Lethal and sublethal effects of essential oils fromPiper capitarianumYunck andPiper krukoffiiYunck onPlutella xylostellaL.

Plutella xylostella (L.) is responsible for considerable vegetable crop losses in the metropolitan region of Manaus, Brazil. In recent decades, essential oils have been investigated as an alternative to synthetic insecticides. The genusPiperis widely distributed in Amazonia and essential oils from these plants have insecticidal properties. This study describes the chemical composition of the essential oils fromPiper capiterianumandPiper krukoffiias well as the lethal and sublethal effects onP. xylostella. The phytotoxicity of the oils on the host plant was also evaluated. Globulol was the major constituent of theP. krukoffiioil ando-cymene was the major constituent of theP. capitarianumoil. The oil fromP. capiterianumexhibited greater toxicity to larvae and eggs. This oil also presented greater repellant action, feeding deterrence and mild phytotoxicity to the host plant (Brassicae oleraceae). The findings suggest that this oil can be used in the preparation of a formulated insecticide for the management ofP. xylostellain different development phases. However, further studies are needed to evaluate the effect of this oil on crops under field conditions as well as non-target organisms and determine the cost-benefit ratio of a product formulated withP. capitarianumoil.

Insecticidal properties and chemical composition of Piper aduncum L., Lippia sidoides Cham. and Schinus terebinthifolius Raddi essential oils against Plutella xylostella L.

In the laboratory, were evaluated the effects (residual contact and feeding deterrence) of the essential oils from the leaves of Piper aduncum, Lippia sidoides and Schinus terebinthifolius, as well as eleven selected constituents and binary blends of oils in different proportions against 3rd instar larvae of Plutella xylostella (L.). The Piper oil demonstrated the greatest toxicity (LC50 = 0.31 µL/mL) and feeding deterrence (DC50 = 1.08 µL/mL) between oils tested. Dillapiole (LC50 = 1.01 µL/mL; DC50 = 1.10 µL/mL) and carvacrol (LC50 = 6.03 µL/mL; DC50 = 0.075 µL/mL) demonstrated the greatest toxicity and feeding deterrence between constituents tested, respectively. Based on the fractional effects indices for the blends, a synergistic interaction was found for the blend of the Lippia and Schinus oils at a proportion of 75 and 25%, respectively. The present findings indicate that this blend could be used in the control of P. xylostella, as the literature reports populations resistant to the active ingredient in the positive control, Premio®. Further studies are needed for the development of a new botanical insecticide based on the active ingredients in oils from L. sidoides and S. terebinthifolius to improve efficiency, stability and the cost-benefit in the control of P. xylostella.

Chemical composition and acaricidal activity of essential oils and selected terpenes from two species of Psidium in the Cerrado biome of Brazil against Tetranychus urticae / Composición química y actividad acaricida del aceite esencial y terpenos seleccionados de dos especies de Psidium de Cerrado Biome de Brasil contra Tetranychus urticae

The aim of this study was to investigate the chemical composition and acaricidal effect of two Psidium species essential oils and selected compounds on Tetranychus urticae. Essential oils from the leaves of Psidium laruotteanum and Psidium myrsinites were obtained through hydrodistillation, analyzed using CG-FID and CG-MS and evaluated for toxicity to T. urticae by fumigation and residual contact. The susceptibility of T. urticae to monoterpenes and sesquiterpenes was also investigated. The major constituents of the P. laruotteanum oil were (E)-nerolidol (9.6 ± 0.4%) and γ-terpinene (9.4 ± 0.6%) and the major constituents of the P. myrsinites oil were ß-caryophyllene (21.2 ± 0.9%) and α-humulene (10.3 ± 0.5%). Based on the LC50 estimates, no significant differences were found between the two oils regarding toxicity by fumigation or residual contact. ß-Caryophyllene and (E)-nerolidol had the highest level of toxicity, independently of the method investigated. The findings indicate that both oils and selected constituents, especially ß-caryophyllene and (E)-nerolidol, are promising as natural acaricidal agents that affect T. urticae through more than one mode of action.

Los aceites esenciales de las hojas de Psidium laruotteanum y Psidium myrsinites se obtuvieron por hidrodestilación, se analizaron por CG-FID y CG-MS, y se evaluaron sus toxicidades por fumigación y contacto residual contra Tetranychus urticae. Se investigó también la susceptibilidad del T. urticae a monoterpenos y sesquiterpenos. En el aceite esencial de P. laruotteanum, (E)-nerolidol (9.6 ± 0.4%) y γ-terpinene (9.4 ± 0.6%) se identificaron como constituyentes mayoritarios, mientras que en el aceite esencial de P. myrsinites, ß-caryophyllene (21.2 ± 0.9%) y α-humulene (10.3 ± 0.5%) se encontraron como mayoritarios. Con base en las CL50 estimadas, no se observaron diferencias significativas entre las toxicidades de los aceites por fumigación, y tampoco por contacto residual. ßCaryophyllene y (E)-nerolidol presentaron las mayores toxicidades, independientemente del método investigado. Estos resultados indican, que los dos aceites, así como los constituyentes seleccionados, entre los que se destacan ß-caryophyllene y (E)-nerolidol, son promisores agentes acaricidas naturales por actuar en el T. urticae por más de un mecanismo de acción.

Chemical constituents of apolar fractions from fruit latex of twelve Clusia species (Clusiaceae).

The apolar fractions components of fruit latex of twelve species of Clusia belonging to four different taxonomic sections were examined by GC-MS. The latex of Clusia is characterised by large amounts of sesquiterpene hydrocarbons as major constituents like germacrene D: C. paralicola (44.28 %), C. criuva subsp. criuva (29.03 %); ß-caryophyllene: C. fluminensis (35.61 %), C. lanceolata (36.39 %), C. hilariana (58.10 %); α-trans-bergamontene: C. spirictus-sanctensis (36.30 %); α-bulnesene: C. weddelliana (25.61 %); bicyclogermacrene: C. panapanari (25.93 %) and trans-ß-farnesene: C. nemorosa (24.63 %), while C. grandiflora is composed of 42.16 % monoterpene hydrocarbons. Verbenone (31.91 %) was the major component. In contrast, C. rosea, C. grandiflora, C. lanceolata and C. criuva subsp. parviflora are rich in 3-methylcyclohexanone (19.56 %), hexadecanol (22.72 %), p-anisaldehyde (23.39 %) and octadecanol (26.81 %), respectively. This study suggests considerable chemical variation among the non-polar fractions of fruit latex of the twelve Clusia species.

Comparative toxicity of essential oil and blends of selected terpenes of Ocotea species from Pernambuco, Brazil, against Tetranychus urticae Koch

ABSTRACT Essential oils from the leaves of two species of the genus Ocotea that occur in the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed using gas chromatography-mass spectrometry. The acaricidal activity of these oils as well as 11 selected components and blends were evaluated in fumigation and residual contact tests against the two-spotted spider mite (Tetranychus urticae). Sixty-seven constituents were identified, totaling 97.3 ± 0.3% and 97.8 ± 0.5% of the oils from O. duckei and O. glomerata, respectively. Sesquiterpene was the dominant class. The compounds β-caryophyllene (18.6 ± 0.1%) and aromadendrene (17.3 ± 0.6%) were the main constituents of the oils from O. duckei and O. glomerata, respectively. Acaricidal action varied depending on the method employed, species and chemical nature of the selected constituents. The mites were susceptible to the oils and chemical constituents using the fumigation method. The O. duckei oil was respectively 2.5-fold and 1.5-fold more toxic than the O. glomerata oil using the fumigation and residual contact methods. Among the selected constituents, β-caryophyllene was the most toxic, independently of the method employed. The individual toxicity of the selected compounds and their blends as well as the role of these constituents in the overall toxicity of the essential oils are also discussed.

Comparative toxicity of essential oil and blends of selected terpenes of Ocotea species from Pernambuco, Brazil, against Tetranychus urticae Koch.

Essential oils from the leaves of two species of the genus Ocotea that occur in the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed using gas chromatography-mass spectrometry. The acaricidal activity of these oils as well as 11 selected components and blends were evaluated in fumigation and residual contact tests against the two-spotted spider mite (Tetranychus urticae). Sixty-seven constituents were identified, totaling 97.3 ± 0.3% and 97.8 ± 0.5% of the oils from O. duckei and O. glomerata, respectively. Sesquiterpene was the dominant class. The compounds ß-caryophyllene (18.6 ± 0.1%) and aromadendrene (17.3 ± 0.6%) were the main constituents of the oils from O. duckei and O. glomerata, respectively. Acaricidal action varied depending on the method employed, species and chemical nature of the selected constituents. The mites were susceptible to the oils and chemical constituents using the fumigation method. The O. duckei oil was respectively 2.5-fold and 1.5-fold more toxic than the O. glomerata oil using the fumigation and residual contact methods. Among the selected constituents, ß-caryophyllene was the most toxic, independently of the method employed. The individual toxicity of the selected compounds and their blends as well as the role of these constituents in the overall toxicity of the essential oils are also discussed.

Chemical composition and acaricidal activity of the essential oils from Vitex agnus-castus L. (Verbenaceae) and selected monoterpenes.

Tetranychus urticae is considered one of the main plagues in the world. Its occurrence in Pernambuco was registered for the first time in 1985 and it has caused considerable damage to the farmers, attacking different cultures of agricultural interest. The essential oils from different parts of Vitex agnus-castus harvested in the Atlantic forest in the state of Pernambuco, Brazil, were obtained by hydrodistillation and the acaricidal potential was evaluated against Tetranychus urticae using two methods under laboratory conditions. Gas chromatography-mass spectrometry revealed the presence of 47 components accounting for 98.8 ± 0.0%, 93.0 ± 0.1% and 97.4 ± 1.0% of the essential oils from the leaves, fruit and inflorescence, respectively. The compounds 1,8-cineole and ß-(E)-farnesene were the major components of the oils from the leaves (17.6 ± 0.3% and 13.6 ± 0.2%, respectively) and fruit (17.5 ± 0.1% and 15.4 ± 0.0%, respectively). ß-(E)-farnesene (13.5 ± 0.1%) and ß-caryophyllene (11.7 ± 0.1%) were the major components of the oils from the flowers. Acaricidal action varied depending on the part of the plant and method employed. Through fumigation, the oil from the leaves (CL50= 0.61 µL L-1 of air) was approximately six fold more toxic than the oil from the fruit. However, through residual contact, the oil from the fruit (CL50 = 137.11 µLmL-1) was 1.1 fold more toxic than the oil from the leaves. The relationship between the chemical composition of the oils and acaricidal activity is also presented.

Circadian variation of essential oil from Piper marginatum Jacq / Variaciones circadiana de aceite esencial de Piper marginatum Jacq

The composition of the essential oil from the leaves of Piper marginatum (Piperaceae) shows circadian variation and a higher yield during high solar incidence. The essential oils samples were investigated by GC-FID and GC-MS, which allowed identification of 29 compounds. Principal component analysis (PCA) and cluster analysis (CA) showed a significant quantitative variability in the chemical composition of the studied samples as well as a correlation between the oil profiles and the collection time. Two main groups were observed, with predominance of phenylpropanoids or sesquiterpenes. The predominant chemical compounds were phenylpropanoids, having as main representative (Z)-asarone and (E)-asarone.

La composición del aceite esencial de hojas de Piper marginatum (Piperaceae) muestra una variación circadiana y un mayor rendimiento durante la mayor incidencia solar. Las muestras de aceites esenciales se investigaron por GC-FID y GC-MS, lo que permitió la identificación de 29 compuestos. El análisis de componentes principales y el análisis de conglomerados mostraron una variación cuantitativa significativa en la composición química de las muestras estudiadas, así como una correlación entre los perfiles del aceite esencial y el tiempo de recolección. Se observaron dos grupos principales, con predominio de fenilpropanoides o sesquiterpenos. Los compuestos predominantes fueron los fenilpropanoides, (Z)-asarona y (E)-asarona.

Antibacterial and cytotoxic properties of some plant crude extracts used in Northeastern folk medicine / Propriedades antibacterianas e citotóxicas de alguns extratos de plantas usados na medicina popular nordestina

In the present study, 32 hexane and ethanol extracts of Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans and Muntingia calabura were screened for antibacterial activity by the disc-diffusion method. Cytotoxicity assays using the brine shrimp Artemia salina Leach as a model were performed to determine lethal doses for 50 percent of individuals (LC50 µg/mL). Antibacterial activity was found in flowers hexane extracts of M. calabura against B. subtilis, and leaves ethanol extracts against S. aureus and B. subtilis at concentration of 1mg/mL. Among 32 extracts, 19 showed low or no toxicity (LC50 > 250 µg/mL), 6 showed moderate toxicity (LC50 between 80 µg/mL and 250µg/mL), and 7 were highly toxic (LC50 < 80 µg/mL).

No presente estudo, 32 extratos hexânicos e etanólicos de Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans e Muntingia calabura, foram avaliados para atividade antibacteriana, pelo método de difusão em disco. Ensaios de citoxicidade foram realizados com o modelo do microcrustáceo Artemia salina Leach para determinar a concentração letal para 50 por cento dos indivíduos (CL50 µg/mL). A presença de atividade antibacteriana foi observada com os extratos hexânicos das flores de M. calabura contra B. subtilis, e extratos etanólicos das folhas contra S. aureus and B. subtilis na concentração de 1 mg/mL. Dentre os 32 extratos, 19 apresentaram toxicidade baixa ou ausente (CL50 > 250 µg/mL), 6 mostraram toxicidade moderada (CL50 entre 80 µg/mL e 250 µg/mL) e 7 foram muito tóxicos (CL50 < 80 µg/mL).

Toxicidade de formulações de nim (Azadirachta indica A. Juss.) ao ácaro-rajado e a Euseius alatus De Leon e Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae) / Toxicity of neem (Azadirachta indica A. Juss) formulations for twospotted spider mite and Euseius alatus De Leon and Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae)

A toxicidade de formulações comerciais de nim a Tetranychus urticae Koch (Acari: Tetranychidae) e a dois ácaros predadores, Euseius alatus De Leon e Phytoseiulus macropilis (Banks) foi estudada. A toxicidade tópica foi avaliada com três formulações comerciais (Natuneem, Neemseto e Callneem) e com o extrato de sementes de nim, todos na concentração de 1 por cento, em comparação ao acaricida padrão, abamectina na concentração de 0,3ml/L e ao tratamento controle com água destilada. Com base no melhor efeito tópico sobre T. urticae, a formulação Neemseto foi selecionada para avaliar diferentes concentrações sobre ovos, e o efeito residual e repelente sobre adultos desses ácaros. O tratamento dos ovos consistiu na imersão em diluições de Neemseto por cinco segundos; e o efeito residual e repelente sobre adultos foi avaliado pela imersão de discos de folha nas diluições também por cinco segundos. A toxicidade de Neemseto a ovos e adultos foi maior para T. urticae comparada à toxicidade observada para os ácaros predadores. Neemseto foi repelente para T. urticae e E. alatus, quando testados nas concentrações 0,25; 0,50 e 1,00 por cento, mas não afetou P. macropilis. A fecundidade de T. urticae foi reduzida significativamente por Neemseto em todas as concentrações, enquanto para os ácaros predadores, redução significante na fecundidade foi observada apenas nas maiores concentrações. Assim, nas formulações testadas, Neemseto foi o mais eficiente para o ácaro-rajado e provocou, relativamente, menor impacto aos ácaros predadores estudados.

The toxicity of selected commercial formulations of neem on Tetranychus urticae Koch (Acari: Tetranychidae) and two predatory mites Euseius alatus De Leon and Phytoseiulus macropilis (Banks) was studied. Topical toxicity was tested with the commercial formulations (Natuneem, Neemseto and Callneem) and extract of neem's seeds at concentration 1 percent, compared to the standard acaricide abamectin at concentration of 0.3 ml/L and the control treatment (distilled water). Based on the best performance against T. urticae through topical contact, the formulation Neemseto was selected to be evaluated using different concentrations against eggs, and residual and repellent effects on adults of the mites. Egg treatment consisted of dipping eggs into Neemseto dilutions and control treatment for five seconds. In addition, residual and repellent effects of Neemseto for adult mites consisted of using leaf discs dipped into the dilutions for five seconds. The toxicity of Neemseto on eggs and adults was greater for T. urticae compared to the toxicity observed for the predatory mites. Neemseto was repellent for T. urticae and E. alatus when tested at the concentrations of 0.25, 0.50 and 1.0 percent, and did not affect P. macropilis. Neemseto using all concentrations, while for the predatory mites significant reduction of mite fecundity was only observed at the largest concentrations reduced the fecundity of T. urticae significantly. So Neemseto, among tested neem formulations, performed better against the twospotted spider mite and exhibited relatively low impact against the predatory mites studied.