they were nearly inactive (Bowers, 1968). Certain structural features, such as the methylenedioxyphenyl (piperonyl) moiety of many lignans became of specific interest and were used as models for selecting natural (Neil, 1989;Bernard et al, 1995) or designing synthetic (Yamauchi & Taniguchi, 1991, 1992a insecticides or insecticide synergists. Also, bioassayguided isolations afforded new lignans with insect growth inhibitory effects (Miyazawa et al, 1994).…”

Toxicidade de óleos essenciais de Piper aduncum e Piper hispidinervum em Sitophilus zeamais

“…Estudos realizados por Bernard et al (1995), com a espécie de P. aduncum, indicaram que essa espécie possui grande quantidade de ligninas, incluindo-se o dilapiol, e que, ao contrário da maioria das espécies desse gênero, não existem amidas relatadas como componentes dessa piperácea. A associação de ligninas ao grupo metilenedioxidofenil é uma característica das piperáceas, que se apresentam em grande número nas plantas e são consideradas importantes inibidores de monooxigenases dependentes do citocromo P450, utilizados, portanto, como sinergistas de inseticidas naturais ( Mukerjee et al, 1979;Bernard et al, 1990).…”

Análise sazonal do potencial antimicrobiano e teores de flavonoides e quinonas de extratos foliares de Aloe arborescens Mill., Xanthorrhoeaceae

“…As amostras de folhas foram fragmentadas e submersas em etanol 99,5 ºGL, agitadas diariamente e o solvente trocado a cada sete dias, perfazendo um total de 28 d de extração. Os filtrados obtidos foram reunidos, constituindo os extratos etanólicos brutos (Bernard et al, 1995), os quais foram lavados com clorofórmio (três vezes), na proporção de 1:1, gerando os extratos clorofórmicos. Os volumes dos extratos foram reduzidos em rotaevaporador a 45 ºC, e as concentrações acertadas a 1%.…”