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Green manure (GM) may reduce the use of chemical fertilizers, been an ecologically appropriate strategy to cultivation of medicinal plants. Crotalaria juncea, is one of the most used because it adapts to different climatic and high nitrogen content. Origanum vulgare. is widely used in cooking, pharmaceutical, cosmetic industries and food products. The objectives of this study were to evaluate the GM on biomass, essential oil (EO), phenolic and antioxidant. The experiment consisted: control; 150, 300, 450, and 600 g (Sh= leaves+steam) more 200 g roots (R); 600 g aerial part; 200 g roots; and soil with 300 g cattle manure per pot. The highest dry weights were observed in the presence of GM and cattle manure (90 days). The control had an EO production 75% lower in relation to the dose of 450 g GM (Sh+R). Principal component analysis showed that GM and cattle manure positively influenced the dry weight, content, yield, and EO constituents, and total flavonoids. The GM contributed to the accumulation of the major EO compounds (trans-sabinene hydrate, thymol, terpinen-4-ol). The GM management may be beneficial for cultivating, because it can increase the production of biomass and the active components, in addition to being an inexpensive resource.

The objective of this study was to evaluate the effect of ChromatiNet on vegetative growth, total antioxidant capacity, phenolic and essential oils (EOs) composition of Lippia gracilis. The plants were cultivated under full sunlight, black, blue and red ChromatiNet. The flavonoid content and antioxidant capacity were quantified spectrophotometrically. The C-glycosylflavone isomers (orientin and isoorientin) were isolated and identified by conventional spectroscopic techniques and measured using high-performance liquid chromatography-diode array detection. The EO was analysed by gas chromatography and gas chromatography-mass spectrometry. Environment influenced growth, total antioxidant capacity and phytochemical levels. Shoot dry weight, thymol, carvacrol and (E)-caryophyllene were favoured under red and black ChromatiNet. Root growth, EOs, caryophyllene oxide, p-cymene, flavonoids, orientin and isoorientin were favoured in sunlight. Growth and accumulation of EOs, flavonoids and photosynthetic pigments increased under blue ChromatiNet. Therefore, Lippia gracilis plants have plasticity related to the spectral quality of light and it cultivate depends of the phytochemicals of interest., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

Populations of Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) have shown resistance to insecticides of the carbamate and organophosphate classes. The objective of this study was to assess the susceptibility of C. quinquefasciatus larvae to essential oils from leaves of Eugenia uniflora L., Melaleuca armillaris (Sol. ex Gaertn.) Sm., and Schinus molle L and C. quinquefasciatus larvae's biochemical responses after their exposure to these leaves. The essential oils were chemically analyzed by GC and GC/MS. First, the lethal concentration for 50% (LC 50 ) values was estimated using different concentrations of essential oils and probit analysis. The larvae were exposed for 1 h at the LC 50 estimated for each essential oil. The susceptibility of the larvae to essential oils was evaluated using the following biochemical parameters: concentrations of total protein and reduced glutathione; levels of production of hydrogen peroxide and lipid peroxidation; and the activity of the enzyme acetylcholinesterase (AChE). The main chemical constituents in E. uniflora were E-β-ocimene, curzerene, germacrene B, and germacrone; in M. armillaris were 1,8-cineole and terpinolene; and in S. molle were sabinene, myrcene, and sylvestrene. The essential oils had LC 50 values between 31.52 and 60.08 mg/L, all of which were considered effective. All of them also promoted changes in biochemical parameters when compared to the control treatment. The essential oils of S. molle and E. uniflora inhibited the activity of the AChE enzyme, and the essential oil of M. armillaris increased it. All essential oils had larvicidal activity against C. quinquefasciatus, but the essential oil of E. uniflora was the most efficient. Thus, the findings of the present study suggest that the essential oil of E. uniflora can be considered promising for the development of botanical larvicides., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Synthetic insecticides applied to control Spodoptera frugiperda (Lepidoptera: Noctuidae) can have negative impacts on environment and human health. Botanical essential oils can be sources of organic molecules with biocontrol potential and advantages, such as minor impacts on the selection of resistant pest insects and low toxicity to humans. The aim of this study was to investigate the biocontrol action of essential oils from Brazilian species and methyl chavicol compounds on the development and metabolism of S. frugiperda. Essential oils of Eremanthus erythropappus (Asteraceae), Ocimum selloi, Hyptis suaveolens, and Hyptis marrubioides (Lamiaceae) were distilled by the steam distillation method and analyzed by gas chromatograph techniques. The essential oils were incorporated into an artificial diet (at 1, 2, and 4 mg mL -1 ) and offered to S. frugiperda caterpillars. Larvae of S. frugiperda at 48 h of age were fed an artificial diet containing the major constituent of O. selloi (methyl chavicol). The major compounds of the essential oils were methyl chavicol for O. selloi, α-bisabolol for E. erythropappus, bicyclogermacrene for H. suaveolens, and β-thujone for H. marrubioides. O. selloi caused 100% mortality in S. frugiperda larvae at a concentration of 1 mg mL -1 after 48 h. H. marrubioides essential oil caused 100% mortality in larvae at a concentration of 4 mg mL -1 after 48 h. O. selloi and H. marrubioides inhibited acetylcholinesterase (AchE) activity in 72.87% and 81.69% of larvae, respectively. O. selloi presented the highest toxicity to S. frugiperda and the lowest inhibition of AchE. Methyl chavicol was lethal to all larvae within 24 h at a concentration of 0.92 mg mL -1 of diet. Methyl chavicol showed the best insecticidal activity and potential to be used as a natural insecticide to control S. frugiperda.

Lippia rotundifolia Cham. is in the family Verbenaceae and is endemic to the Cerrado. This species is aromatic and characterized by the presence of glandular trichomes on its leaves that are rich in monoterpenes. The objective of this study was to evaluate the growth, photosynthetic pigment production, and chemical composition of L. rotundifolia grown in vitro under different light wavelengths and intensities. The light intensities consisted of five treatments using cool white fluorescent lamps at 20, 54, 78, 88, and 110 μmol m -2  s -1 . The light quality consisted of six treatments using light-emitting diodes (LEDs) in different light wavelengths, namely, white, red, blue, and their interactions: 1R:1B, 2.5R:1B, and 1R:2.5B. After 45 days, the biometric parameters, photosynthetic pigment content, and volatile compounds were evaluated. The lower light intensities of 20 and 54 μmol m -2  s -1 generated higher growth, photosynthetic pigment content, and biomass accumulation. Myrcene and pentadecane were highest under light intensities of 88 and 110 μmol m -2  s -1 , respectively. The highest limonene and ocimenone levels were obtained at 20 and 54 μmol m -2  s -1 intensity, respectively, and the highest myrcenone content was obtained at 78 μmol m -2  s -1 intensity. Regarding the light wavelengths, the combination of red and blue spectra further stimulated plantlet growth, and the 2.5R:1B combination obtained the best biometric data and total chlorophyll content. The z-ocimenone chemical compound contents were highest under the 1R:2.5B light spectrum. The monochromatic blue spectrum increased the myrcene and limonene content but decreased the myrcenone content, which was increased by red light. The highest pentadecane contents were obtained with the white spectrum and the red and blue combinations., (Copyright © 2019 Elsevier B.V. All rights reserved.)

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 β-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.

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.

Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN) and blue (BN) both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade). The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.