Doryopteris triphylla (Pteridaceae-Cheilanthoideae) grows in xeric habitats in Brazil, Paraguay, Uruguay and Argentina. The aim of this study was to characterize D. triphylla anatomically, histochemically and cytogene...Doryopteris triphylla (Pteridaceae-Cheilanthoideae) grows in xeric habitats in Brazil, Paraguay, Uruguay and Argentina. The aim of this study was to characterize D. triphylla anatomically, histochemically and cytogenetically. For anatomical characterization, rhizomes, roots, petioles and leaves were made and then stained using Safranine-Astra Blue for further observations. Leaf blades were also cleared. For histochemical analysis, leaf cross sections were stained with different reagents to identify glandular trichomes compounds. For cytogenetic characterization, a karyogram was performed using laboratory cultivated roots. Results show a dictyostelic rhizome covered with scales with apical secreting gland;diarch roots;petiole cross-sections show thick cuticle, uniseriate epidermis, parenchymatic cortex cells with thick walls and a vascular bundle with two xylem groups;and hypostomatic fronds with glandular trichomes. Histochemical studies of secretion products of the glandular trichomes were positive for polysaccharides, pectins, lipids, acid lipids, dihydroxyphenols, phenols and flavonoids. Cytogenetically, D. triphylla is described as a diploid species (2n = 60), with chromosomes gradually decreasing in size. The apical glands in scales of rhizomes, the presence of two xylem groups in the vascular bundle in the petiole and the glandular trichomes on the abaxial surface are new contributions to the species. The type of chemical products secreted by glandular leaf trichomes and karyotype estimation is shown for the first time in this species.展开更多
Annonaceous acetogenins (ACG), belonging to the family Annonaceae, represent a class of bioactive compounds whose toxic effects have been reported for several spe-cies of insects. Given their insecticidal properties, ...Annonaceous acetogenins (ACG), belonging to the family Annonaceae, represent a class of bioactive compounds whose toxic effects have been reported for several spe-cies of insects. Given their insecticidal properties, we first carried out the isolation of the ACG from a Brazilian collection of the seeds of Annona squamosa (Annonaceae) and prepared their methoxy methylated (MOM) and acetylated (OAc) derivatives by chemical methods. ACG analogues were semi-synthesized and characterized by spec-troscopic techniques (<sup>1</sup>H and <sup>13</sup>C-NMR). We isolated ten natural acetogenins: squamo-cin, molvizarin, motrilin, rolliniastatin-2, almunequin, cherimolin-1, cherimolin-2, an-nonacin, squamocin D and asiminecin. The main objective of this study is to report the antifeedant, toxic and nutritional effects of three of those natural acetogenins and their acetylated and methoxy methylated derivatives on Spodoptera frugiperda Smith (Lep-idoptera: Noctuidae). The natural ACGs squamocin and molvizarin killed 100% of S. frugiperda larvae, followed by motrilin (80%). Acetylated derivatives had less toxic and nutritional effects that led to pupal mortality and adult fatal malformations. The addition of MOM derivatives to the larval diet has not toxic effects on larvae, but significantly reduces growth rate and efficiency in conversion of ingested food into biomass, affecting adult survival.展开更多
A treatment based on the acetogenin fraction of the methanol extract of Rollinia occidentalis seeds was applied to soybean crops for three consecutive years. In relation to the control population, the treatment reduce...A treatment based on the acetogenin fraction of the methanol extract of Rollinia occidentalis seeds was applied to soybean crops for three consecutive years. In relation to the control population, the treatment reduced the population of Anticarsia gemmatalis, Rachiplusia nu, Pseudoplusia includens, Loxostege bifidalis and Spodoptera frugiperda to 52% and 65% after 48 h of application at concentrations of 500 and 750 μg/mL respectively, while low toxic effects were detected on natural enemies. The extract treatment at 500 μg/mL and a solution of the annonaceous acetogenin, squamocin, at 50 and 100 μg/mL, were also applied to a corn field to produce 75%, 93% and 100% mortality rates on the population of S. frugiperda, respectively, after 72 h of application. In addition, damages caused by lepidopterans in treated crops were lower than those observed in non treated fields, evaluated by residual biomass. This statement is based on data from trials with the commercially available insecticides lufenuron and cypermethrin.展开更多
Background: Annonaceous acetogenins enclose a large number of biological activities, among which the insecticidal stands out. Methods: We report herein the biocide effects of natural acetogenins from Annona squamosa, ...Background: Annonaceous acetogenins enclose a large number of biological activities, among which the insecticidal stands out. Methods: We report herein the biocide effects of natural acetogenins from Annona squamosa, A.?muricata and A. montana seeds: annonacin, cis-annonacin, cis-annonacin-10- one, asimicin, rolliniastatin-2, cherimolin-1, cherimolin-2, almuñequin, and two β-OH acetogenins: laherradurin and itrabin on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae). Also, some acetylated and methoxy methylated ACG derivatives were synthesized and evaluated: annonacin (3 OAc), annonacin (4 OAc), asimicin (3 OAc), rolliniastatin-2 (3 OAc), rolliniastatin-2 (MOM), laherradurin (3 OAc) and itrabin (3 OAc). Results: The natural acetogenin rolliniastatin-2 (100 μg·g-1 of diet) produced the most important toxic action causing 100% mortality of early instar larvae. Derivatization of ACG yielded compounds that produced nutritional alterations. The incorporation of rolliniastatin-2 (3 OAc) and rolliniastatin-2 (3 MOM) (100 μg·g-1) into the artificial diet of Spodoptera frugiperdadisplayed the strongest antifeedant effects causing marked decreasings in larval growth and adult lethal malformations. Conclusion: Natural acetogenins are promising metabolites for insect control. Derivatization of these compounds reduces their toxicity to early instar larvae.展开更多
Toxic and nutritional effects of annonaceous acetogenins and their semisynthetic analogues on Spodoptera frugiperda were evaluated. Structural modification of the natural ACG, blocking the OH flanking THF with MOM, al...Toxic and nutritional effects of annonaceous acetogenins and their semisynthetic analogues on Spodoptera frugiperda were evaluated. Structural modification of the natural ACG, blocking the OH flanking THF with MOM, allowed us to suggest the mode of action of ACG in the membrane. Our study emphasizes the role of the flanking OH and acetyl groups of THF with the membrane hydrophilic polar head groups. They are essential structural factors in the ACG that facilitate the intermolecular interaction that dehydrates the membrane and makes it potentially toxic against Spodoptera frugiperda.展开更多
文摘Doryopteris triphylla (Pteridaceae-Cheilanthoideae) grows in xeric habitats in Brazil, Paraguay, Uruguay and Argentina. The aim of this study was to characterize D. triphylla anatomically, histochemically and cytogenetically. For anatomical characterization, rhizomes, roots, petioles and leaves were made and then stained using Safranine-Astra Blue for further observations. Leaf blades were also cleared. For histochemical analysis, leaf cross sections were stained with different reagents to identify glandular trichomes compounds. For cytogenetic characterization, a karyogram was performed using laboratory cultivated roots. Results show a dictyostelic rhizome covered with scales with apical secreting gland;diarch roots;petiole cross-sections show thick cuticle, uniseriate epidermis, parenchymatic cortex cells with thick walls and a vascular bundle with two xylem groups;and hypostomatic fronds with glandular trichomes. Histochemical studies of secretion products of the glandular trichomes were positive for polysaccharides, pectins, lipids, acid lipids, dihydroxyphenols, phenols and flavonoids. Cytogenetically, D. triphylla is described as a diploid species (2n = 60), with chromosomes gradually decreasing in size. The apical glands in scales of rhizomes, the presence of two xylem groups in the vascular bundle in the petiole and the glandular trichomes on the abaxial surface are new contributions to the species. The type of chemical products secreted by glandular leaf trichomes and karyotype estimation is shown for the first time in this species.
文摘Annonaceous acetogenins (ACG), belonging to the family Annonaceae, represent a class of bioactive compounds whose toxic effects have been reported for several spe-cies of insects. Given their insecticidal properties, we first carried out the isolation of the ACG from a Brazilian collection of the seeds of Annona squamosa (Annonaceae) and prepared their methoxy methylated (MOM) and acetylated (OAc) derivatives by chemical methods. ACG analogues were semi-synthesized and characterized by spec-troscopic techniques (<sup>1</sup>H and <sup>13</sup>C-NMR). We isolated ten natural acetogenins: squamo-cin, molvizarin, motrilin, rolliniastatin-2, almunequin, cherimolin-1, cherimolin-2, an-nonacin, squamocin D and asiminecin. The main objective of this study is to report the antifeedant, toxic and nutritional effects of three of those natural acetogenins and their acetylated and methoxy methylated derivatives on Spodoptera frugiperda Smith (Lep-idoptera: Noctuidae). The natural ACGs squamocin and molvizarin killed 100% of S. frugiperda larvae, followed by motrilin (80%). Acetylated derivatives had less toxic and nutritional effects that led to pupal mortality and adult fatal malformations. The addition of MOM derivatives to the larval diet has not toxic effects on larvae, but significantly reduces growth rate and efficiency in conversion of ingested food into biomass, affecting adult survival.
文摘A treatment based on the acetogenin fraction of the methanol extract of Rollinia occidentalis seeds was applied to soybean crops for three consecutive years. In relation to the control population, the treatment reduced the population of Anticarsia gemmatalis, Rachiplusia nu, Pseudoplusia includens, Loxostege bifidalis and Spodoptera frugiperda to 52% and 65% after 48 h of application at concentrations of 500 and 750 μg/mL respectively, while low toxic effects were detected on natural enemies. The extract treatment at 500 μg/mL and a solution of the annonaceous acetogenin, squamocin, at 50 and 100 μg/mL, were also applied to a corn field to produce 75%, 93% and 100% mortality rates on the population of S. frugiperda, respectively, after 72 h of application. In addition, damages caused by lepidopterans in treated crops were lower than those observed in non treated fields, evaluated by residual biomass. This statement is based on data from trials with the commercially available insecticides lufenuron and cypermethrin.
文摘Background: Annonaceous acetogenins enclose a large number of biological activities, among which the insecticidal stands out. Methods: We report herein the biocide effects of natural acetogenins from Annona squamosa, A.?muricata and A. montana seeds: annonacin, cis-annonacin, cis-annonacin-10- one, asimicin, rolliniastatin-2, cherimolin-1, cherimolin-2, almuñequin, and two β-OH acetogenins: laherradurin and itrabin on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae). Also, some acetylated and methoxy methylated ACG derivatives were synthesized and evaluated: annonacin (3 OAc), annonacin (4 OAc), asimicin (3 OAc), rolliniastatin-2 (3 OAc), rolliniastatin-2 (MOM), laherradurin (3 OAc) and itrabin (3 OAc). Results: The natural acetogenin rolliniastatin-2 (100 μg·g-1 of diet) produced the most important toxic action causing 100% mortality of early instar larvae. Derivatization of ACG yielded compounds that produced nutritional alterations. The incorporation of rolliniastatin-2 (3 OAc) and rolliniastatin-2 (3 MOM) (100 μg·g-1) into the artificial diet of Spodoptera frugiperdadisplayed the strongest antifeedant effects causing marked decreasings in larval growth and adult lethal malformations. Conclusion: Natural acetogenins are promising metabolites for insect control. Derivatization of these compounds reduces their toxicity to early instar larvae.
文摘Toxic and nutritional effects of annonaceous acetogenins and their semisynthetic analogues on Spodoptera frugiperda were evaluated. Structural modification of the natural ACG, blocking the OH flanking THF with MOM, allowed us to suggest the mode of action of ACG in the membrane. Our study emphasizes the role of the flanking OH and acetyl groups of THF with the membrane hydrophilic polar head groups. They are essential structural factors in the ACG that facilitate the intermolecular interaction that dehydrates the membrane and makes it potentially toxic against Spodoptera frugiperda.
