Avaliação fitoquímica de Campylopus surinamensis Müll. Hal. E Calymperes lonchophyllum Schwägr. (Bryophyta) no controle da lagarto-do-cartucho do milho Spodoptera frugiperda J. E. Smith (Lepidoptera).

Abstract

The bryoflora is abundant worldwide and is present in virtually all Earth's ecosystems. An important focus on bryophyte studies is the knowledge of the chemical composition of extracts and essential oils or concentrate volatiles. These plants are important sources of natural terpenes, esters, acetogenins, aromatic compounds, alkaloids, phenolic compounds (flavonoids), tannins, saponins, fatty acids, cardiac glycosides, and others. Many of these chemical constituents possess aromas and an intense bitter or pungent flavor, which highlights the use of bryophytes in insect control, guaranteeing them a great importance as insecticide or antifeedant plants. The lack of literature on the phytochemical investigation of bryophytes species is a big gap in the research for this plant group. Therefore, this study aimed to analyze the volatile chemical constituents of the mosses species Campylopus surinamensis (Dicranaceae) and Calymperes lonchophyllum (Calymperaceae) occurring in the Brazilian Amazon and evaluate the effect of its ethanol extract in the control of the fall armyworm Spodoptera frugiperda in 3rd instar, in controlled conditions. The samples were collected in a fragment of the Amazon forest in Parque Ecológico de Gunma, municipality of Santa Bárbara, Pará State, on terrestrial and corticicolous substrates. The pentanic extracts obtained by simultaneous distillation-extraction (SDE) were analyzed by gas chromatography / mass spectrometry (GC-MS). The ethanol extracts obtained by cold maceration with PА ethanol were diluted in dimethylsulfoxide (DMSO), to achieve the mortality and antifeedant tests in the caterpillar of S. frugiperda in the 3rd instar. Five treatments were applied (2.0, 1.0, 0.5 and 0.25 µg/µL and control with DMSO diluted in water). The experimental data were submitted to analysis of variance, for antifeedant activity, with its means compared using the Mann-Whitney U test and for mortality was applied the Fischer's test with Tocher's modification. 34 chemical constituents were identified, belonging to the group of aromatic hydrocarbons, aldehydes, terpenes, phenylpropanoids, esters and fatty acids. Naphthalene was the predominant aromatic hydrocarbon in C. lonchophyllum and C. surinamensis (71.8 and 45.71%, respectively). This is the first report of the volatile chemical composition of these species, and the results suggest that these mosses are important sources of natural terpenes, fatty acids and esters. As for antifeedant activity and mortality, for Campylopus surinamensis was observed antifeedant action of extracts at concentrations of 2.00 µg/µL, 1.00 µg/µL and 0.50 µg/µL after 24 hours of contact and no insecticidal effect. For Calymperes lonchophyllum only after 48 hours of contact of the caterpillars with treatments 1, 2 and 3, was observed an antifeedant activity. To produce insecticidal effect on caterpillars of 3rd instar were required 72 hours of extract exposure at concentrations of 2.00 and 1.00 ug/uL. These species of mosses can be of great importance and interest for the control of S. frugiperda in corn fields. There are not other studies in the specialized literature assessing the insecticide and/or antifeedant effect of these mosses, which is the first scientific research to test this biological activity. These results are subject to patent, thus protecting the right of authorship.