Eucalyptus Globulus

The aim of the present study was to investigate the chemical composition of essential oils extracted from leaves of Eucalyptus globulus (E. globulus) plant, using gas-chromatography coupled with mass spectrometry (GC/MS) method, and to evaluate their antioxidant capacity by means of 1, 1-diphenyl-2-picrylhydrazyl (DPPH), reducing power, and β-carotene/linoleic acid assays, as well as their antibacterial activity against the major Gram-negative periodontopathogenic (Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis) and Gram-positive cariogenic (Streptococcus mutans, Streptococcus sobrinus) bacterial species. The GC/MS analysis allowed the identification of 26 compounds with the predominance of oxygenated monoterpenes (78.58%); 1,8-Cineole (55.29%), Spathulenol (7.44%) and α- Terpineol (5.46%) being the main components. The tested oil exhibited a weak antioxidant capacity, but a marked antibacterial activity against Gram negative bacteria, more specifically F. nucleatum ATCC 25586 (MIC= 1.14 mg/mL) and P. gingivalis ATCC33277 (MIC= 0.28 mg/mL). Therefore, essential oils from E. globulus may have a potential therapeutic application for the treatment of periodontal diseases.

Soils provide the largest terrestrial carbon store, the largest atmospheric CO2 source, the largest terrestrial N2O source and the largest terrestrial CH4 sink, as mediated through root and soil microbial processes. A change in land use or management can alter these soil processes such that net greenhouse gas exchange may increase or decrease. We measured soil–atmosphere exchange of CO2, N2O and CH4 in four adjacent land-use systems (native eucalypt woodland, clover-grass pasture, Pinus radiata and Eucalyptus globulus plantation) for short, but continuous, periods between October 2005 and June 2006 using an automated trace gas measurement system near Albany in southwest Western Australia. Mean N2O emission in the pasture was 26.6 μg N m−2 h−1, significantly greater than in the natural and managed forests (< 2.0 μg N m−2 h−1). N2O emission from pasture soil increased after rainfall events (up to 100 μg N m−2 h−1) and as soil water content increased into winter, whereas no soil water response was detected in the forest systems. Gross nitrification through 15N isotope dilution in all land-use systems was small at water holding capacity < 30%, and under optimum soil water conditions gross nitrification ranged between < 0.1 and 1.0 mg N kg−1 h−1, being least in the native woodland/eucalypt plantation < pine plantation < pasture. Forest soils were a constant CH4 sink, up to −20 μg C m−2 h−1 in the native woodland. Pasture soil was an occasional CH4 source, but weak CH4 sink overall (−3 μg C m−2 h−1). There were no strong correlations (R < 0.4) between CH4 flux and soil moisture or temperature. Soil CO2 emissions (35–55 mg C m−2 h−1) correlated with soil water content (R < 0.5) in all but the E. globulus plantation. Soil N2O emissions from improved pastures can be considerable and comparable with intensively managed, irrigated and fertilised dairy pastures. In all land uses, soil N2O emissions exceeded soil CH4 uptake on a carbon dioxide equivalent basis. Overall, afforestation of improved pastures (i) decreases soil N2O emissions and (ii) increases soil CH4 uptake.

This work evaluates the effect of SuperBatch™(SB), CompactCooking™(CC) and Lo-Solids™ (LS) modified cooking methods on the cell wall surface of Eucalyptus globulus and Eucalyptus nitens. The kappa target was 17±0.5. The pulps were bleached with sequence D0E1D1E2D2. E. globulus pulps presented higher screen yield and brightness than E. nitens which needed higher H-factor to reach kappa number target. Independently of the cooking method or species all the samples consumed similar amount of ClO2 to reach brightness of 90% ISO. E.nitens pulps showed lower carbohydrates and higher extractives content on fiber surface, regardless of the cooking method. E.nitens presented slightly higher surface charge of the bleached pulps. Surface charges of CC and LS pulps are higher independently of cooked Eucalyptus species. Water retention value (WRV) for E. nitens pulps were higher than for E. globulus. No differences were observed in refinability of different cooking methods, however E.nitens pulps showed higher tensile and lower bulk compared to E.globulus. No correlation between surface composition, fiber surface properties, and paper technical properties among the cooking methods could be determined.

Aromatic plants and their essential oils have been used since antiquity in flavor and fragrances, as condiments or spices, in medicines, as antimicrobial/insecticidal agents, and to protect stored products. The present study was undertaken: to determine (:) the chemical composition of essential oils extract from Eucalyptus globulus (E. globulus) fruits, using Gas-Chromatography coupled with Mass Spectrometry (GC/MS) method, to examine their antioxidant activity (DPPH’, reducing power and lipid peroxidation inhibition assays) compared to that of Butylated hydroxyanisole (BHA) standard, and to estimate their antibacterial effects against reference pathogenic strains: Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Listeria innocua (L. innocua), Escherichia coli (E. coli), Pseudomonas aerugenosa (P. aerugenosa), compared to that of two antibiotics (tetracycline and gentamicin). Twenty eight volatile compounds were identified, with the predominance of sesquiterpenes and oxygenated sesquiterpenes compounds (61.2%). The results of the antioxidant activities (DPPH scavenging activity, reducing power and inhibition of lipid peroxidation activity) of essential oils extract revealed weak activities with IC50 values of 27.0 ± 0.2 mg mL−1, 32.9 ± 1.8 mg mL−1 and 4.9 ± 0.2 mg mL−1, respectively; as compared to those of Butylated hydroxyanisole (BHA) standard that were about 0.05 ± 0.0 mg mL−1, 0.03 ± 0.0 mg mL−1 and 0.5± 0.2 mg mL−1, respectively. The antibacterial activity shows an inhibition effect of essential oils extracts against all the tested bacteria with MIC of 3 and 4 mg mL−1. A bactericidal effect is observed, with MBC varying between 3.6 and 9.0 mg mL−1, which demonstrates the sensibility of all tested bacteria to the essential oils of E. globulus fruits.

This work evaluates the effect of SuperBatch™ (SB), CompactCooking™ (CC), and Lo-Solids™ (LS) modified cooking concepts on pulp bleachability of Eucalyptus globulus and Eucalyptus nitens. E. globulus wood samples presented higher amounts of cellulose and E. nitens higher amounts of hemicellulose and acetone extractives. The same trend was observed in brownstock and in fully-bleached pulps. E. globulus wood sample presented lower amounts of lignin and higher S/G ratio than E. nitens. In the brownstock pulps the amount of Hexenuronic Acids (HexA) and total lignin for E. globulus and E. nitens did not present significant difference variation in the contribution to kappa number 17±0.5. No significant differences were found in intrinsic viscosity among modified cooking methods in unbleached and in fully-bleached pulps. For both species, the CC produced pulps with the highest hemicelluloses content after cooking to the fully-bleached pulp. In this work one cannot observe differences in bleachability of E. globulus and E. nitens caused by different modified cooking concepts.

Heartwood and sapwood from a 18-yr-old Eucalyptus globulus tree were characterized by Py-GC/MS(FID) in respect to carbohydrates and lignin content, and by the carbohydrates-to-lignin ratio (C/L). Heartwood and sapwood presented similar contents of carbohydrates (74 %) and lignin (23 %) in an extractive-free basis. The C/L ratio was also similar, around 3.0. The wood samples were kraft pulped at isothermal conditions (130, 150 and 170 ºC), through several cooking times (1 to 185 min). During delignification, either lignin but also carbohydrates were removed, which was reflected in C/L values. The ratio maintained constant (between 5 and 10) when 60% of lignin and 20 to 25 % of carbohydrates were removed. The ratio increased when the carbohydrates loss maintained constant (around 30 %), but lignin removal continued.