Marco Andre Alves de Souza

Produção de biomassa e óleo essencial de hortelã em hidroponia em função de nitrogênio e fósforo

An experiment was carried out, using a hydroponic system to study the effect of plant nutrition regimes on the plant growth and the production of essential oils in Mentha piperita (mint). Plants were grown in nutrient solutions with varying levels of N and P: 120 and 16; 60 and 16; 120 and 4; 60 and 4, mg L-1 of N and P in the treatments 1; 2; 3 and 4 respectively. Plants of the treatment 4 (29 days after starting the treatments, DAT) presented the highest production of essential oils. However, plants presented the highest biomass production at 64 DAT. The higher the N levels in the nutrient solution, the lower the production of essential oils. Higher N inputs resulted in higher total biomass. There was a negative relationship between the plant cycle and the production of essential oils. Mint plants grown in hydroponics systems can be harvested at 29 DAT for the production of essentials oils, saving time and costs of production.

Atividade biológica do lapachol e de alguns derivados sobre o desenvolvimento fúngico e em germinação de sementes

The natural quinones lapachol, α-lapachone and β-lapachone, and the synthetic derivative β-lapachone-3-sulfonic-acid were assayed for inhibition of fungal growth (Fusarium oxysporum) and germination of lettuce seeds (Lactuca sativa L.). β-Lapachone has the strongest activity as a germination inhibitor and lapachol shows no effect. β-Lapachone, followed by lapachol, are the most active in reducing fungal growth.

In vitro efficacy of essential oils and extracts of Schinus molle L. against Ctenocephalides felis felis.

Extracts and essential oils from plants are important natural sources of pesticides. These compounds are considered an alternative to control ectoparasites of veterinary importance. Schinus molle, an endemic species of Brazil, produces a high level of essential oil and several other compounds. The aim of this work was to determinate the chemical composition of extracts and essential oils of S. molle and further to evaluate the activity against eggs and adults of Ctenocephalides felis felis, a predominant flea that infests dogs and cats in Brazil. In an in vitro assay, the non-polar (n-hexane) extract showed 100% efficacy (800 µg cm(-2); LD50 = 524·80 µg cm(-2)) at 24 and 48 h. Its major compound was lupenone (50·25%). Essential oils from fruits and leaves were evaluated, and had 100% efficacy against adult fleas at 800 µg cm(-2) (LD50 = 353·95 µg cm(-2)) and at 50 µg cm(-2) (LD50 = 12·02 µg cm(-2)), respectively. On the other hand, the essential oil from fruits and leaves was not active against flea eggs. This is the first study that reports the insecticidal effects of essential oils and extracts obtained from Schinus molle against Ctenocephalides felis felis.

Influence of light intensity on glandular trichome density, gene expression and essential oil of menthol mint (Mentha arvensis L.)

Abstract The effects of 25, 50, 75 and 100% of light intensity (137, 254, 406 and 543 μmol photons m−2 second−1, respectively) on aspects related to volatile synthesis in menthol mint were investigated. Fresh weight production, glandular trichome density and essential oil content showed a significant linear positive correlation with light intensity. Plants under low light intensity (25%) produced an essential oil with high levels of neomenthol, menthol and menthyl acetate. With 50 and 75% of light intensity plants showed an increase in expression of limonene synthase, limonene hydroxylase, (-)-isopiperitenol dehydrogenase, (+)-pulegone reductase and menthol dehydrogenase genes and an anticipation in oil maturity. With 25% of light intensity plants produced an essential oil with the best commercial profile. However, plants under 100% of light intensity produced more essential oil but with lower levels of menthol and higher levels of pulegone, that can be toxic for humans.

Synthesis, characterization, and biological activity of a new class of dialkylphosphorylhydrazone derivatives of isatin

Sixteen dialkylphosphorylhydrazones were synthesized by condensation of phosphorylhydrazines with substituted isatins. Products were characterized by FTIR, 1H-NMR, 13C-NMR, and 31P-NMR. Fungicidal activities of these compounds against Rhizoctonia solani and Fusarium oxysporum were also evaluated. Some compounds inhibited the growth of Rhizoctonia solani and Fusarium oxysporum by 43% and 51%, respectively. These compounds exhibited no effects on germination of lettuce seeds (Lactuca sativa L).

Germinação de sementes de alface e de duas ervas invasoras com a aplicação de um novo análogo do estrigol, sintetizado a partir do safrol

O estrigol e um sesquiterpeno natural que possui elevada atividade como estimulante da germinacao, principalmente de sementes de especies invasoras, pertencentes aos generos Striga e Orobanche. Solucoes contendo 0,01; 0,1; 10 e 1000 mg/L de um novo analogo de estrigol, sintetizado a partir de um alilbenzeno natural, o safrol (isolado do oleo de sassafraz), foram aplicadas em sementes de alface e de Ipomoea grandifolia e Bidens pilosa. Observou-se que houve efeito estimulador na germinacao das sementes das ervas invasoras, sem afetar a germinacao da alface. Os resultados indicam que essa substância apresenta potencial de uso para estimular a germinacao de sementes de ervas invasoras, que poderiam ser eliminadas do solo, antes do plantio de hortalicas como a alface.

Essential Oils Composition and Toxicity Tested by Fumigation Against Callosobruchus maculatus (Coleoptera: Bruchidae) Pest of Stored Cowpea

Insect infestation on stored cowpea (Vigna unguiculata) is an economic obstacle to agriculture. In this context, a test in laboratorial scale was proposed aiming to investigate Ocimum gratissimum, O. basilicum, Cymbopogon nardus, C. citratus, Lippia alba, Mentha arvensis, Schinus terebinthifolius and Cordia verbenacea essential oils (EOs) fumigant potential on control of cowpea-weevil (Callosobruchus maculatus) life cycle. Thus, EOs were extracted and analyzed by GC/MS, furthermore, were used for evaluating mortality, oviposition and new adults emergence. As a result of EOs analyses linalool (32.8%) and eugenol (48.1%) in O. basilicum; eucalyptol (14.8%) and eugenol (74.5%) in O. gratissimum; menthyl acetate (10%) and menthol (73.3%) in M. arvensis; citronellal (50.3%) and nerol (10.8%) in C. nardus; citral (75.8 and 87.1%) in C. citratus and L. alba respectively; α-santalene (35.8%) and β-sinensal (17.7%) in C. verbenacea and α-pinene (23,1%), -3-carene (32.1%) and limonene (16.9%) in S. terebinthifolius were reported. In biological tests, EOs showed toxic effect on cowpea-weevil life cycle, inhibiting over 80 and 98% oviposition and new insects emergence, respectively, except for C. verbenacea EO.