RESUMEN

Spodoptera frugiperda control methods have proved to be inefficient, which justifies the search for new control measures. In this search for botanical insecticides for controlling S. frugiperda, the following were evaluated: (i) the toxicity of essential oils (EOs) from Cinnamodendron dinisii, Eugenia uniflora, and Melaleuca armillaris; (ii) the effect of EOs on life table parameters against S. frugiperda; (iii) the chemical characterization of EOs; and (iv) the in silico interaction of the chemical constituents present in the three EOs with the molecular targets of S. frugiperda. The EO from E. uniflora had the lowest LD50 (1.19 µg of EO/caterpillar). The major compounds bicyclogermacrene (18.64%) in C. dinisii and terpinolene (57.75%) in M. armillaris are highly predicted to interact with the octopamine receptor (OctpR). The compound 1,8-cineole (21.81%) in M. armillaris interacts mainly with a tolerant methoprene receptor (MET) and curzerene (41.22%) in E. uniflora, which acts on the OctpR receptor. Minor compounds, such as nerolidol in C. dinisii and ß-elemene in E. uniflora, are highly ranked for multiple targets: AChE, MET, OctpR, and 5-HT1. It was concluded that the EO from E. uniflora negatively affects several biological parameters of S. frugiperda development and is promising as an active ingredient in formulations for controlling this insect pest.

RESUMEN

Yarrow (Achillea millefolium L., Asteraceae) is an important medicinal plant used worldwide for its medicinal properties such as the analgesic, antioxidant and anti-inflammatory ones. The aim of this study was to evaluate the growth and production of photosynthetic pigments and of volatile constituents of Achillea millefolium L. under different irrigation depths. The treatments were the application of 55, 110, 220, 440 and 880 mm of water for a period of 110 days. Data were submitted to polynomial regression analysis at 5% probability, while the volatile constituents were analyzed by standard deviation. Different irrigation depths provided quadratic growth responses being the highest dry matter production at the depth of 440 mm. The contents of chlorophyll a, b, total and carotenoids were higher at the lower depth tested (55 mm). The major volatile compounds identified were sabinene, 1,8-cineol, borneol and ß-caryophyllene. Increased water availability reduced the complexity of the volatile fraction of essential oil. Thus, it is recommended that the species be cultivated at 440 mm irrigation depth to have a higher production of dry matter and lower variation in the volatile profile of the essential oil.

Asunto(s)

RESUMEN

The purpose of this investigation was to determine the influence of colored shade nets on the growth, anatomy and essential oil content, yield and chemical composition of Pogostemon cablin. The plants were cultivated under full sunlight, black, blue and red nets. The harvesting was performed 5 months after planting and it was followed by the analysis of plant growth parameters, leaf anatomy, essential oil content, yield and chemical composition. The plants grown under red net have produced more leaf, shoot, total dry weight and leaf area. Plants cultivated under colored nets showed differences in morphological features. Plants maintained under red net had a higher leaf blade thickness and polar and equatorial diameter of the stomata ratio. Additionally, higher yield of essential oil in the leaves was observed under red and blue colored shade net. The essential oil of the plants grown under red net showed the highest relative percentage of patchoulol (66.84%). Therefore, it is possible using colored shade nets to manipulate P. cablin growth, as well as its essential oil production with several chemical compositions. The analyses of principal components allowed observing that pogostol has negative correlation with α-guaiene and α-bulnesene. There was difference in total dry weight and patchoulol content when the patchouli is cultured under the red colored shade nets.

Asunto(s)

RESUMEN

The leaves of Mikania laevigata and Mikania glomerata are used in Brazil to treat respiratory affections, being kaurane-type diterpenes and coumarin considered as the bioactive compounds. The present study reports an investigation on the HPLC-DAD profiles and contents of coumarin (1), trans-o-coumaric (2), kaurenoic (3), benzoylgrandifloric (4) and cinnamoylgrandifloric (5) acids in dried leaves of Mikania species stored in dark room under controlled conditions. Excepting 2, the constituents were isolated and purified to be employed as reference compounds. The samples were analyzed at three monthly intervals up to 18 months for M. laevigata and 12 months for M. glomerata. trans-o-Coumaric was not detected in both, whereas 1 occurred only in M. laevigata. The concentrations of the assayed constituents did not vary significantly within the evaluated period (p < 0.05), for both species. In contrast, changes in the chromatographic profiles and spectral purity of peaks from 3, 4 and 5 were detected in samples of both Mikania stored for three months, while the coumarin profile in M. laevigata modified after six months of storage. The evaluation of chromatographic profiles based on spectral purity analyses of selected peaks was shown to be a more robust tool to access chemical stability of Mikania samples than the quantitation of chemical markers' contents.

Asunto(s)

RESUMEN

Guaco Mikania glomerata Spreng. and M. laevigata Sch. Bip. ex Baker, Asteraceae, has antimicrobial activity and may be helpful in reducing the incidence of oral diseases. This double-blinded randomized clinical trial aimed to evaluate the efficacy of guaco mouthwashes on the disinfection of toothbrushes used by preschool children, tested positive for mutans streptococci (MS), as well as the quantification of its coumarin contents by high performance liquid chromatography. Ethanol extracts were obtained by percolation. The mouthwashes were prepared with 2.5% g/mL M. glomerata and M. laevigata ethanol extracts, standardized for their coumarin content (% mg/mg). Antimicrobial effect of the mouthwashes and extracts were assessed in vitro against Streptococcus mutans (ATCC 25175TM), using 2.4 to 500 µg/mL to calculate the minimum inhibitory concentration (MIC). For the in vivo study, 24 patients were randomly assigned to a 4-stage changeover system with a one-week interval between each stage. All solutions were used in all stages by a different group of children. After brushing without toothpaste, toothbrushes (n=96) were sprayed with water and solutions of M. glomerata (2.5%), M. laevigata (2.5%) and chlorhexidine (0.12%). Microbiological analysis was carried out after 4 h and 30 days, respectively. MIC values were 400, 125 and 14 µg/mL, respectively, for both crude ethanol extracts, mouthwashes of M. glomerata and M. laevigata. Statistical analysis showed that all solutions decreased contamination of toothbrushes by mutans streptococci (chlorhexidine 50.7±17.7%; M. glomerata 37.3±23.7% and M. laevigata 28.7±25.1% of inhibition). Treatment with chlorhexidine and M. glomerata were statistically similar (p>0.05). M. glomerata mouthwash could be useful in herbal strategy programs against mutans streptococci and the marker coumarin may be not related to the activity observed.