Antimicrobial activity of essential oils against Staphylococcus aureus and Staphylococcus chromogenes isolated from bovine mastitis.

Staphylococcus aureus and Staphylococcus chromogenes are pathogens frequently detected in bovine mastitis. Treatment and prevention of this disease have been usually carried on with antimicrobials. However, the emergence of bacterial isolates with antimicrobial resistance has aroused interest in new therapeutic alternatives. Plant essential oils (EOs) have been largely studied as antibacterial treatments. In the present study, EOs from five plants were evaluated for their antibacterial activities against S. aureus and S. chromogenes. Bacterial isolates were obtained in a previous study of clinical cases of bovine mastitis. EOs from lemongrass, eucalyptus, lavender, peppermint, and thyme were obtained by hydrodistillation and their chemical compositions were evaluated by gas chromatography (GC). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated for all EOs. The results demonstrated that citral (40.9%), myrcene (24.7%), and geraniol (1.9%) were detected in lemongrass EO; 1,8-cineole (76.9%), α-pinene (8.2%), and ledene (5.1%) in eucalyptus EO; 1,8-cineole (45.2%), camphor (18.2%), and fenchone (14.6%) in lavender EO; L-menthol (38.5%), menthofuran (16.3%), and citronellal (10.6%) in peppermint EO; and thymol (44.2%), p-cymene (24.6%) and 1,8-cineole (9.9%) in thyme EO. More effective antibacterial activities were observed only with the use of lemongrass (MIC and MBC ranging from 0.39 to 3.12 mg/mL and 0.39 to 6.35 mg/mL, respectively) and thyme (MIC and MBC ranging from 0.39 to 1.56 mg/mL and 0.39 to 3.12 mg/mL, respectively). Peppermint, lavender and eucalyptus EOs did not show bactericidal activities. In conclusion, lemongrass and thyme EOs are promising antibacterial alternatives against Staphylococcus species associated with bovine mastitis.

Insecticidal Activity of Lavandula dentata L. Essential Oil on Anticarsia gemmatalis (Hübner, 1818)

Abstract Anticarsia gemmatalis, commonly known as soybean caterpillar, causes important economic losses in soybean crops. Synthetic pesticides are the standard practice to control this insect. However, the indiscriminate use of these substances has increased the resistance of this pest. Thus, it is necessary to search for different control alternatives that are also more environmentally friendly. The objective of this work was to evaluate the chemical composition of Lavandula dentata L. essential oil (EO) and its activity on A. gemmatalis. The major compounds of essential oil were 1,8-cineole (31.5 wt.%), camphor (16.6 wt.%), and fenchone (15.9 wt.%). Bioassays were performed with third-instar caterpillars. EO concentrations of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0% v/v were diluted in Tween-80® 0.5% v/v and incorporated into the artificial diet given to caterpillars. Water, Tween-80® 0.5% v/v, and novaluron 0.075% w/v were added as negative and positive controls. For the aversion tests, soybean leaf discs were immersed in solutions with 0.4, 0.6, 0.8, and 1.0% v/v of EO, plus a negative control (water), and offered to caterpillars. In the bioassay, 100% mortality was observed from the concentration 0.6% v/v of the essential oil of L. dentata in 24 h; without statistical difference from 0.4 and 0.5% v/v. There was no important change in mortality between 24 and 72 h. In the aversion test, all EO treatments caused deterrence of caterpillars when compared to control, but without difference between EO concentrations. It was observed that L. dentata EO can be used as an alternative in the control of A. gemmatalis.

Bioactivity of Schinus molle L. and Schinus terebinthifolia Raddi. Essential Oils on Anticarsia gemmatalis (Hübner 1818)

Abstract Anticarsia gemmatalis is one of the main pests of the soybean crop, being controlled mainly with agrochemicals. The environmental and health risks, as well as the development of resistance by the pests, has led to the search for alternative control measures, aiming to use more eco-friendly procedures. The objective of this research was to evaluate the chemical composition and the bioactivity of Schinus molle and Schinus terebinthifolia essential oils (EOs) on A. gemmatalis. The major compound in both EOs was α-pinene (60.04 wt.% for S. molle and 38.49 wt.% for S. terebinthifolia). Bioassays were carried out with third instar larvae, with five replicates and each replicate with ten larvae, totaling 50 larvae per treatment. The oils were incorporated in the artificial diet (0.1, 0.5, 1.0, 1.5, and 2.0% v/v). The controls were: water, Tween-80® 0.5% v/v, and novaluron 0.075% v/v. According to the Probit method, the S. terebinthifolia EO presented a LC50 of 1.74% v/v (1.58-1.97% v/v); it was not possible to determine the LC50 for the S. molle EO. The mortality percentage after 24 and 48 h was 52% and 30% at 2.0% v/v for S. terebinthifolia and S. molle oil, respectively. After 72 h, the mortality rate for S. molle EO have not changed; for S. terebinthifolia EO it increased to 70%; the larvae treated with the chemical control (synthetic insecticide) had a mortality of 100%.

Poejo (Cunila galioides Benth. ) Production in Five Agroecological Regions of Rio Grande do Sul

Abstract The objective of this study was to evaluate the biomass and essential oil production of nine populations of poejo (Cunila galioides) cultivated in five agroecological regions of the state of Rio Grande do Sul, under different edaphoclimatic conditions. The experiments were performed in field conditions in Erechim, Caxias do Sul, Pelotas, São Francisco de Paula, and Santa Vitoria do Palmar. The experimental design was completely randomized, with nine populations, eight plants per plot and four repetitions. The following were evaluated: biomass production and essential oil chemical composition and yield. The data underwent ANOVA, followed by Tukey's multiple range test. The adaptability and stability of the populations in the different environments were also evaluated by regression analysis. The results showed great differences between the populations and cultivation sites, with genotype vs. environment interaction. Most populations presented the best biomass production results at Erechim. Pelotas and Santa Vitória do Palmar were the worst locations for poejo production, mainly due to a water deficit occurred during the experiment. The Santa Lucia population presented broad stability and the greatest adaptability to the environments for biomass and essential oil production, but its average production was not satisfactory. The André da Rocha population presented the highest average production of essential oil, and was favored in favorable environments. Regarding essential oil chemical composition, the populations kept stable contents of the major compounds at all locations, with a few variations. In some populations, a higher concentration of sesquiterpenes was observed, which can be attributed to environmental stress.

Fractionation of rosemary (Rosmarinus officinalis L.) essential oil using vacuum fractional distillation.

Rosemary essential oil has many compounds suitable for use in the food, cosmetics and pharmaceuticals industries. This study aimed to evaluate vacuum fractional distillation to separate and purify components of rosemary oil, also to observe the distillation patterns. The light terpenes (α-pinene, myrcene, camphene) were removed at the top of the column, while the oxygen containing components (verbenone, borneol, linalool, geraniol) remained at the bottom. The concentrations of some minor compounds increased more than ten times (borneol, geraniol) compared with the raw oil. There was no evidence of thermal degradation in any of the experiments. Therefore, vacuum fractional distillation may be an interesting process to upgrade rosemary essential oil.

Fodder radish seed cake biochar for soil amendment.

In this work, fodder radish seed cake (FRSC) was pyrolyzed in a rotary kiln reactor at 0, 3, and 6 rpm, at final temperature of 500 °C. Maximum biochar yield was observed at 0 rpm (≈ 26 wt.%). Increase of the rotary speed decreased the volatile matter content and increased the ash content of the biochars. Biochars exhibited alkaline pH (≈ 9.0), low electrical conductivity (< 105.6 dS m-1), and high cation exchange capacity (69 to 78 cmolc kg-1), as well as high nitrogen contents (≈ 80 g kg-1). FTIR analysis presented biochars with similar spectra, with carboxyl and carbonyl groups within the structure, along with aromatic rings and nitrogen containing functions (amides). Biochar incubation experiments in an acrisol at different biochar doses (5 g L-1 soil to 40 g L-1 soil) were performed in order to evaluate changes in soil fertility parameters caused by FRSC biochar application. Results indicated that most of macro (N, P, K, Ca, Mg) and micronutrients (S, Cu, Zn, Mn, B, Na) increased with increase of the dosage, along with the decrease in Al and H+ Al contents. An increase in pH (from 4.25 to 5.33) was also observed, in electric conductivity (from 30.0 to 45.7 dS m-1), and a decrease in soil real density (from 3.67 to 2.99 kg L-1) at the dosage of 40 g char L-1 soil.

Physico-chemical evaluation of Rosmarinus officinalis L. essential oils

Dezenove amostras de Rosmarinus officinalis foram extraídas por destilação por arraste a vapor em uma planta piloto e os óleos essenciais foram avaliados quanto a composição química e características físico-químicas. Os rendimentos de óleo essencial variaram de 0,37% (média de 1999) a 0,49% (média de 1998). Vinte componentes foram identificados nos óleos essenciais. Os componentes majoritários foram a-pineno (40,55 a 45,10%), 1,8-cineol (17,40 a 19,35%), canfeno (4,73 a 6,06%) e verbenona (2,32 a 3,86%). A média por safra dos parâmetros físico-químicos avaliados resultaram em 0,8887g/cm3 para densidade específica, 1,4689 para índice de refração e +11,82º para rotação óptica, sendo que as variações encontradas para os parâmetros químicos e físico-químicos dos óleos essenciais não variaram significativamente em função do ano de produção.