Carlos Garrido Pinheiro

Seasonal influence on the essential oil production of Nectandra megapotamica (Spreng.) Mez

This study evaluated the seasonal influence on the yield and chemical composition of the essential oil (EO) of Nectandra megapotamica. Fresh young (YL) and old leaves (OL) obtained from three trees in each season (Nov/2010 to Sep/2011) collected in Santa Maria-RS were hydrodistilled in triplicate. The chemical composition was determined by the gas chromatography coupled to mass spectrometry (GC-MS) and the yield on dry basis was evaluated by two-way ANOVA (seasons, development stage). Spring (Sp) and summer (Su) showed higher average incomes (0.45 and 0.33%), which occurred when flowering, fruiting, and growth of YL and senescence of OL took place, while autumn (Au) presented the lowest yield (0.25%) during the rustification of OL. The highest yield was obtained for the YL in Sp (0.59%) and the lowest for the OL in Au (0.21%). The major constituents of the EO were independent from the season and were identified as α-pinene, bicyclogermacrene, β-pinene, germacrene D, and limonene. Seasonality and phenology influenced the production of EO probably due to morphological and metabolic alterations in the leaves as well as due to the needs of the tree, such as attraction and/or protection.

Essential oils of Cunila galioides and Origanum majorana as anesthetics for Rhamdia quelen: efficacy and effects on ventilation and ionoregulation

No presente estudo foi avaliada a eficacia da anestesia e possiveis efeitos dos oleos essenciais (EOs) de Cunila galioides (EOC) e Origanum majorana (EOO) sobre a taxa ventilatoria (VR) e regulacao ionica em Rhamdia quelen. Nas avaliacoes de anestesia, as concentracoes de 50, 100, 200 e 300 μL L-1 EOC e 50, 100, 200, 300, 400 e 500 μL L-1 EOO foram testadas, e os tempos para a inducao as fases de sedacao e de anestesia, assim como recuperacao, foram mensurados. Um segundo ensaio empregou concentracoes mais baixas de ambos EOs: 10, 25, 50 e 100 μL L-1 a fim de verificar a VR e o fluxo liquido corporal dos ions Na+, K+ and Cl- . A sedacao foi alcancada para ambos os oleos em 100 μL L-1, e a anestesia em concentracoes ≥ 200 µL L-1. Nao houve diferenca significativa entre o controle e grupos tratados com EOs em relacao a VR, mas todos os peixes submetidos a 100 µL L-1 do EOC morreram dentro de 2 h de exposicao. No geral, a perda ionica declinou na presenca dos EOs. O EOC em 200 - 300 μL L-1 e o EOO em 400 - 500 μL L-1 apresentam potencial para anestesia rapida em R. quelen.

Larvicidal activity of Brazilian plant essential oils against Coenagrionidae larvae.

ABSTRACT Odonate larvae can be serious pests that attack fish larvae, postlarvae, and fingerlings in fish culture tanks, causing significant loss in the supply and production of juveniles. This study reports a screen of the essential oils (EOs) of Nectandra megapotamica (Sprengel) Mez, Nectandra grandiflora Nees, Hesperozygis ringens (Bentham) Epling, Ocimum gratissimum L., Aloysia gratissima (Gillies & Hooker) Troncoso, and Lippia sidoides Chamisso against Coenagrionidae larvae. In addition, the most effective EO and its 50% lethal concentration (LC50) and chemical analysis are described. The larvae of Acanthagrion Selys, Homeoura Kennedy, Ischnura Charpentier, and Oxyagrion Selys were used to assess the EO effects. EO obtained from H. ringens, O. gratissimum, and L. sidoides showed the highest larvicidal effects at 19 h of treatment.Themajor constituents of theEOofH. ringens include pulegone and limonene, while eugenol and Z-&bgr;-ocimene predominate in the EO of O. gratissimum, and carvacrol and &pgr;-cymene were the major compounds of the EO of L. sidoides. Leaf EOs from H. ringens, O. gratissimum, and L. sidoides showed activity against Coenagrionidae larvae at similar concentrations with LC50s of 62.92, 75.05, and 51.65 µl liter-1, respectively, and these were considered the most promising treatments.

Seasonal variability of the essential oil of Hesperozygis ringens (Benth.) Epling.

This study was developed to evaluate the effect of seasonality on the yield and chemical composition of the essential oil (EO) of Hesperozygis ringens (Benth.) Epling, a native species from the Brazilian Pampa. Leaves were collected from four specimens of a single population in each of the four seasons for a year and were extracted in triplicate by hydro-distillation for 2 hours. The yield of EO (% w/w) was calculated on fresh weight basis (FWB), and the 16 oil samples were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used as statistical tools to evaluate differences in chemical composition. The highest yields were obtained in autumn, spring and summer (2.32-4.38%), while the lowest yields were detected in winter, ranging from 1.15 to 1.91%. Oxygenated monoterpenoids were the predominant class of chemical constituents in the EO obtained in all seasons, showing the highest contents in autumn and summer, and pulegone was identified as a major compound, whose contents varied between 54.13 and 81.17%. The EO samples were divided into three chemical groups by HCA and PCA and were assigned to the same group, except for the three samples gathered in winter. The results showed a seasonal influence on the yield and chemical composition of the EO.

Essential Oil of the Brazilian Native Species Hesperozygis ringens: A Potential Alternative to Control Weeds

Abstract This study evaluated the allelopathic effect of the Hesperozygis ringens essential oil using dicotyledonous and monocotyledonous seeds which are classified as weeds [Bidens pilosa and Lolium multiflorum], bioindicators [Lactuca sativa and Avena strigosa] and crops [Glycine max and Oryza sativa]. The essential oil from the leaves was extracted and analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. The extractive was diluted in ethanol, Tween 20 and water, and then tested at concentrations of 0.25, 0.50, 1.00, 2.50, and 5.00% (v/v). Water and the highest concentration of the solvents were used as control groups. The analyzed variables were germination, emergence velocity index, roots and shoot lengths and total seedlings length. Pulegone was the major essential oil compound representing 82.02% of the composition. Considering dicot seeds, the highest concentration of the extractive completely inhibited the germination of Bidens pilosa without affecting the germination of Lactuca sativa and Glycine max. On monocots, the highest essential oil concentration affected the germination of Lolium multiflorum and Avena strigosa without affecting the Oryza sativa one. The results indicate that the extractive has the potential to control weeds because they were more affected than the crops.

Essential oils from Citrus x aurantium and Citrus x latifolia (Rutaceae) have anesthetic activity and are effective in reducing ion loss in silver catfish ( Rhamdia quelen )

This study investigated the anesthetic effect of the essential oils (EOs) from the peel of Citrus x aurantium (EOCA) and Citrus x latifolia (EOCL) on silver catfish Rhamdia quelen. Fish were exposed to different concentrations of EOCA and EOCL to determine time of anesthesia induction and recovery. Induction of anesthesia was observed in all fish exposed to 400, 600 or 800 µL L−1 EOCA and 300, 400 or 500 µL L−1 EOCL. Another group of fish were exposed for 8 h to 50, 100, or 200 µL L−1 of either EOs. Overall, fish exposed to ethanol and both EOs presented higher ventilatory frequencies (VF) than the control group throughout the 8 h of exposure. Net ion (Na+, K+ and Cl−) effluxes and ammonia excretion were significantly lower in fish exposed to 50, 100 or 200 µL L−1 of either EOs compared to control fish. Mortality was 37% in fish exposed to 200 µL L−1 of either EOs after 8 h. These findings suggest that EOCA and EOCL are useful anesthetics and sedatives for Rhamdia quelen, but their usefulness as alternatives to reduce stress in fish transportation at the lower concentrations tested (50-100 µL L−1) deserves further study.(AU)

Microbiological damage influences the content, chemical composition and the antifungal activity of essential oils in a wild-growing population of Ocotea lancifolia (Schott) Mez

Abstract This study aimed to investigate the variation in essential oils yield, chemical composition and antifungal property in Ocotea lancifolia (Schott) Mez population from Brazil. The oils were obtained by hydrodistillation from the leaves and reproductive organs collected from 12 trees. The volatile composition was established by gas chromatography and the chemical variability was assessed by multivariate procedures. The fungistatic activity against the Fusarium moniliforme was evaluated as well. Higher yields from leaves oils were obtained in spring (1.03%) and summer (0.96%). By multivariate analysis, the oils were separated in two groups. Caryophyllene oxide and bicyclogermacrene were the major constituents in healthy trees (first group) and the oils obtained from damaged trees, which contained β-chenopodiol, constituted the second one. It was observed a significant higher mycelial inhibition for the leaves oils (67.5%). Overall, we identified that the stage of development of the reproductive organs and microbiological damage influenced O. lancifolia oil.

Structural characterization of vegetative organs of the endangered Brazilian native species Hesperozygis ringens (Benth.) Epling

The aim of this study was to describe the structural characterization of Hesperozygis ringens (Benth.) Epling vegetative organs. For this purpose, leaves, stems and roots of the endangered Lamiaceae were collected from a population located in Santo Antão, Santa Maria municipality, Rio Grande do Sul, Brazil. Results demonstrated that the H. ringens leaf blade presents glandular and non-glandular trichomes as well as two morphs of diallelocytic stomata, which are usually found above the epidermis level. The petiole is concave on ventral face and convex on its dorsal face, containing glandular and non-glandular trichomes as well as stomata in the epidermis. These types of trichomes were also detected in the stem. In addition, the presence of intercellular spaces within the organ is highlighted. Stomata above epidermis level also occurred in the stem. Phenolic idioblasts were found in the cortical region of plant root and deposit of lipophilic substance was observed in phloem cells. Great amount of apparently two different crystals were detected in all organs. Information obtained in this study provides knowledge about the characterizationof H. ringens, which may be used to distinguish characters of taxa and can help understand the species survival in its occurrence sites.